,,the ,,moon ,a ,,full ,,description ,,and ,,map ,,of ,,its ,,principal ,,physical ,,features ,,by ,,thomas ,,gwyn ,,elger1 ,f4,r4,a4,s4 ,,director ,,of ,,the ,,lunar ,,section ,,of ,,the ,,british ,,astronomical ,,association ,,ex-,,president ,,liverpool ,,astronomical ,,society ,altri fiumi1 altri laghi1 altre campagne ,sono la su che non son qui tra noi1 ,altri piani1 altre valli1 altre montagne4 ,,orlando ,,furioso1 ,canto xxxii4 ,,london ,,george ,,philip ,,son1 #cb ,,fleet ,,street1 ,e4,c4 ,,liverpool3 #de ,,to #ea ,,south ,,castle ,,street #ahie ,,preface ,this book and the accompanying map is chiefly intended for the use of lunar observers1 but it is hoped it may be acceptable to many who1 though they cannot strictly be thus described1 take a general interest in astronomy4 ,the increasing number of those who possess astronomical telescopes1 and devote more or less of their leisure in following some particular line of research1 is shown by the great success in recent years of societies1 such as the ,british ,astronomical ,association with its several branches1 the ,astronomical ,society of the ,pacific1 and similar institutions in various parts of the world4 ,these societies are not only doing much in popularising the sublimest of the sciences1 but are the means of developing and organising the capabilities of their members by discouraging aimless and desultory observations1 and by pointing out how individual effort may be utilised and made of permanent value in almost every department of astronomy4 ,the work of the astronomer1 like that of the votary of almost every other science1 is becoming every year more and more specialised2 and among its manifold subdivisions1 the study of the physical features of the moon is undoubtedly increasing in popularity and importance4 ,to those who are pursuing such observations1 it is believed that this book will be a useful companion to the telescope1 and convenient for reference4 ,great care has been taken in the preparation of the map1 which1 so far as the positions of the various objects represented are concerned1 is based on the last edition of ,beer and ,madler's chart1 and on the more recent and much larger and elaborate map of ,schmidt2 while as regards the shape and details of most of the formations1 the author's drawings and a large number of photographs have been utilised4 ,even on so small a scale as eighteen inches to the moon's diameter1 more detail might have been inserted1 but this1 at the expense of distinctness1 would have detracted from the value of the map for handy reference in the usually dim light of the observatory1 without adding to its utility in other ways4 ,every named formation is prominently shown2 and most other features of interest1 including the principal rill-systems1 are represented1 though1 as regards these1 no attempt is made to indicate all their manifold details and ramifications1 which1 to do effectually1 would in very many instances require a map on a much larger scale than any that has yet appeared4 ,the insertion of meridian lines and parallels of latitude at every ten degrees1 and the substitution of names for reference numbers1 will add to the usefulness of the map4 ,with respect to the text1 a large proportion of the objects in the ,catalogue and in the ,appendix have been observed and drawn by the author many times during the last thirty years1 and described in ,the ,observatory and other publications4 ,he has had1 besides1 the advantage of consulting excellent sketches by ,mr ,w4,h4 ,,maw1 ,f4,r4,a4,s41 ,dr4 ,,sheldon1 ,f4,r4,a4,s41 ,mr4 ,a4 ,,mee1 ,f4,r4,a4,s41 ,mr4 ,g4,p4 ,,hallowes1 ,f4,r4,a4,s41 ,dr4 ,,smart1 ,f4,r4,a4,s41 ,mr4 ,t4 ,,gordon1 ,f4,r4,a4,s41 ,mr4 ,g4,t4 ,,davis1 ,herr ,,brenner1 ,herr ,,krieger1 ,mr4 ,h4 ,,corder1 and other members of the ,british ,astronomical ,association4 ,through the courtesy of ,professor ,,holden1 ,director of the ,lick ,observatory1 and ,m4 ,,prinz1 of the ,royal ,observatory of ,brussels1 many beautiful photographs and direct photographic enlargements have been available1 as have also the exquisite heliogravures received by the author from ,dr4 ,l4 ,,weinek1 ,director of the ,imperial ,observatory of ,prague1 and the admirable examples of the photographic work of ,,mm4 ,,paul and ,,prosper ,,henry of the ,paris ,observatory1 which are occasionally published in ,knowledge4 ,the numerous representations of lunar objects which have appeared from time to time in that storehouse of astronomical information1 ,the ,english ,mechanic1 and the invaluable notes in ,celestial ,objects for ,common ,telescopes1 and in various periodicals1 by the late ,,rev4 ,,prebendary ,,webb1 to whom ,selenography and ,astronomy generally owe so much1 have also been consulted4 ,as a rule1 all the more prominent and important features are described1 though very frequently interesting details are referred to which1 from their minuteness1 could not be shown in the map4 ,the measurements 7given in round numbers7 are derived in most instances from ,,neison',s 7,nevill7 ,moon1 though occasionally those in the introduction to ,schmidt's chart are adopted4 ,,thomas ,,gywn ,,elger4 ,,bedford1 #ahie4 ,,contents ,,introduction ,,maria1 ,,or ,,plains1 ,,termed ,,seas ,,ridges ,,ring-,,mountains1 ,,craters1 ,c4 ,walled ,plains ,mountain ,rings ,ring-,plains ,craters ,crater ,cones ,craterlets1 ,crater ,pits ,,mountain ,,ranges1 ,,isolated ,,mountains1 c4 ,,clefts1 ,,or ,,rills ,,faults ,,valleys ,,bright ,,ray-,,systems ,,the ,,moon',s ,,albedo1 ,,surface ,,brightness1 c4 ,,temperature ,,of ,,the ,,moon',s ,,surface ,,lunar ,,observation ,,progress ,,of ,,selenography1 ,,lunar ,,photography ,,catalogue ,,of ,,lunar ,,formations ,,first ,,quadrant-- ,west ,longitude #ij deg4 to #fj deg4 ,west ,longitude #fj deg4 to #dj deg4 ,west ,longitude #dj deg4 to #bj deg4 ,west ,longitude #bj deg4 to #j deg4 ,,second ,,quadrant-- ,east ,longitude #j deg4 to #bj deg4 ,east ,longitude #bj deg4 to #dj deg4 ,east ,longitude #dj deg4 to #fj deg4 ,east ,longitude #fj deg4 to #ij deg4 ,,third ,,quadrant-- ,east ,longitude #j deg4 to #bj deg4 ,east ,longitude #bj deg4 to #dj deg4 ,east ,longitude #dj deg4 to #fj deg4 ,east ,longitude #fj deg4 to #ij deg4 ,,fourth ,,quadrant-- ,west ,longitude #ij deg4 to #fj deg4 ,west ,longitude #fj deg4 to #dj deg4 ,west ,longitude #dj deg4 to #bj deg4 ,west ,longitude #bj deg4 to #j deg4 ,,map ,,of ,,the ,,moon ,first ,quadrant ,second ,quadrant ,third ,quadrant ,fourth ,quadrant ,,appendix ,description of ,map ,list of the ,maria1 or ,grey ,plains1 termed ,seas1 c4 ,list of some of the most ,prominent ,mountain ,ranges1 ,promontories1 ,isolated ,mountains1 and ,remarkable ,hills ,list of the ,principal ,ray-,systems1 ,light-,surrounded ,craters1 and ,light ,spots ,position of the ,lunar ,terminator ,lunar ,elements ,alphabetical ,list of ,formations ,,introduction ,we know1 both by tradition and published records1 that from the earliest times the faint grey and light spots which diversify the face of our satellite excited the wonder and stimulated the curiosity of mankind1 giving rise to suppositions more or less crude and erroneous as to their actual nature and significance4 ,it is true that ,anaxagoras1 five centuries before our era1 and probably other philosophers preceding him1 --certainly ,plutarch at a much later date--taught that these delicate markings and differences of tint1 obvious to every one with normal vision1 point to the existence of hills and valleys on her surface2 the latter maintaining that the irregularities of outline presented by the terminator1 or line of demarcation between the illumined and unillumined portion of her spherical superficies1 are due to mountains and their shadows2 but more than fifteen centuries elapsed before the truth of this sagacious conjecture was unquestionably demonstrated4 ,selenography1 as a branch of observational astronomy1 dates from the spring of #afji1 when ,galileo directed his optic tube to the moon1 and in the following year1 in the ,sidereus ,nuncius1 or the ,intelligencer of the ,stars1 gave to an astonished and incredulous world an account of the unsuspected marvels it revealed4 ,in this remarkable little book we have the first attempt to represent the telescopic aspect of the moon's visible surface in the five rude woodcuts representing the curious features he perceived thereon1 whose form and arrangement1 he tells us1 reminded him of the ocelli on the feathers of a peacock's tail1--a quaint but not altogether inappropriate simile to describe the appearance of groups of the larger ring-mountains partially illuminated by the sun1 when seen in a small telescope4 ,the bright and dusky areas1 so obvious to the unaided sight1 were found by ,galileo to be due to a very manifest difference in the character of the lunar surface1 a large portion of the northern hemisphere1 and no inconsiderable part of the south-eastern quadrant1 being seen to consist of large grey monotonous tracts1 often bordered by lofty mountains1 while the remainder of the superficies was much more conspicuously brilliant1 and1 moreover1 included by far the greater number of those curious ring- mountains and other extraordinary features whose remarkable aspect and peculiar arrangement first attracted his attention4 ,struck by the analogy which these contrasted regions present to the land and water surfaces of our globe1 he suspected that the former are represented on the moon by the brighter and more rugged1 and the latter by the smoother and more level areas2 a view1 however1 which ,kepler more distinctly formulated in the dictum1 ,do maculas esse ,maria1 do lucidas esse terras4 ,besides making a rude lunar chart1 he estimated the heights of some of the ring- mountains by measuring the distance from the terminator of their bright summit peaks1 when they were either coming into or passing out of sunlight2 and though his method was incapable of accuracy1 and his results consequently untrustworthy1 it served to demonstrate the immense altitude of these circumvallations1 and to show how greatly they exceed any mountains on the earth if the relative dimensions of the two globes are taken into consideration4 ,before the close of the century when selenography first became possible1 ,hevel of ,dantzig1 ,scheiner1 ,langrenus 7cosmographer to the ,king of ,spain71 ,riccioli1 the ,jesuit astronomer of ,bologna1 and ,dominic ,cassini1 the celebrated ,french astronomer1 greatly extended the knowledge of the moon's surface1 and published drawings of various phases1 and charts1 which1 though very rude and incomplete1 were a clear advance upon what ,galileo1 with his inferior optical means1 had been able to accomplish4 ,langrenus1 and after him ,hevel1 gave distinctive names to the various formations1 mainly derived from terrestrial physical features1 for which ,riccioli subsequently substituted those of philosophers1 mathematicians1 and other celebrities2 and ,cassini determined by actual measurement the relative position of many of the principal objects on the disc1 thus laying the foundation of an accurate system of lunar topography2 while the labours of ,t4 ,mayer and ,schroter in the last century1 and of ,lohrmann1 ,madler1 ,neison 7,nevill71 ,schmidt1 and other observers in the present1 have been mainly devoted to the study of the minuter detail of the moon and its physical characteristics4 ,as was manifest to the earliest telescopic observers1 its visible surface is clearly divisible into strongly contrasted areas1 differing both in colour and structural character4 ,somewhat less than half of what we see of it consists of comparatively level dark tracts1 some of them very many thousands of square miles in extent1 the monotony of whose dusky superficies is often unrelieved for great distances by any prominent object2 while the remainder1 everywhere manifestly brighter1 is not only more rugged and uneven1 but is covered to a much greater extent with numbers of quasi-circular formations1 differing widely in size1 classed as walled-plains1 ring-plains1 craters1 craterlets1 crater-cones1 c4 7the latter bearing a great outward resemblance to some terrestrial volcanoes71 and mountain ranges of vast proportions1 isolated hills1 and other features4 ,though nothing resembling sheets of water1 either of small or large extent1 have ever been detected on the surface1 the superficial resemblance1 in small telescopes1 of the large grey tracts to the appearance which we may suppose our terrestrial lakes and oceans would present to an observer on the moon1 naturally induced the early selenographers to term them ,maria1 or seas--a convenient name1 which is still maintained1 without1 however1 implying that these areas1 as we now see them1 are1 or ever were1 covered with water4 ,some1 however1 regard them as old sea-beds1 from which every trace of fluid1 owing to some unknown cause1 has vanished1 and that the folds and wrinkles1 the ridges1 swellings1 and other peculiarities of structure observed upon them1 represent some of the results of alluvial action4 ,it is1 of course1 possible1 and even probable1 that at a remote epoch in the evolution of our satellite these lower regions were occupied by water1 but that their surface1 as it now appears1 is actually this old sea-bottom1 seems to be less likely than that it represents the consolidated crust of some semi- fluid or viscous material 7possibly of a basaltic type7 which has welled forth from orifices or rents communicating with the interior1 and overspread and partially filled up these immense hollows1 more or less overwhelming and destroying many formations which stood upon them before this catastrophe took place4 ,though this1 like many other speculations of a similar character relating to lunar geology1 must remain1 at least for the present1 as a mere hypothesis2 indications of this partial destruction by some agency or other is almost everywhere apparent in those formations which border the so-called seas1 as1 for example1 ,fracastorius in the ,mare ,nectaris2 ,le ,monnier in the ,mare ,serenitatis2 ,pitatus and ,hesiodus1 on the south side of the ,mare ,nubium2 ,doppelmayer in the ,mare ,humorum1 and in many other situations2 while no observer can fail to notice innumerable instances of more or less complete obliteration and ruin among objects within these areas1 in the form of obscure rings 7mere scars on the surface71 dusky craters1 circular arrangements of isolated hills1 reminding one of the monoliths of a ,druidical temple2 all of which we are justified in concluding were at one time formations of a normal type4 ,it has been held by some selenologists --and ,schmidt appears to be of the number1--that1 seeing the comparative scarcity of large ring-plains and other massive formations on the ,maria1 these grey plains represent1 as it were1 a picture of the primitive surface of the moon before it was disturbed by the operations of interior forces2 but this view affords no explanation of the undoubted existence of the relics of an earlier lunar world beneath their smooth superficies4 ,,maria4--,leaving1 however1 these considerations for a more particular description of the ,maria1 it is clearly impossible1 in referring to their level relatively to the higher and brighter land surface of the moon1 to appeal to any hypsometrical standard4 ,all that is known in this respect is1 that they are invariably lower than the latter1 and that some sink to a greater depth than others1 or1 in other words1 that they do not all form a part of the same sphere4 ,though they are more or less of a greyish-slaty hue--some of them approximating very closely to that of the pigment known as ,payne's grey--the tone1 of course1 depends upon the angle at which the solar rays impinge on that particular portion of the surface under observation4 ,speaking generally1 they are1 as would follow from optical considerations1 conspicuously darker when viewed near the terminator1 or when the sun is either rising or setting upon them1 than under a more vertical angle of illumination4 ,but even when it is possible to compare their colour by eye-estimation under similar solar altitudes1 it is found that not only are some of the ,maria1 as a whole1 notably darker than others1 but nearly all of them exhibit local inequalities of hue1 which1 under good atmospheric and instrumental conditions1 are especially remarkable4 ,under such circumstances ,i have frequently seen the surface1 in many places covered with minute glittering points of light1 shining with a silvery lustre1 intermingled with darker spots and a network of streaks far too delicate and ethereal to represent in a drawing4 ,in addition to these contrasts and differences in the sombre tone of these extended plains1 many observers have remarked traces of a yellow or green tint on the surface of some of them4 ,for example1 the ,mare ,imbrium and the ,mare ,frigoris appear under certain conditions to be of a dirty yellow-green hue1 the central parts of the ,mare ,humorum dusky green1 and part of the ,mare ,serenitatis and the ,mare ,crisium light green1 while the ,palus ,somnii has been noted a golden-brown yellow4 ,to these may be added the district round ,taruntius in the ,mare ,foecunditatis1 and portions of other regions referred to in the catalogue1 where ,i have remarked a very decided sepia colour under a low sun4 ,it has been attempted to account for these phenomena by supposing the existence of some kind of vegetation2 but as this involves the presence of an atmosphere1 the idea hardly finds favour at the present time1 though perhaps the possibility of plant growth in the low-lying districts1 where a gaseous medium may prevail1 is not altogether so chimerical a notion as to be unworthy of consideration4 ,nasmyth and others suggest that these tints may be due to broad expanses of coloured volcanic material1 an hypothesis which1 if we believe the ,maria to be overspread with such matter1 and knowing how it varies in colour in terrestrial volcanic regions1 is more probable than the first4 ,anyway1 whether we consider these appearances to be objective1 or1 after all1 only due to purely physiological causes1 they undoubtedly merit closer study and investigation than they have hitherto received4 ,there are twenty-three of these dusky areas which have received distinctive names2 seventeen of them are wholly1 or in great part1 confined to the northern1 and to the south-eastern quarter of the southern hemisphere--the south-western quadrant being to a great extent devoid of them4 ,by far the largest is the vast ,oceanus ,procellarum1 extending from a high northern latitude to beyond latitude #aj deg4 in the south-eastern quadrant1 and1 according to ,schmidt1 with its bays and inflections1 occupying an area of nearly two million square miles1 or more than that of all the remaining ,maria put together4 ,next in order of size come the ,mare ,nubium1 of about one-fifth the superficies1 covering a large portion of the south-eastern quadrant1 and extending considerably north of the equator1 and the ,mare ,imbrium1 wholly confined to the northeastern quadrant1 and including an area of about #cdj1jjj square miles4 ,these are by far the largest lunar seas4 ,the ,mare ,foecunditatis1 in the western hemisphere1 the greater part of it lying in the south- western quadrant1 is scarcely half so big as the ,mare ,imbrium2 while the ,maria ,serenitatis and ,tranquilitatis1 about equal in area 7the former situated wholly north of the equator1 and the latter only partially extending south of it71 are still smaller4 ,the arctic ,mare ,frigoris1 some #ajj1jjj square miles in extent1 is the only remaining large sea1--the rest1 such as the ,mare ,vaporum1 the ,sinus ,medii1 the ,mare ,crisium1 the ,mare ,humorum1 and the ,mare ,humboldtianum1 are of comparatively small dimensions1 the ,mare ,crisium not greatly exceeding #gj1jjj square miles1 the ,mare ,humorum 7about the size of ,england7 #ej1jjj square miles1 while the ,mare ,humboldtianum1 according to ,schmidt1 includes only about #db1jjj square miles1 an area which is approached by some formations not classed with the ,maria4 ,this distinction1 speaking generally1 prevails among the ,maria1--those of larger size1 such as the ,oceanus ,procellarum1 the ,mare ,nubium1 and the ,mare ,foecunditatis1 are less definitely enclosed1 and1 like terrestrial oceans1 communicate with one another2 while their borders1 or1 if the term may be allowed1 their coast-line1 is often comparatively low and ill-defined1 exhibiting many inlets and irregularities in outline4 ,others1 again1 of considerable area1 as1 for example1 the ,mare ,serenitatis and the ,mare ,imbrium1 are bounded more or less completely by curved borders1 consisting of towering mountain ranges1 descending with a very steep escarpment to their surface3 thus in form and other characteristics they resemble immense wall-surrounded plains4 ,among the best examples of enclosed ,maria is the ,mare ,crisium1 which is considered by ,neison to be the deepest of all1 and the ,mare ,humboldtianum4 ,though these great plains are described as level1 this term must only be taken in a comparative sense4 ,no one who observes them when their surface is thrown into relief by the oblique rays of the rising or setting sun can fail to remark many low bubble-shaped swellings with gently rounded outlines1 shallow trough-like hollows1 and1 in the majority of them1 long sinuous ridges1 either running concentrically with their borders or traversing them from side to side4 ,though none of these features are of any great altitude or depth1 some of the ridges are as much as #gjj feet in height1 and probably in many instances the other elevations often rise to #aej feet or more above the low-lying parts of the plains on which they stand4 ,hence we may say that the ,maria are only level in the sense that many districts in the ,english ,midland counties are level1 and not that their surface is absolutely flat4 ,the same may be said as to their apparent smoothness1 which1 as is evident when they are viewed close to the terminator1 is an expression needing qualification1 for under these conditions they often appear to be covered with wrinkles1 flexures1 and little asperities1 which1 to be visible at all1 must be of considerable size4 ,in fact1 were it possible to examine them from a distance of a few miles1 instead of from a standpoint which1 under the most favourable circumstances1 cannot be reckoned at less than #cjj1 and this through an interposed aerial medium always more or less perturbed1 they would probably be described as rugged and uneven1 as some modern lava sheets4 ,,ridges4--,among the ,maria which exhibit the most remarkable arrangement of ridges is the ,mare ,humorum1 in the south-eastern quadrant4 ,here1 if it be observed under a rising sun1 a number of these objects will be seen extending from the region north of the ring-mountain ,vitello in long undulating lines1 roughly concentric with the western border of the sea1 and gradually diminishing in altitude as they spread out1 with many ramifications1 to a distance of #bjj miles or more towards the north4 ,at this stage of illumination they are strikingly beautiful in a good telescope1 reminding one of the ripple-marks left by the tide on a soft sandy beach4 ,like most other objects of their class1 they are very evanescent1 gradually disappearing as the sun rises higher in the lunar firmament1 and ultimately leaving nothing to indicate their presence beyond here and there a ghostly streak or vein of a somewhat lighter hue than that of the neighbouring surface4 ,the ,mare ,nectaris1 again1 in the south-western quadrant1 presents some fine examples of concentric ridges1 which are seen to the best advantage when the morning sun is rising on ,rosse1 a prominent crater north of ,fracastorius4 ,this sea is evidently concave in cross-section1 the central portion being considerably lower than the margin1 and these ridges appear to mark the successive stages of the change of level from the coast-line to the centre4 ,they suggest the caving in of the surface1 similar to that observed on a frozen pond or river1 where the cat's ice at the edge1 through the sinking of the water beneath1 is rent and tilted to a greater or less degree4 ,the ,mare ,serenitatis and the ,mare ,imbrium1 in the northern hemisphere1 are also remarkable for the number of these peculiar features4 ,they are very plentifully distributed round the margin and in other parts of the former1 which includes besides one of the longest and loftiest on the moon's visible surface--the great serpentine ridge1 first drawn and described nearly a hundred years ago by the famous selenographer1 ,schroter of ,lilienthal4 ,originating at a little crater under the north- east wall of great ring-plain ,posidonius1 it follows a winding course across the ,mare toward the south1 throwing out many minor branches1 and ultimately dies out under a great rocky promontory--the ,promontory ,acherusia1 at the western termination of the ,haemus range4 ,a comparatively low power serves to show the curious structural character of this immense ridge1 which appears to consist of a number of corrugations and folds massed together1 rising in places1 according to ,neison1 to a height of #gjj feet and more4 ,the ,mare ,imbrium also affords an example of a ridge1 which1 though shorter1 is nearly as prominent1 in that which runs from the bright little ring-plain ,piazzi ,smyth towards the west side of ,plato4 ,the region round ,timocharis and other quarters of the ,mare are likewise traversed by very noteworthy features of a similar class4 ,the ,oceanus ,procellarum also presents good instances of ridges in the marvellous ramifications round ,encke1 ,kepler1 and ,marius1 and in the region north of ,aristarchus and ,herodotus4 ,perhaps the most perfect examples of surface swellings are those in the ,mare ,tranquilitatis1 a little east of the ring-plain ,arago1 where there are two nearly equal circular mounds1 at least ten miles in diameter1 resembling tumuli seen from above4 ,similar1 but more irregular1 objects of a like kind are very plentiful in many other quarters4 ,it is a suggestive peculiarity of many of the lunar ridges1 both on the ,maria and elsewhere1 that they are very generally found in association with craters of every size4 ,illustrations of this fact occur almost everywhere4 ,frequently small craters are found on the summits of these elevations1 but more often on their flanks and near their base4 ,where a ridge suddenly changes its direction1 a crater of some prominence generally marks the point1 often forming a node1 or crossing-place of other ridges1 which thus appear to radiate from it as a centre4 ,sometimes they intrude within the smaller ring-mountains1 passing through gaps in their walls as1 for example1 in the cases of ,madler1 ,lassell1 c4 ,various hypotheses have been advanced to account for them4 ,the late ,professor ,phillips1 the geologist1 who devoted much attention to the telescopic examination of the physical features of the moon1 compared the lunar ridges to long1 low1 undulating mounds1 of somewhat doubtful origin1 called kames in ,scotland1 and eskers in ,ireland1 where on the low central plain they are commonly found in the form of extended banks 7mainly of gravel71 with more or less steep sides1 rising to heights of from #bj to #gj feet4 ,they are sometimes only a few yards wide at the top1 while in other places they spread out into large humps1 having circular or oval cavities on their summits1 #ej or #fj yards across1 and as much as #dj feet deep4 ,like the lunar ridges1 they throw out branches and exhibit many breaches of continuity4 ,by some geologists they are supposed to represent old submarine banks formed by tidal currents1 like harbour bars1 and by others to be glacial deposits2 in either case1 to be either directly or indirectly due to alluvial action4 ,their outward resemblance to some of the ridges on the moon is unquestionable2 and if we could believe that the ,maria1 as we now see them1 are dried-up sea-beds1 it might be concluded that these ridges had a similar origin2 but their close connection with centres of volcanic disturbance1 and the numbers of little craters on or near their track1 point to the supposition that they consist rather of material exuded from long-extending fissures in the crust of the seas1 and in other surfaces where they are superimposed4 ,this conjecture is rendered still more probable by the fact that we sometimes find the direction of clefts 7which are undoubted surface cracks7 prolonged in the form of long narrow ridges or of rows of little hillocks4 ,we are1 however1 not bound to assume that all the manifold corrugations observed on the lunar plains are due to one and the same cause2 indeed1 it is clear that some are merely the outward indications of sudden drops in the surface1 as in the case of the ridges round the western margin of the ,mare ,nectaris1 and in other situations1 where subsidence is manifested by features assuming the outward aspect of ordinary ridges1 but which are in reality of a very different structural character4 ,the ,maria1 like almost every other part of the visible surface1 abound in craters of a minute type1 which are scattered here and there without any apparent law or ascertained principle of arrangement4 ,seeing how imperfect is our acquaintance with even the larger objects of this class1 it is rash to insist on the antiquity or permanence of such diminutive objects1 or to dogmatise about the cessation of lunar activity in connection with features where the volcanic history of our globe1 if it is of any value as an analogue1 teaches us it is most likely to prevail4 ,most observers will agree with ,schmidt1 that observations and drawings of objects on the sombre depressed plains of the moon are easier and pleasanter to make than on the dazzling highlands1 and that the lunar sea is to the working selenographer like an oasis in the desert to the traveller--a relief in this case1 however1 not to an exhausted body1 but to a weary eye4 ,,ring-,,mountains1 ,,craters1 ,c4--,it is these objects1 in their almost endless variety and bewildering number1 which1 more than any others1 give to our satellite that marvellous appearance in the telescope which since the days of ,galileo has never failed to evoke the astonishment of the beholder4 ,however familiar we may be with the lunar surface1 we can never gaze on these extraordinary formations1 whether massed together apparently in inextricable confusion1 or standing in isolated grandeur1 like ,copernicus1 on the grey surface of the plains1 without experiencing1 in a scarcely diminished degree1 the same sensation of wonder and admiration with which they were beheld for the first time4 ,although the attempt to bring all these bizarre forms under a rigid scheme of classification has not been wholly successful1 their structural peculiarities1 the hypsometrical relation between their interior and the surrounding district1 their size1 and the character of their circumvallation1 the dimensions of their cavernous opening as compared with that of the more or less truncated conical mass of matter surrounding it1 all afford a basis for grouping them under distinctive titles1 that are not only convenient to the selenographer1 but which undoubtedly represent1 as a rule1 actual diversities in their origin and physical character4 ,these distinguishing titles1 as adopted by ,schroter1 ,lohrmann1 and ,madler1 and accepted by subsequent observers1 are ,,walled-,,plains1 ,,mountain ,,rings1 ,,ring-,,plains1 ,,craters1 ,,crater-,,cones1 ,,craterlets1 ,,crater-,,pits1 ,,depressions4 ,,walled-,,plains4--,these formations1 approximating more or less to the circular form1 though frequently deviating considerably from it1 are among the largest enclosures on the moon4 ,they vary from upwards of #aej to #fj miles or under in diameter1 and are often encircled by a complex rampart of considerable breadth1 rising in some instances to a height of #ab1jjj feet or more above the enclosed plain4 ,this rampart is rarely continuous1 but is generally interrupted by gaps1 crossed by transverse valleys and passes1 and broken by more recent craters and depressions4 ,as a rule1 the area within the circumvallation 7usually termed the floor7 is only slightly1 if at all1 lower than the region outside3 it is very generally of a dusky hue1 similar to that of the grey plains or ,maria1 and1 like them1 is usually variegated by the presence of hills1 ridges1 and craters1 and is sometimes traversed by delicate furrows1 termed clefts or rills4 ,ptolemaeus1 in the third quadrant1 and not far removed from the centre of the disc1 may be taken as a typical example of the class4 ,here we have a vast plain1 #aae miles from side to side1 encircled by a massive but much broken wall1 which at one peak towers more than #ijjj feet above a level floor1 which includes details of a very remarkable character4 ,the adjoining ,alphonsus is another1 but somewhat smaller1 object of the same type1 as are also ,albategnius1 and ,arzachel2 and ,plato1 in a high northern latitude1 with its noble many-peaked rampart and its variable steel-grey interior4 ,grimaldi1 near the eastern limb 7perhaps the darkest area on the moon71 ,schickard1 nearly as big1 on the south- eastern limb1 and ,bailly1 larger than either 7still farther south in the same quadrant71 although they approach some of the smaller seas in size1 are placed in the same category4 ,the conspicuous central mountain1 so frequently associated with other types of ringed enclosures1 is by no means invariably found within the walled-plains2 though1 as in the case of ,petavius1 ,langrenus1 ,gassendi1 and several other noteworthy examples1 it is very prominently displayed4 ,the progress of sunrise on all these objects affords a magnificent spectacle4 ,very often when the rays impinge on their apparently level floor at an angle of from #a deg4 to #b deg41 it is seen to be coarse1 rough grained1 and covered with minute elevations1 although an hour or so afterwards it appears as smooth as glass4 ,although it is a distinguishing characteristic that there is no great difference in level between the outside and the inside of a walled-plain1 there are some very interesting exceptions to this rule1 which are termed by ,schmidt ,transitional forms4 ,among these he places some of the most colossal formations1 such as ,clavius1 ,maurolycus1 ,stofler1 ,janssen1 and ,longomontanus4 ,the first1 which may be taken as representative of the class 7well known to observers as one of the grandest of lunar objects71 has a deeply sunken floor1 fringed with mountains rising some #ab1jjj feet above it1 though they scarcely stand a fourth of this height above the plain on the west1 which ascends with a very gentle gradient to the summit of the wall4 ,hence the contrast between the shadows of the peaks of the western wall on the floor at sunrise1 and of the same peaks on the region west of the border at sunset is very marked4 ,in ,gassendi1 ,phocylides1 and ,wargentin we have similar notable departures from the normal type4 ,the floor of the former on the north stands #bjjj feet above the ,mare ,humorum4 ,in ,phocylides1 probably through faulting1 one portion of the interior suddenly sinks to a considerable depth below the remainder2 while the very abnormal ,wargentin has such an elevated floor1 that1 when viewed under favourable conditions1 it reminds one of a shallow oval tray or dish filled with fluid to the point of overflowing4 ,these examples1 very far from being exhaustive1 will be sufficient to show that the walled-plains exhibit noteworthy differences in other respects than size1 height of rampart1 or included detail4 ,still another peculiarity1 confined1 it is believed1 to a very few1 may be mentioned1 viz41 convexity of floor1 prominently displayed in ,petavius1 ,mersenius1 and ,hevel4 ,,mountain ,,rings4--,these objects1 usually encircled by a low and broken border1 seldom more than a few hundred feet in height1 are closely allied to the walled-plains4 ,they are more frequently found on the ,maria than elsewhere4 ,in some cases the ring consists of isolated dark sections1 with here and there a bright mass of rock interposed2 in others1 of low curvilinear ridges1 forming a more or less complete circumvallation4 ,they vary in size from #fj or #gj miles to #ae miles and less4 ,the great ring north of ,flamsteed1 #fj miles across1 is a notable example2 another lies west of it on the north of ,wichmann2 while a third will be found south- east of ,encke2--indeed1 the ,mare ,procellarum abounds in objects of this type4 ,the curious formation on the ,mare ,imbrium immediately south of ,plato 7called ,newton by ,schroter71 may be placed in this category1 as may also many of the low dusky rings of much smaller dimensions found in many quarters of the ,maria4 ,as has been stated elsewhere1 these features have the appearance of having once been formations of a much more prominent and important character1 which have suffered destruction1 more or less complete1 through being partially overwhelmed by the material of the seas4 ,,ring-,,plains4--,these are by far the most numerous of the ramparted enclosures of the moon1 and though it is occasionally difficult to decide in which class1 walled-plain or ring-plain1 some objects should be placed1 yet1 as a rule1 the difference between the structural character of the two is abundantly obvious4 ,the ring-plains vary in diameter from sixty to less than ten miles1 and are far more regular in outline than the walled-plains4 ,their ramparts1 often very massive1 are more continuous1 and fall with a steep declivity to a floor almost always greatly depressed below the outside region4 ,the inner slopes generally display subordinate heights1 called terraces1 arranged more or less concentrically1 and often extending in successive stages nearly down to the interior foot of the wall4 ,with the intervening valleys1 these features are very striking objects when viewed under good conditions with high powers4 ,in some cases they may possibly represent the effects of the slipping of the upper portions of the wall1 from a want of cohesiveness in the material of which it is composed2 but this hardly explains why the highest terrace often stands nearly as high as the rampart4 ,nasmyth1 in his eruption hypothesis1 suggests that in such a case there may have been two eruptions from the same vent2 one powerful1 which formed the exterior circle1 and a second1 rather less powerful1 which has formed the interior circle4 ,ultimately1 however1 coming to the conclusion that terraces1 as a rule1 are not due to any such freaks of the eruption1 he ascribes them to landslips4 ,in any case1 we can hardly imagine that material standing at such a high angle of inclination as that forming the summit ridge of many of the ring-plains would not frequently slide down in great masses1 and thus form irregular plateaus on the lower and flatter portions of the slope2 but this fails to explain the symmetrical arrangement of the concentric terraces and intermediate valleys4 ,the inner declivity of the north-eastern wall of ,plato exhibits what to all appearance is an undoubted landslip1 as does also that of ,hercules on the northern side1 and numerous other cases might be adduced2 but in all of them the appearance is very different from that of the true terrace4 ,the glacis1 or outer slope of a ring-plain1 is invariably of a much gentler inclination than that which characterises the inner declivity3 while the latter very frequently descends at an angle varying from #fj deg4 to #ej deg4 at the crest of the wall1 to from #aj deg4 to #b deg4 at the bottom1 where it meets the floor2 the former extends for a great distance at a very flat gradient before it sinks to the general level of the surrounding country4 ,it differs likewise from the inner descent1 in the fact that1 though often traversed by valleys1 intersected by deep gullies and irregular depressions1 and covered with humpy excrescences and craters1 it is only rarely that any features comparable to the terraces1 usually present on the inner escarpment1 can be traced upon it4 ,elongated depressions of irregular outline1 and very variable in size and depth1 are frequently found on the outer slopes of the border4 ,some of them consist of great elliptical or sub-circular cavities1 displaying many expansions and contractions1 called pockets1 and suggesting the idea that they were originally distinct cup-shaped hollows1 which from some cause or other have coalesced like rows of inosculating craters4 ,while many of these features are so deep that they remain visible for a considerable time under a low sun1 others1 though perhaps of greater extent1 vanish in an hour or so4 ,as in the case of the walled-plains1 the ramparts of the ring-plains exhibit gaps and are broken by craters and depressions1 but to a much less extent4 ,often the lofty crest1 surmounted by aiguilles or by blunter peaks1 towering in some cases to nearly double its altitude above the interior1 is perfectly continuous 7like ,copernicus71 or only interrupted by narrow passes4 ,it is a suggestive circumstance that gaps1 other than valleys1 are almost invariably found either in the north or south walls1 or in both1 and seldom in other positions4 ,the buttress1 or long-extending spur1 is a feature frequently associated with the ring- plain rampart1 as are also numbers of what1 for the lack of a better name1 must be termed little hillocks1 which generally radiate in long rows from the outer foot of the slope4 ,the spurs usually abut on the wall1 and1 either spreading out like the sticks of a fan or running roughly parallel to each other1 extend for long distances1 gradually diminishing in height and width till they die out on the surrounding surface4 ,they have been compared to lava streams1 which those round ,aristillus1 ,aristoteles1 and on the flank of ,clavius a1 certainly somewhat resemble1 though1 in the two former instances1 they are rather comparable to immense ridges4 ,in addition to the above1 the spurs radiating from the south-eastern rampart of ,condamine and the long undulating ridges and rows of hillocks running from ,cyrillus over the eastern glacis of ,theophilus1 may be named as very interesting examples4 ,neison and some other selenographers place in a distinct class certain of the smaller ring-plains which usually have a steeper outer slope1 and are supposed to present clearer indications of a volcanic origin than the ring-plains1 terming them ,crater-plains4 ,,craters4--,under this generic name is placed a vast number of formations exhibiting a great difference in size and outward characteristics1 though generally 7under moderate magnification7 of a circular or sub-circular shape4 ,their diameter varies from #ae miles or more to #c1 and even less1 and their flanks rise much more steeply to the summit1 which is seldom very lofty1 than those of the ring-plains1 and fall more gradually to the floor4 ,there is no portion of the moon in which they do not abound1 whether it be on the ramparts1 floors1 and outer slopes of walled and ring plains1 the summits and escarpments of mountain ranges1 amid the intricacies of the highlands1 or on the grey surface of the ,maria4 ,in many instances they have a brighter and newer aspect than the larger formations1 often being the most brilliant points on their walls1 when they are found in this position4 ,very frequently too they are not only very bright themselves1 but stand on bright areas1 whose borders are generally concentric with them1 which shine with a glistening lustre1 and form a kind of halo of light around them4 ,euclides and ,bessarion ,a1 and the craters east of ,landsberg1 are especially interesting examples4 ,it seems not improbable that these areas may represent deposits formed by some kind of matter ejected from the craters1 but whether of ancient or modern date1 it is1 of course1 impossible to determine4 ,future observers will perhaps be in a better position to decide the question without cavil1 if such eruptions should again take place4 ,like the larger enclosures1 these smaller objects frequently encroach upon each other-- crater-ring overlapping crater-ring1 as in the case of ,thebit1 where a large crater1 which has interfered with the continuity of the east wall1 has1 in its turn1 been disturbed by a smaller crater on its own east wall4 ,the craters in many cases1 possibly in the majority if we could detect them1 have central mountains1 some of them being excellent tests for telescopic definition--as1 for example1 the central peaks of ,hortensius1 ,bessarion1 and that of the small crater just mentioned on the east wall of ,thebit ,a4 ,a tendency to a linear arrangement is often displayed1 especially among the smaller class1 as is also their occurrence in pairs4 ,,crater-,,cones4--,these objects1 plentifully distributed on the lunar surface1 are especially interesting from their outward resemblance to the parasitic cones found on the flanks of terrestrial volcanoes 7,etna1 for instance74 ,in the larger examples it is occasionally possible to see that the interiors are either inverted cones without a floor1 or cup-shaped depressions on the summit of the object4 ,frequently1 however1 they are so small that the orifice can only be detected under oblique illumination4 ,under a high sun they generally appear as white spots1 more or less ill- defined1 as on the floors of ,archimedes1 ,fracastorius1 ,plato1 and many other formations1 which include a great number1 all of which are probably crater cones1 although only a few have been seen as such4 ,it is a significant fact that in these situations they are always found to be closely associated with the light streaks which traverse the interior of the formations1 standing either on their surface or close to their edges4 ,the instrumental and meteorological requirements necessary for a successful scrutiny of the smallest type of these features1 are beyond the reach of the ordinary observer in this country1 as they demand direct observation in large telescopes under the best atmospheric conditions4 ,some years ago ,dr4 ,klein of ,cologne called attention to some very interesting types of crater-cones1 which may be found on certain dark or smoky-grey areas on the moon4 ,these1 he considers1 may probably represent active volcanic vents1 and urges that they should be diligently examined and watched by observers who possess telescopes adequate to the task4 ,the most noteworthy examples of these objects are in the following positions3--7#a7 ,west of a prominent ridge running from ,beaumont to the west side of ,theophilus1 and about midway between these formations2 7#b7 in the ,mare ,vaporum1 south of ,hyginus2 7#c7 on the floor of ,werner1 near the foot of the north wall2 7#d7 under the east wall of ,alphonsus1 on the dusky patch in the interior2 7#e7 on the south side of the floor of ,atlas4 ,i have frequently described elsewhere with considerable detail the telescopic appearance of these features under various phases1 and have pointed out that though large apertures and high powers are needed to see these cones to advantage1 the dusky areas1 easily traced on photograms1 might be usefully studied by observers with smaller instruments1 as if they represent the ejecta from the crater-cones which stand upon them1 changes in their form and extent could very possibly be detected4 ,in addition to those already referred to1 a number of mysterious dark spots were discovered by ,schmidt in the dusky region about midway between ,copernicus and ,gambart1 which ,klein describes as perforated like a sieve with minute craters4 ,a short distance south-west of ,copernicus stands a bright crater-cone surrounded by a grey nimbus1 which may be classed with these objects4 ,it is well seen under a high light1 as indeed is the case with most of these features4 ,,craterlets1 ,,crater-,,pits4--,to a great extent the former term is needless and misleading1 as the so-called craters merge by imperceptible gradations into very minute objects1 as small as half a mile in diameter1 and most probably1 if we could more accurately estimate their size1 still less4 ,the crater-pit1 however1 has well-marked peculiarities which distinguish it from all other types1 such as the absence of a distinguishable rim and extreme shallowness4 ,they appear to be most numerous on the high-level plains and plateaus in the south-western quadrant1 and may be counted by hundreds under good atmospheric conditions on the outer slopes of ,walter1 ,clavius1 and other large enclosures4 ,in these positions they are often so closely aggregated that1 as ,nasmyth remarks1 they remind one of an accumulation of froth4 ,even in an #h #a_/b inch reflector ,i have frequently seen the outer slope of the large ring-plain on the north-western side of ,vendelinus1 so perforated with these objects that it resembled pumice or vesicular lava1 many of the little holes being evidently not circular1 but square shaped and very irregular4 ,the interior of ,stadius and the region outside abounds in these minute features1 but the well-known crater-row between this formation and ,copernicus seems rather to consist of a number of inosculating crater-cones1 as they stand very evidently on a raised bank of some altitude4 ,,mountain ,,ranges1 ,,isolated ,,mountains1 c4--,the more massive and extended mountain ranges of the moon are found in the northern hemisphere1 and 7what is significant7 in that portion of it which exhibits few indications of other superficial disturbances4 ,the most prominently developed systems1 the ,alps1 the ,caucasus1 and the ,apennines1 forming a mighty western rampart to the ,mare ,imbrium and giving it all the appearance of a vast walled plain1 present few points of resemblance to any terrestrial chain4 ,the former include many hundred peaks1 among which1 ,mont ,blanc rises to a height of #ab1jjj feet1 and a second1 some distance west of ,plato1 to nearly as great an altitude2 while others1 ranging from #ejjj to #hjjj feet1 are common4 ,they extend in a south-west direction from ,plato to the ,caucasus1 terminating somewhat abruptly1 a little west of the central meridian1 in about ,n4 lat4 #db deg4 ,one of the most interesting features associated with this range is the so-called great ,alpine valley1 which cuts through it west of ,plato4 ,the ,caucasus consist of a massive wedge-shaped mountain land1 projecting southwards1 and partially dividing the ,mare ,imbrium from the ,mare ,serenitatis1 both of which they flank4 ,though without peaks so lofty as those pertaining to the ,alps1 there is one1 immediately east of the ring-plain ,calippus1 which1 towering to #ai1jjj feet1 surpasses any of which the latter system can boast4 ,the ,apennines1 however1 are by far the most magnificent range on the visible surface1 including as they do some #cjjj peaks1 and extending in an almost continuous curve of more than #djj miles in length from ,mount ,hadley1 on the north1 to the fine ring-plain ,eratosthenes1 which forms a fitting termination1 on the south4 ,the great headland ,mount ,hadley rises more than #ae1jjj feet1 while a neighbouring promontory on the south-east of it is fully #ad1jjj feet1 and another1 close by1 is still higher above the ,mare4 ,mount ,huygens1 again1 in ,n4 lat4 #bj deg41 and the square-shaped mass ,mount ,wolf1 near the southern end of the chain1 include peaks standing #ah1jjj and #ab1jjj feet respectively above the plain1 to which their flanks descend with a steep declivity4 ,the counterscarp of the ,apennines1 in places #afj miles in width from east to west1 runs down to the ,mare ,vaporum with a comparatively gentle inclination4 ,it is everywhere traversed by winding valleys of a very intricate type1 all trending towards the south-west1 and includes some bright craters and mountain-rings4 ,the ,carpathians1 forming in part the southern border of the ,mare ,imbrium1 extend for a length of more than #ahj miles eastward of ,e41 long4 #af deg41 and1 embracing the ring-plain ,gay- ,lussac1 terminate west of ,mayer4 ,they present a less definite front to the ,mare than the ,apennines1 and are broken up and divided by irregular valleys and gaps2 their loftiest peak1 situated on a very projecting promontory north-west of ,mayer1 rising to a height of #gjjj feet4 ,notwithstanding their comparatively low altitude1 the region they occupy forms a fine telescopic picture at lunar sunrise4 ,the ,sinus ,iridum highlands1 bordering the beautiful bay on the north-east side of the ,mare ,imbrium1 rank among the loftiest and most intricate systems on the moon1 and1 like the ,apennines1 present a steep face to the grey plain from which they rise1 though differing from them in other respects4 ,they include many high peaks1 the loftiest1 in the neighbourhood of the ring- plain ,sharp1 rising #ae1jjj feet4 ,there are probably some still higher mountains in the vicinity1 but the difficulties attending their measurement render it impossible to determine their altitude with any approach to accuracy4 ,the ,taurus ,mountains extend from the west side of the ,mare ,serenitatis1 near ,le ,monnier and ,littrow1 in a north-westerly direction towards ,geminus and ,berselius1 bordering the west side of the ,lacus ,somniorum4 ,they are a far less remarkable system than any of the preceding1 and consist rather of a wild irregular mountain region than a range4 ,in the neighbourhood of ,berselius are some peaks which1 according to ,neison1 cannot be less than #aj1jjj feet in height4 ,on the north side of the ,mare ,imbrium1 east of ,plato1 there is a beautiful narrow range of bright outlying heights1 called the ,teneriffe ,mountains1 which include many isolated objects of considerable altitude1 one of the loftiest rising about #hjjj feet4 ,farther towards the east lies another group of a very similar character1 called the ,straight ,range1 from its linear regularity4 ,it extends from west to east for a distance of about #fj miles1 being a few miles shorter than the last1 and includes a peak of #fjjj feet4 ,the ,harbinger ,mountains4--,a remarkable group1 north-west of ,aristarchus1 including some peaks as high as #gjjj feet1 and other details noticed in the catalogue4 ,the above comprise all the mountain ranges in the northern hemisphere of any prominence1 or which have received distinctive names1 except the ,hercynian ,mountains1 on the north-east limb1 east of the walled plain ,otto ,struve4 ,these are too near the edge to be well observed1 but1 from what can be seen of them1 they appear to abound in lofty peaks1 and to bear more resemblance to a terrestrial chain than any which have yet been referred to4 ,the mountain systems of the southern hemisphere1 except the ranges visible on the limb1 are far less imposing and remarkable than those just described4 ,the ,pyrenees1 on the western side of the ,mare ,nectaris1 extend in a meridional direction for nearly #aij miles1 and include a peak east of ,guttemberg of nearly #ab1jjj feet1 and are traversed in many places by fine valleys4 ,the ,altai ,mountains form a magnificent chain1 #bge miles in length1 commencing on the outer eastern slope of ,piccolomini1 and following a tolerably direct north-east course1 with a few minor bendings1 to the west side of ,fermat1 where they turn more towards the north1 ultimately terminating about midway between ,tacitus and ,catherina4 ,the region situated on the south-east is a great table-land1 without any prominent features1 rising gently towards the mountains1 which shelve steeply down to an equally barren expanse on the north-west1 to which they present a lofty face1 having an average altitude of about #fjjj feet4 ,the loftiest peak1 over #ac1jjj feet1 rises west of ,fermat4 ,the ,riphaean ,mountains1 a remarkably bright group1 occupying an isolated position in the ,mare ,procellarum south of ,landsberg1 and extending for more than #ajj miles in a meridional direction4 ,they are most closely aggregated at a point nearly due west of ,euclides1 from which they throw off long-branching arms to the north and south1 those on the north bifurcating and gradually sinking to the level of the plain4 ,the loftiest peaks are near the extremity of this section1 one of them rising to #cjjj feet4 ,two bright craters are associated with these mountains1 one nearly central1 and the other south of it4 ,the ,percy ,mountains4--,this name is given to the bright highlands extending east of ,gassendi towards ,mersenius1 forming the north-eastern border of the ,mare ,humorum4 ,they abound in minute detail--bright little mountains and ridges--and include some clefts pertaining to the ,mersenius rill-system2 but their most noteworthy feature is the long bright mountain-arm1 branching out from the eastern wall of ,gassendi1 and extending for more than #ej miles towards the south-east4 ,the principal ranges on the limb are the ,leibnitz ,mountains1 extending from ,s4 lat4 #gj deg4 on the west to ,s4 lat4 #hj deg4 on the east limb4 ,they include some giant peaks and plateaus1 noteworthy objects in profile1 some of which1 according to ,schroter and ,madler1 rise to #bf1jjj feet4 ,the ,dorfel ,mountains1 between ,s4 lat4 #hj deg4 and #eg deg4 on the eastern limb1 include1 if ,schroter's estimate is correct1 three peaks which exceed #bf1jjj feet4 ,on the eastern limb1 between ,s4 lat4 #ce deg4 and #ah deg41 extend the ,rook ,mountains1 which have peaks1 according to ,schroter1 as high as #be1jjj feet4 ,next in order come the ,cordilleras1 which extend to ,s4 lat4 #h deg41 and the ,d',alembert ,mountains1 lying east of ,rocca and ,grimaldi1 closely associated with them1 and probably part of the same system4 ,some of the peaks approach #bj1jjj feet4 ,in addition to these mountain ranges there are others less prominent on the limb in the northern hemisphere1 which have not been named4 ,,isolated ,,mountains are very numerous in different parts of the moon1 the most remarkable are referred to in the appendix4 ,many remain unnamed4 ,,clefts ,,or ,,rills4--,though ,fontenelle1 in his ,entretiens sur la ,pluralite des ,mondes1 informs his pupil1 the ,marchioness1 that ,m4 ,cassini discovered in the moon something which separates1 then reunites1 and finally loses itself in a cavity1 which from its appearance seemed to be a river1 it can hardly be supposed that what the ,french astronomer saw1 or fancied he saw1 with the imperfect telescopes of that day1 was one of the remarkable and enigmatical furrows termed clefts or rills1 first detected by the ,hanoverian selenographer ,schroter2 who1 on ,october #g1 #aghg1 discovered the very curious serpentine cleft near ,herodotus1 having a few nights before noted for the first time the great ,alpine valley west of ,plato1 once classed with the clefts1 though it is an object of a very different kind4 ,between #aghg and #agig ,schroter found ten rills2 but twenty years elapsed before an addition was made to this number by the discoveries of ,gruithuisen1 and1 a short time after1 by those of ,lohrmann1 who in twelve months 7#ahbc-bd7 detected seventy4 ,kinau1 ,madler1 and finally ,schmidt1 followed1 till1 in #ahff1 when the latter published his work1 ,ueber ,rillen auf dem ,monde1 the list was thus summarised3-- ,in the #ast or ,n4,w4 quadrant #abg rills ,in the #bnd or ,n4,e4 quadrant #ge rills ,in the #crd or ,s4,e4 quadrant #ada rills ,in the #dth or ,s4,w4 quadrant #hb rills or #dbe in all4 ,since the date of this book the number of known rills has been more than doubled2 in fact1 scarcely a lunation passes without new discoveries being made4 ,the significance of the word rille in ,german1 a groove or furrow1 describes with considerable accuracy the usual appearance of the objects to which it is applied1 consisting as they do of long narrow channels1 with sides more or less steep1 and sometimes vertical4 ,they often extend for hundreds of miles in approximately straight lines over portions of the moon's surface1 frequently traversing in their course ridges1 craters1 and even more formidable obstacles1 without any apparent check or interruption1 though their ends are sometimes marked by a mound or crater4 ,their length ranges from ten or twelve to three hundred miles or more 7as in the great ,sirsalis rill71 their breadth1 which is very variable within certain limits1 from less than half a mile to more than two1 and their depth 7which must necessarily remain to a great extent problematical7 from #ajj to #djj yards4 ,they exhibit in the telescope a gradation from somewhat coarse grooves1 easily visible at suitable times in very moderately sized instruments1 to striae so delicate as to require the largest and most perfect optical means and the best atmospheric conditions to be glimpsed at all4 ,viewed under moderate amplification1 the majority of rills resemble deep canal-like channels with roughly parallel sides1 displaying occasionally local irregularities1 and fining off to invisibility at one or both ends4 ,but1 if critically scrutinised in the best observing weather with high powers1 the apparent evenness of their edges entirely disappears1 and we find that the latter exhibit indentations1 projections1 and little flexures1 like the banks of an ordinary stream or rivulet1 or1 to use a very homely simile1 the serrated edges and little jagged irregularities of a biscuit broken across4 ,in some cases we remark crateriform hollows or sudden expansions in their course1 and deep sinuous ravines1 which render them still more unsymmetrical and variable in breadth4 ,with regard to their distribution on the lunar surface2 they are found in almost every region1 but perhaps not so frequently on the surface of the ,maria as elsewhere1 though1 as in the case of the ,triesnecker and other systems1 they often abound in the neighbourhood of disturbed regions in these plains1 and in many cases along their margins1 as1 for example1 the ,gassendi-,mersenius and the ,sabine-,ritter groups4 ,the interior of walled plains are frequently intersected by them1 as in ,gassendi1 where nearly forty1 more or less delicate examples1 have been seen2 in ,hevel1 where there is a very interesting system of crossed clefts1 and within ,posidonius4 ,if we study any good modern lunar map1 it is evident how constantly they appear near the borders of mountain ranges1 walled-plains1 and ring-plains2 as1 for instance1 at the foot of the ,apennines2 near ,archimedes1 ,aristarchus1 ,ramsden1 and in many other similar positions4 ,rugged highlands also are often traversed by them1 as in the case of those lying west of ,le ,monnier and ,chacornac1 and in the region west of the ,mare ,humorum4 ,it may be here remarked1 however1 as a notable fact1 that the neighbourhood of the grandest ring-mountain on the moon1 ,copernicus1 is1 strange to say1 devoid of any features which can be classed as true clefts1 though it abounds in crater-rows4 ,the intricate network of rills on the west of ,triesnecker1 when observed with a low power1 reminds one of the wrinkles on the rind of an orange or on the skin of a withered apple4 ,gruithuisen1 describing the rill-traversed region between ,agrippa and ,hyginus1 says that it has quite the look of a ,dutch canal map4 ,in the subjoined catalogue many detailed examples will be given relating to the course of these mysterious furrows2 how they occasionally traverse mountain arms1 cut through1 either completely or partially 7as in ,ramsden71 the borders of ring-plains and other enclosures1 while not unfrequently a small mound or similar feature appears to have caused them to swerve suddenly from their path1 as in the case of the ,ariadaeus cleft1 and in that of one member of the ,mercator-,campanus system4 ,of the actual nature of the lunar rills we are1 it must be confessed1 supremely ignorant4 ,with some of the early observers it was a very favourite notion that they are artificial works1 constructed presumably by ,kepler's sub-volvani1 or by other intelligences4 ,there is perhaps some excuse to be made for the freaks of an exuberant fancy in regard to objects which1 if we ignore for a moment their enormous dimensions1 judged by a terrestrial standard1 certainly have1 in their apparent absence of any physical relation to neighbouring objects1 all the appearance of being works of art rather than of nature4 ,the keen-sighted and very imaginative ,gruithuisen believed that in some instances they represent roads cut through interminable forests1 and in others the dried-up beds of once mighty rivers4 ,his description of the ,triesnecker rill-system reads like a page from a geographical primer4 ,a portion of it is compared to the river ,po1 and he traces its course mile by mile up to the delta at its place of disemboguement into the ,mare ,vaporum4 ,from the position of some rills with respect to the contour of the surrounding country1 it is evident that if water were now present on the moon1 they1 being situated at the lowest level1 would form natural channels for its reception2 but the exceptions to this arrangement are so numerous and obvious1 that the idea may be at once dismissed that there is any analogy between them and our rivers4 ,the eminent selenographer1 the late ,w4,k4 ,birt1 compared many of them to inverted river-beds from the fact that1 as often as not1 they become broader and deeper as they attain a higher level4 ,the branches resemble rivers more frequently than the main channels2 for they generally commence as very fine grooves1 and1 becoming broader and broader1 join them at an acute angle4 ,an attempt again has been made to compare the lunar clefts with those vast gorges1 the marvellous results of aqueous action1 called canyons1 which attain their greatest dimensions in ,north ,america2 such as the ,great ,canyon of the ,colorado1 which is at least #cjj miles in length1 and in places #bjjj yards in depth1 with perpendicular or even overhanging sides2 but the analogy1 at first sight specious1 utterly breaks down under closer examination4 ,some selenographers consider them to consist of long-extending rows of confluent craters1 too minute to be separately distinguished1 and to be thus due to some kind of volcanic action4 ,this is undoubtedly true in many instances1 for almost every lunar region affords examples of crater- rows merging by almost imperceptible gradations into cleft-like features1 and crater-rows of considerable size resemble clefts under low powers4 ,still it seems probable that the greater number of these features are immense furrows or cracks in the surface and nothing more2 for the higher the magnifying power employed in their examination1 the less reason there is to object to this description4 ,dr4 ,klein of ,cologne believes that rills of this class are due to the shrinkage of parts of the moon's crust1 and that they are not as a rule the result of volcanic causes1 though he admits that there may be some which have a seismic origin4 ,no good reason has as yet been given for the fact that they so frequently cross small craters and other objects in their course1 though it has been suggested that the route followed by a rill from crater to crater in these instances may be a line of least surface resistance1 an explanation far from being satisfactory4 ,whether variations in the visibility of lunar details1 when observed under apparently similar conditions1 actually occur from time to time from some unknown cause1 is one of those vexed questions which will only be determined when the moon is systematically studied by experienced observers using the finest instruments at exceptionally good stations2 but no one who examines existing records of observations of rills by ,gruithuisen1 ,lohrmann1 ,madler1 ,schmidt1 and other observers1 can well avoid the conclusion that the anomalies brought to light therein point strongly to the probability of the existence of some agency which occasionally modifies their appearance or entirely conceals them from view4 ,the following is one illustration out of many which might be quoted4 ,at a point in its course1 nearly due north of the ring-plain ,agrippa1 the great ,ariadaeus cleft sends out a branch which runs into the well-known ,hyginus cleft1 reminding one1 as ,dr4 ,klein remarks1 of two rivers connected in the shortest way by a canal4 ,this uniting furrow was detected by ,gruithuisen1 who observed it several times4 ,on some occasions it appeared perfectly straight1 at others very irregular2 but1 what is very remarkable1 although two such accurate observers as ,lohrmann and ,madler frequently scrutinised the region1 neither of them saw a trace of this object2 and but for its rediscovery by ,schmidt in #ahfb1 its existence would certainly have been ignored by selenographers as a mere figment of ,gruithuisen's too lively imagination4 ,dr4 ,klein has frequently seen this rill with great distinctness1 and at other times sought for it in vain2 though on each occasion the conditions of illumination1 libration1 and definition were practically similar4 ,i have sometimes found this cleft an easy object with a #d inch achromatic4 ,again1 many rills described by ,madler as very delicate and difficult to trace1 may now be easily followed in common telescopes4 ,in short1 the more direct telescopic observations accumulate1 and the more the study of minute detail is extended1 the stronger becomes the conviction1 that in spite of the absence of an appreciable atmosphere1 there may be something resembling low-lying exhalations from some parts of the surface which from time to time are sufficiently dense to obscure1 or even obliterate1 the region beneath them4 ,if1 as seems most probable1 these gigantic cracks are due to contractions of the moon's surface1 it is not impossible1 in spite of the assertions of the text-books to the effect that our satellite is now a changeless world1 that emanations may proceed from these fissures1 even if1 under the monthly alternations of extreme temperatures1 surface changes do not now occasionally take place from this cause also4 ,should this be so1 the appearance of new rills and the extension and modification of those already existing may reasonably be looked for4 ,many instances might be adduced tending to confirm this supposition1 to one of which1 as coming under my notice1 ,i will briefly refer4 ,on the evening of ,november #aa1 #ahhc1 when examining the interior of the great ring-plain ,mersenius with a power of #cej on an #h #a_/b inch reflector2 in addition to the two closely parallel clefts discovered by ,schmidt1 running from the inner foot of the north-eastern rampart towards the centre1 ,i remarked another distinct cleft crossing the northern part of the floor from side to side4 ,shortly afterwards1 ,m4 ,gaudibert1 one of our most experienced selenographers1 who has discovered many hitherto unrecorded clefts1 having seen my drawing1 searched for this object1 and1 though the night was far from favourable1 had distinct though brief glimpses of it with the moderate magnifying power of #ajj4 ,mersenius is a formation about #dj miles in diameter1 with a prominently convex interior1 containing much detail which has received more than ordinary attention from observers4 ,it has1 moreover1 been specially mapped by ,schmidt and others1 yet no trace of this rill was noted1 though objects much more minute and difficult have not been overlooked4 ,does not an instance of this kind raise a well-grounded suspicion of recent change which it is difficult to explain away8 ,to see the lunar clefts to the best advantage1 they must be looked for when not very far removed from the terminator1 as when so situated the black shadow of one side1 contrasted with the usually brightly- illuminated opposite flank1 renders them more conspicuous than when they are viewed under a higher sun4 ,though1 as a rule1 invisible at full moon1 some of the coarser clefts--as1 for example1 a portion of the ,hyginus furrow1 and that north of ,birt--may be traced as delicate white lines under a nearly vertical light4 ,for properly observing these objects1 a power of not less than #cjj on telescopes of large aperture is needed2 and in studying their minute and delicate details1 we are perhaps more dependent on atmospheric conditions than in following up any other branch of observational astronomy4 ,few indeed are the nights1 in our climate at any rate1 when the rough1 irregular character of the steep interior of even the coarser examples of these immense chasms can be steadily seen4 ,we can only hope to obtain a more perfect insight into their actual structural peculiarities when they are scrutinised under more perfect climatic circumstances than they have been hitherto4 ,when observing the ,hyginus cleft1 ,dr4 ,klein noticed that at one place the declivities of the interior displayed decided differences of tint4 ,at many points the reflected sunlight was of a distinctly yellow hue1 while in other places it was white1 as if the cliffs were covered with snow4 ,he compares this portion of the rill to the ,rhine valley between ,bingen and ,coblentz1 but adds that the latter1 if viewed from the moon1 would probably not present so fresh an appearance1 and would1 of course1 be frequently obscured by clouds4 ,since the erection of the great ,lick telescope on ,mount ,hamilton1 our knowledge of the details of some of the lunar clefts has been greatly increased1 as in the case of the ,ariadaeus cleft1 and many others4 ,professor ,w4,h4 ,pickering1 also1 at ,arequipa1 has made at that ideal astronomical site many observations which1 when published1 will throw more light upon their peculiar characteristics4 ,a few years ago ,m4,e4,l4 ,trouvelot of ,meudon drew attention to a curious appearance which he noted in connection with certain rills when near the terminator1 viz41 extremely attenuated threads of light on their sites and their apparent prolongations4 ,he observed it in the ring-plain ,eudoxus1 crossing the southern side of the floor from wall to wall2 and also in connection with the prominent cleft running from the north side of ,burg to the west of ,alexander1 and in some other situations4 ,he terms these phenomena ,murs enigmatiques4 ,apparent prolongations of clefts in the form of rows of hillocks or small mounds are very common4 ,,faults4--,these sudden drops in the surface1 representing local dislocations1 are far from unusual3 the best examples being the straight wall1 or railroad1 west of ,birt2 that which strikes obliquely across ,plato2 another which traverses ,phocylides2 and a fourth that has manifestly modified the mountain arm north of ,cichus4 ,they differ from the terrestrial phenomena so designated in the fact that the surface indications of these are destroyed by denudation or masked by deposits of subsequent date4 ,in many cases on the moon1 though its course cannot be traced in its entirety by its shadow1 yet the existence of a fault may be inferred by the displacement and fracture of neighbouring objects4 ,,valleys4--,features thus designated1 differing greatly both in size and character1 are met with in almost every part of the surface1 except on the grey plains4 ,while the smallest examples1 from their delicacy1 tenuity1 and superficial resemblance to rills1 are termed rill-valleys1 the larger and more conspicuous assume the appearance of coarse chasms1 gorges1 or trough-like depressions4 ,between these two extremes1 are many objects of moderate dimensions--winding or straight ravines and defiles bounded by steep mountains1 and shallow dales flanked by low rounded heights4 ,the rill valleys are very numerous1 only differing in many instances from the true rills in size1 and are probably due to the same cause4 ,among the most noteworthy valleys of the largest class must1 of course1 be placed the great valley of the ,alps1 one of the most striking objects in the northern hemisphere1 which also includes the great valley south-east of ,ukert4 ,the ,rheita valley1 the very similar chasm west of ,reichenbach1 and the gorge west of ,herschel1 are also notable examples in the southern hemisphere4 ,the borders of some of the ,maria 7especially that of the ,mare ,crisium7 and of many of the depressed rimless formations1 furnish instances of winding valleys intersecting their borders3 the hilly regions likewise often abound in long branching defiles4 ,,bright ,,ray-,,systems4--,reference has already been made to the faint light streaks and markings often found on the floors of the ring-mountains and in other situations1 and to the brilliant nimbi surrounding some of the smaller craters2 but1 in addition to these1 many objects on the moon's visible surface are associated with a much more remarkable and conspicuous phenomenon--the bright rays which1 under a high sun1 are seen either to radiate from them as apparent centres to great distances1 or1 in the form of irregular light areas1 to environ them1 and to throw out wide-spreading lucid beams1 extending occasionally many hundreds of miles from their origin4 ,the more striking of these systems were recognised and drawn at a very early stage of telescopic observation1 as may be seen if we consult the quaint old charts of ,hevel1 ,riccioli1 ,fontana1 and other observers of the seventeenth century1 where they are always prominently1 though very inaccurately1 portrayed4 ,the principal ray-systems are those of ,tycho1 ,copernicus1 ,kepler1 ,anaxagoras1 ,aristarchus1 ,olbers1 ,byrgius ,a1 and ,zuchius2 while ,autolycus1 ,aristillus1 ,proclus1 ,timocharis1 ,furnerius ,a1 and ,menelaus are grouped as constituting minor systems4 ,many additional centres exist1 a list of which will be found in the appendix4 ,the rays emanating from ,tycho surpass in extent and interest any of the others4 ,hundreds of distinct light streaks originate round the grey margin of this magnificent object1 some of them extending over a greater part of the moon's visible superficies1 and radiating1 in the words of ,professor ,phillips1 like false meridians1 or like meridians true to an earlier pole of rotation4 ,no systematic attempt has yet been made to map them accurately as a whole on a large scale1 for their extreme intricacy and delicacy would render the task a very difficult one1 and1 moreover1 would demand a long course of observation with a powerful telescope in an ideal situation2 but ,professor ,w4,h4 ,pickering1 observing under these conditions at ,arequipa1 has recently devoted considerable attention both to the ,tycho and other rays1 with especially suggestive and important results1 which may be briefly summarised as follows3-- 7#a47 ,that the ,tycho streaks do not radiate from the apparent centre of this formation1 but point towards a multitude of minute craterlets on its south-eastern or northern rims4 ,similar craterlets occur on the rims of other great craters1 forming ray-centres4 7#b47 ,speaking generally1 a very minute and brilliant crater is located at the end of the streak nearest the radiant point1 the streak spreading out and becoming fainter towards the other end4 ,the majority of the streaks appear to issue from one or more of these minute craters1 which rarely exceed a mile in diameter4 7#c47 ,the streaks which do not issue from minute craters1 usually lie upon or across ridges1 or in other similar exposed situations1 sometimes apparently coming through notches in the mountain walls4 7#d47 ,many of the ,copernicus streaks start from craterlets within the rim1 flow up the inside and down the outside of the walls4 ,kepler includes two such craterlets1 but here the flow seems to have been more uniform over the edges of the whole crater1 and is not distinctly divided up into separate streams4 7#e47 ,though there are similar craters within ,tycho1 the streaks from them do not extend far beyond the walls4 ,all the conspicuous ,tycho streaks originate outside the rim4 7#f47 ,the streaks of ,copernicus1 ,kepler1 and ,aristarchus are greyish in colour1 and much less white than those associated with ,tycho3 some white lines extending south-east from ,aristarchus do not apparently belong to the system4 ,in the case of craterlets lying between ,aristarchus and ,copernicus the streaks point away from the latter4 7#g47 ,there are no very long streaks2 they vary from ten to fifty miles in length1 and are rarely more than a quarter of a mile broad at the crater4 ,from this point they gradually widen out and become fainter4 ,their width1 however1 at the end farthest from the crater1 seldom exceeds five miles4 ,these statements1 especially those relating to the length of the streaks1 are utterly opposed to prevailing notions1 but ,professor ,pickering specifies the case of the two familiar parallel rays extending from the north-east of ,tycho to the region east of ,bullialdus4 ,his observations show that these streaks1 originating at a number of little craters situated from thirty to sixty miles beyond the confines of ,tycho1 enter a couple of broad slightly depressed valleys4 ,in these valleys are found numerous minute craters of the kind above described1 with intensely brilliant interiors4 ,when the streaks issuing from those craters near ,tycho are nearly exhausted1 they are reinforced by streaks from other craters which they encounter upon the way1 the streaks becoming more pronounced at these points4 ,these streaks are again reinforced farther out4 ,these parallel rays must therefore not be considered as two streaks1 but as two series of streaks1 the components of which are placed end to end4 ,thus1 according to ,professor ,pickering1 we must no longer regard the rays emanating from the ,tycho region and other centres as continuous1 but as consisting of a succession of short lengths1 diminishing in brilliancy but increasing in width1 till they reach the next crater lying in their direction1 when they are reinforced2 and the same process of gradual diminution in brightness and reinforcement goes on from one end to the other4 ,the following explanation is suggested to account for the origin of the rays3--,the earth and her satellite may differ not so much as regards volcanic action as in the densities of their atmospheres4 ,thus if the craterlets on the rim of ,tycho were constantly giving out large quantities of gas or steam1 which in other regions was being constantly absorbed or condensed1 we should have a wind uniformly blowing away from that summit in all directions4 ,should other summits in its vicinity occasionally give out gases1 mixed with any fine white powder1 such as pumice1 this powder would be carried away from ,tycho1 forming streaks4 ,the difficulty surrounding this very ingenious hypothesis is1 that though1 assuming the existence of pumice-emitting craters and regions of condensation1 there might be a more or less lineal and streaky deposition of this white material over large areas of the moon1 why should this deposit be so definitely arranged1 and why should these active little craters happen to lie on these particular lines8 ,the confused network of streaks round ,copernicus seem to respond more happily to the requirements of ,professor ,pickering's hypothesis1 for here there is an absence of that definiteness of direction so manifestly displayed in the case of the ,tycho rays1 and we can well imagine that with an area of condensation surrounding this magnificent object beyond the limits of the streaks1 and a number of active little craters on and about its rim1 the white material ejected might be drawn outwards in every direction by wind currents1 which possibly once existed1 and1 settling down1 assume forms such as we see4 ,nasmyth's well-known hypothesis attributes the radiating streaks to cracks in the lunar globe caused by the action of an upheaving force1 and accounts for their whiteness by the outwelling of lava from them which has spread to a greater or less distance on either side4 ,if the moon has been fractured in this way1 we can easily suppose that the craters formed on these fissures1 being in communication with the interior1 might eject some pulverulent white matter long after the rest of the surface with its other types of craters had attained a quiescent stage4 ,the ,tycho rays1 when viewed under ordinary conditions1 appear to extend in unbroken bands to immense distances4 ,one of the most remarkable1 strikes along the eastern side of ,fracastorius1 across the ,mare ,nectaris to ,guttemberg1 while another1 more central1 extends1 with local variations in brightness1 through ,menelaus1 over the ,mare ,serenitatis nearly to the north-west limb4 ,this is the ray that figures so prominently in rude woodcuts of the moon1 in which the ,mare ,serenitatis traversed by it is made to resemble the ,greek letter ,,phi4 ,the ,kepler1 ,aristarchus1 and ,copernicus systems1 though of much smaller extent1 are very noteworthy from the crossing and apparent interference of the rays2 while those near ,byrgius1 round ,aristarchus1 and the rays from ,proclus1 are equally remarkable4 ,nichol found that the rays from ,kepler cut through rays from ,copernicus and ,aristarchus1 while rays from the latter cut through rays from the former4 ,he therefore inferred that their relative ages stand in the order1--,copernicus1 ,aristarchus1 ,kepler4 ,as no branch of selenography has been more neglected than the observation of these interesting but enigmatical features1 one may hope that1 in spite of the exacting conditions as to situation and instrumental requirements necessary for their successful scrutiny1 the fairly equipped amateur in this less favoured country will not be deterred from attempting to clear up some of the doubts and difficulties which at present exist as to their actual nature4 ,,the ,,moon',s ,,albedo1 ,,surface ,,brightness1 c4--,sir ,john ,herschel maintained that the actual illumination of the lunar surface is not much superior to that of weathered sandstone rock in full sunshine4 ,i have1 he says1 frequently compared the moon setting behind the grey perpendicular facade of the ,table ,mountain1 illuminated by the sun just risen in the opposite quarter of the horizon1 when it has been scarcely distinguishable in brightness from the rock in contact with it4 ,the sun and moon being at nearly equal altitudes1 and the atmosphere perfectly free from cloud or vapour1 its effect is alike on both luminaries4 ,zollner's elaborate researches on this question are closely in accord with the above observational result4 ,though he considers that the brightest parts of the surface are as white as the whitest objects with which we are acquainted1 yet1 taking the reflected light as a whole1 he finds that the moon is more nearly black than white4 ,the most brilliant object on the surface is the central peak of the ring-plain ,aristarchus1 the darkest the floor of ,grimaldi1 or perhaps a portion of that of the neighbouring ,riccioli4 ,between these extremes1 there is every gradation of tone4 ,proctor1 discussing this question on the basis of ,zollner's experiments respecting the light reflected by various substances1 concludes that the dark area just mentioned must be notably darker than the dark grey syenite which figures in his tables1 while the floor of ,aristarchus is as white as newly fallen snow4 ,the estimation of lunar tints in the usual way1 by eye observations at the telescope1 involving as it does physiological errors which cannot be eliminated1 is a method far too crude and ambiguous to form the basis of a scientific scale or for the detection of slight variations4 ,an instrument on the principle of ,dawes' solar eyepiece has been suggested2 this1 if used with an invariable and absolute scale of tints1 would remove many difficulties attending these investigations4 ,the scale which was adopted by ,schroter1 and which has been used by selenographers up to the present time1 is as follows3-- #j deg4 ,black4 #a deg4 ,greyish black4 #b deg4 ,dark grey4 #c deg4 ,medium grey4 #d deg4 ,yellowish grey4 #e deg4 ,pure light grey4 #f deg4 ,light whitish grey4 #g deg4 ,greyish white4 #h deg4 ,pure white4 #i deg4 ,glittering white4 #aj deg4 ,dazzling white4 ,the following is a list of lunar objects published in the ,selenographical ,journal1 classed in accordance with this scale3-- #j deg4 ,black shadows4 #a deg4 ,darkest portions of the floors of ,grimaldi and ,riccioli4 #a #a_/b deg4 ,interiors of ,boscovich1 ,billy1 and ,zupus4 #b deg4 ,floors of ,endymion1 ,le ,monnier1 ,julius ,caesar1 ,cruger1 and ,fourier a4 #b #a_/b deg4 ,interiors of ,azout1 ,vitruvius1 ,pitatus1 ,hippalus1 and ,marius4 #c deg4 ,interiors of ,taruntius1 ,plinius1 ,theophilus1 ,parrot1 ,flamsteed1 and ,mercator4 #c #a_/b deg4 ,interiors of ,hansen1 ,archimedes1 and ,mersenius4 #d deg4 ,interiors of ,manilius1 ,ptolemaeus1 and ,guerike4 #d #a_/b deg4 ,surface round ,aristillus1 ,sinus ,medii4 #e deg4 ,walls of ,arago1 ,landsberg1 and ,bullialdus4 ,surface round ,kepler and ,archimedes4 #e #a_/b deg4 ,walls of ,picard and ,timocharis4 ,rays from ,copernicus4 #f deg4 ,walls of ,macrobius1 ,kant1 ,bessel1 ,mosting1 and ,flamsteed4 #f #a_/b deg4 ,walls of ,langrenus1 ,theaetetus1 and ,lahire4 #g deg4 ,theon1 ,ariadaeus1 ,bode ,b1 ,wichmann1 and ,kepler4 #g #a_/b deg4 ,ukert1 ,hortensius1 ,euclides4 #h deg4 ,walls of ,godin1 ,bode1 and ,copernicus4 #h #a_/b deg4 ,walls of ,proclus1 ,bode ,a1 and ,hipparchus c4 #i deg4 ,censorinus1 ,dionysius1 ,mosting ,a1 and ,mersenius ,b and c4 #i #a_/b deg4 ,interior of ,aristarchus1 ,la ,peyrouse ,,delta4 #aj deg4 ,central peak of ,aristarchus4 ,,temperature ,,of ,,the ,,moon',s ,,surface4--,till the subject was undertaken some years ago by ,lord ,rosse1 no approach was made to a satisfactory determination of the surface temperature of the moon4 ,from his experiments he inferred that the maximum temperature attained1 at or near the equator1 about three days after full moon1 does not exceed #bjj deg4 ,c41 while the minimum is not much under zero ,c4 ,subsequent experiments1 however1 both by himself and ,professor ,langley1 render these results more than doubtful1 without it is admitted that the moon has an atmospheric covering4 ,langley's results make it probable that the temperature never rises above the freezing-point of water1 and that at the end of the prolonged lunar night of fourteen days it must sink to at least #bjj deg4 below zero4 ,mr4 ,f4,w4 ,verey of the ,alleghany ,observatory has recently conducted1 by means of the bolometer1 similar researches as to the distribution of the moon's heat and its variation with the phase1 by which he has deduced the varying radiation from the surface in different localities of the moon under various solar altitudes4 ,,lunar ,,observation4--,in observing the moon1 we enjoy an advantage of which we cannot boast when most other planetary bodies are scrutinised2 for we see the actual surface of another world undimmed by palpable clouds or exhalations1 except such as exist in the air above us2 and can gaze on the marvellous variety of objects it presents much as we contemplate a relief map of our own globe4 ,but inasmuch as the manifold details of the relief map require to be placed in a certain light to be seen to the best advantage1 so the ring-mountains1 rugged highlands1 and wide-extending plains of our satellite1 as they pass in review under the sun1 must be observed when suitable conditions of illumination prevail1 if we wish to appreciate their true character and significance4 ,as a general rule1 lunar objects are best seen when they are at no great distance from the terminator1 or the line dividing the illumined from the unillumined portion of the spherical surface4 ,this line is constantly changing its position with the sun1 advancing slowly onwards towards the east at a rate which1 roughly speaking1 amounts to about #cj4e min4 in an hour1 or passing over #aj deg4 of lunar longitude in about #ai hrs4 #dj mins4 ,when an object is situated on this line1 the sun is either rising or setting on the neighbouring region1 and every inequality of the surface is rendered prominent by its shadow2 so that trifling variations in level and minor asperities assume for the time being an importance to which they have no claim4 ,if we are observing an object at lunar sunrise1 a very short time1 often only a few minutes1 elapses before the confusion caused by the presence of the shadows of these generally unimportant features ceases to interfere with the observation1 and we can distinguish between those details which are really noteworthy and others which are trivial and evanescent4 ,every formation we are studying should be observed1 and drawn if possible1 under many different conditions of illumination4 ,it ought1 in fact1 to be examined from the time when its loftiest heights are first illumined by the rising sun till they disappear at sunset4 ,this is1 of course1 practically impossible in the course of one lunation1 but by utilising available opportunities1 a number of observations may be obtained under various phases which will be more or less exhaustive4 ,it cannot be said that much is known about any object until an attempt has been made to carry out this plan4 ,features which assume a certain appearance at one phase frequently turn out to be altogether different when viewed under another2 important details obscured by shadows1 craters masked by those of neighbouring objects1 or by the shadows of their own rims1 are often only revealed when the sun has attained an altitude of ten degrees or more4 ,in short1 there is scarcely a formation on the moon which does not exemplify the necessity of noting its aspect from sunrise to sunset4 ,regard must also be had to libration1 which affects to a greater or less degree every object2 carrying out of the range of observation regions near the limb at one time1 and at another bringing into view others beyond the limits of the maps1 which represent the moon in the mean state of libration4 ,the area1 in fact1 thus brought into view1 or taken out of it1 is between #a_/abth and #a_/acth of the entire area of the moon1 or about the #a_/fth part of the hemisphere turned away from the earth4 ,it is convenient to bear in mind that we see an object under nearly the same conditions every #ei d4 #a h4 #bh m41 or still more accurately1 after the lapse of fifteen lunations1 or #ddb d4 #bc h4 ,many observers avoid the observation of objects under a high light4 ,this1 however1 should never be neglected when practicable1 though in some cases it is not easy to carry out1 owing to the difficulty in tracing details under these circumstances4 ,although to observe successfully the minuter features1 such as the rills and the smaller craterlets1 requires instruments of large aperture located in favourable situations1 yet work of permanent value may be accomplished with comparatively humble telescopic means4 ,a #d inch achromatic1 or a silver-on-glass reflector of #f or #f #a_/b inches aperture1 will reveal on a good night many details which have not yet been recorded1 and the possessor of instruments of this size will not be long in discovering that the moon1 despite of what is often said1 has not been so exhaustively surveyed that nothing remains for him to do4 ,only experience and actual trial will teach the observer to choose the particular eyepiece suitable for a given night or a given object4 ,it will be found that it is only on very rare occasions that he can accomplish much with powers which1 perhaps only on two or three nights in a year in this climate1 tell to great advantage2 though it sometimes happens that the employment of an eyepiece1 otherwise unsuitable for the night1 will1 during a short spell of good definition1 afford a fleeting glimpse of some difficult feature1 and thus solve a doubtful point4 ,it has often been said that the efficiency of a telescope depends to a great extent on the man at the eye end4 ,this is as true in the case of the moon as it is in other branches of observational astronomy4 ,observers1 especially beginners1 frequently fall into great error in failing to appreciate the true character of what they see4 ,in this way a shallow surface depression1 possibly only a few feet below the general level of the neighbouring country1 is often described as a vast gorge1 because1 under very oblique light1 it is filled with black shadow2 or an insignificant hillock is magnified into a mountain when similarly viewed4 ,hence the importance1 just insisted on1 of studying lunar features under as many conditions as possible before finally attempting to describe them4 ,however indifferent a draughtsman an observer may be1 if he endeavours to portray what he sees to the best of his ability1 he will ultimately attain sufficient skill to make his work useful for future reference3 in any case1 it will be of more value than a mere verbal description without a sketch4 ,doubt and uncertainty invariably attend to a greater or less extent written notes unaccompanied by drawings1 as some recent controversies1 respecting changes in ,linne and elsewhere1 testify4 ,now that photographs are generally available to form the basis of a more complete sketch1 much of the difficulty formerly attending the correct representation of the outline and grosser features of a formation has been removed1 and the observer can devote his time and attention to the insertion and description of less obvious objects4 ,,progress ,,of ,,selenography4--,till within recent years1 the systematic study of the lunar surface may be said to have been confined1 in this country at any rate1 to a very limited number of observers1 and1 except in rare instances1 those who possessed astronomical telescopes only directed them to the moon as a show object to excite the wonder of casual visitors4 ,the publication of ,webb's ,celestial ,objects in #ahei1 the supposed physical change in the crater ,linne1 announced in #ahff1 and the appearance of an unrecorded black spot near ,hyginus some ten years later1 had the effect of awakening a more lively interest in selenography1 and undoubtedly combined to bring about a change in this respect1 which ultimately resulted in the number of amateurs devoting much of their time to this branch of observational astronomy being notably increased4 ,still1 large telescopes1 as a rule1 held aloof for some unexplained reason1 or were only employed in a desultory and spasmodic fashion1 without any very definite object4 ,when the ,council of the ,british ,association for the ,advancement of ,science1 stimulated by the ,linne controversy1 deemed the moon to be worthy of passing attention1 observations1 directed to objects suspected of change 7the phenomena on the floor of ,plato7 were left to three or four observers1 under the able direction of ,mr4 ,birt1 the largest instruments available being an #h #a_/d inch reflector and the ,crossley refractor of #i inches aperture6 ,during the last decade1 however1 all this has been changed1 and we not only have societies1 such as the ,british ,astronomical ,association1 setting apart a distinct section for the systematic investigation of lunar detail1 but some of the largest and most perfect instruments in the world1 among them the noble refractor on ,mount ,hamilton1 employed in photographing the moon or in scrutinising her manifold features by direct observation4 ,hence1 it may be said that selenography has taken a new and more promising departure1 which1 among other results1 must lead to a more accurate knowledge of lunar topography1 and settle possibly1 ere long1 the vexed question of change1 without any residuum of doubt4 ,lunar photography as exemplified by the marvellous and beautiful pictures produced at the ,lick ,observatory under the auspices of ,dr4 ,holden1 and the exquisite enlargements of them by ,dr4 ,weinek of ,prague2 at ,paris by the brothers ,henry2 and at ,brussels by ,m4 ,prinz2 point to the not far distant time when we shall possess complete photographic maps on a large scale of the whole visible disc under various phases of illumination1 which will be of inestimable value as topographical charts4 ,when this is accomplished1 the observer will have at his command faithful representations of any formation1 or of any given region he may require1 to utilise for the study of the smaller details by direct observation4 ,desultory and objectless drawings and notes have hitherto been more or less characteristic of the work done1 even by those who have given more than ordinary attention to the moon4 ,though these1 if duly recorded1 are valuable as illustrating the physical structure1 the estimated brightness under various phases1 and other peculiarities of lunar features1 they do not materially forward investigations relating to the discovery of present lunar activity or to the detection of actual change4 ,it is reiterated ad nauseam in many popular books that the moon is a changeless world1 and it is implied that1 having attained a state when no further manifestations of internal or external forces are possible1 it revolves round the earth in the condition1 for the most part1 of a globular mass of vesicular lava or slag1 possessing no interest except as a notable example of a burnt-out planet4 ,in answer to these dogmatic assertions1 it may be said that1 notwithstanding the multiplication of monographs and photographs1 the knowledge we possess1 even of the larger and more prominent objects1 is far too slight to justify us in maintaining that changes1 which on earth we should use a strong adjective to describe1 have not taken place in connection with some of them in recent years4 ,would the most assiduous observer assert that his knowledge of any one of the great formations1 in the south-west quadrant1 for example1 is so complete that1 if a chasm as big as the ,val del ,bove was blown out from its flanks1 or formed by a landslip1 he would detect the change in the appearance of an area 7some three miles by four7 thus brought about1 unless he had previously made a very prolonged and exhaustive study of the object8 ,or1 again1 among formations of a different class1 the craters and crater-cones2 might not objects as large as ,monte ,nuovo or ,jorullo come into existence in many regions without any one being the wiser8 ,it would certainly have needed a persistent lunar astronomer1 and one furnished with a very perfect telescope1 to have noted the changes that have occurred within the old crater-ring of ,somma or among the ,santorin group during the past thirty years1 or even to have detected the effects resulting from the great catastrophe in ,a4,d4 #gi1 at ,vesuvius2 yet these objects are no larger than many which1 if they were situated on our satellite1 would be termed comparatively small1 if not insignificant4 ,one of the principal aims of lunar research is to learn as much as possible as to the present condition of the surface4 ,every one qualified to give an opinion will admit that this cannot be accomplished by roaming at large over the whole visible superficies1 but only by confining attention to selected areas of limited extent1 and recording and describing every object visible thereon1 under various conditions of illumination1 with the greatest accuracy attainable4 ,this plan was suggested and inaugurated nearly thirty years ago by ,mr4 ,birt1 under the patronage of the ,british ,association2 but as he proposed to deal with the entire disc in this way1 the magnitude and ambitious character of the scheme soon damped the ardour of those who at first supported it1 and it was ultimately abandoned4 ,it was1 however1 based on the only feasible principle which1 as it seems to the writer1 will not result in doubt and confusion4 ,now that photography has come to the assistance of the observer1 ,mr4 ,birt's proposal1 if confined within narrower limits1 would be far less arduous an undertaking than before1 and might be easily carried out4 ,a complete photographic survey of a few selected regions1 as a basis for an equally thorough and exhaustive scrutiny by direct observation1 would1 it is believed1 lead to a much more satisfactory and hopeful method for ultimately furnishing irrefragable testimony as to permanency or change than any that has yet been undertaken4 ,,catalogue ,,of ,,lunar ,,formations ,,first ,,quadrant ,,west ,,longitude #ij deg4 ,,to #fj deg4 ,,schubert4--,this ring-plain1 about #df miles in diameter1 situated on the ,n4,e4 side of the ,mare ,smythii1 is too near the limb to be well observed4 ,,neper4--,though still nearer the limb1 this walled-plain1 #gd miles in diameter1 is a much more conspicuous object4 ,it has a lofty border and a prominent central mountain1 the highest portion of a range of hills which traverses the interior from ,n4 to ,s4 ,,apollonius4--,a ring-plain1 #cj miles in diameter1 standing in the mountainous region ,s4 of the ,mare ,crisium4 ,there is a large crater on the ,s4,w4 wall1 and another1 somewhat smaller1 adjoining it on the ,n4 ,there are many brilliant craters in the vicinity4 ,,firmicus4--,a somewhat larger1 more regular1 but1 in other respects1 very similar ring-plain1 ,n4,w4 of the last4 ,some distance on the ,w41 ,madler noted a number of dark-grey streaks which apparently undergo periodical changes1 suggestive of something akin to vegetation4 ,they are situated near a prominent mountain situated in a level region4 ,,azout4--,a small ring-plain1 connected with the last by a lofty ridge4 ,it is the apparent centre of many other ridges and valleys which radiate from it towards the ,n4,w4 and the ,mare ,crisium4 ,there is a central mountain1 not an easy telescopic object1 on its dusky floor4 ,,condorcet4--,a very prominent ring-plain1 #de miles in diameter1 situated on the mountainous ,s4,w4 margin of the ,mare ,crisium4 ,it is encircled by a lofty wall about #hjjj feet in height4 ,the dark interior of this and of the three preceding formations render them easily traceable under a high angle of illumination4 ,,hansen4--,a ring-plain1 #cb miles in diameter1 on the ,w4 border of the ,mare ,crisium ,n4 of ,condorcet4 ,schmidt shows a central mountain and a terraced wall4 ,,alhazen4--,this ring-plain1 rather smaller than the last1 is the most northerly of the linear chain of formations1 associated with the highlands bordering the ,s4,w4 and the ,w4 flanks of the ,mare ,crisium4 ,it has a central mountain and other minor elevations on the floor4 ,there is a little ring between ,alhazen and ,hansen1 never very conspicuous in the telescope1 which is plainly traceable in good photographs4 ,,eimmart4--,a conspicuous ring-plain with bright walls on the ,n4,w4 margin of the ,mare ,crisium4 ,the ,e4 border attains a height of #aj1jjj feet above the interior1 which1 according to ,schmidt1 has a small central mountain4 ,there is a rill-like valley on the ,e4 of the formation4 ,,oriani4--,an irregular object1 #cb miles in diameter1 somewhat difficult to identify1 ,n4,w4 of the last4 ,there is a conspicuous crater on the ,n4 of it1 with which it is connected by a prominent ridge4 ,,plutarch4--,a fine ring-plain ,w4 of ,oriani1 with regular walls1 and1 according to ,neison1 with two central mountains1 only one of which ,i have seen4 ,both this formation and the last are beautifully shown in a photograph taken ,august #ai1 #ahia1 at the ,lick ,observatory1 when the moon's age was #ae d4 #aj hrs4 ,,seneca4--,rather smaller than ,plutarch4 ,too near the limb for satisfactory observation4 ,schmidt shows two considerable mountains in the interior4 ,the position of this object in ,schmidt's chart is not accordant with its place in ,beer and ,madler's map1 nor in that of ,neison4 ,,hahn4--,a ring-plain1 #df miles in diameter1 with a fine central mountain and lofty peaks on the border1 which is not continuous on the ,s4 ,there is a large and prominent crater on the ,e4 ,,berosus4--,a somewhat smaller object of a similar type1 ,n4 of ,hahn1 but with a loftier wall4 ,there is a want of continuity also in the border1 the eastern and western sections of which1 instead of joining1 extend for some distance towards the ,s41 forming a narrow gorge or valley4 ,outside the ,s4,e4 wall there is a small crater1 and some irregular depressions on the ,e4 ,the minute central mountain is only seen with difficulty under a low evening sun4 ,the bright region between ,hahn and ,berosus and the western flank of ,cleomedes is an extensive plain1 devoid of prominent detail1 and which1 according to ,neison1 includes an area of #dj1jjj square miles4 ,,gauss4--,a large1 and nearly circular walled-plain1 #aaa miles in diameter1 situated close to the ,n4,w4 limb1 and consequently always foreshortened into a more or less elongated ellipse4 ,but for this it would be one of the grandest objects in the first quadrant4 ,under the designation of ,mercurius ,falsus it received great attention from ,schroter1 who gives several representations of it in his ,selenotopographische ,fragmente1 which1 though drawn in his usual conventional style1 convey a juster idea of its salient features than many subsequent drawings made under far better optical conditions4 ,the border1 especially on the ,w41 is very complex1 and is discontinuous on the ,s41 where it is intersected by more than one pass1 and is prolonged far beyond the apparent limits of the formation4 ,the most noteworthy feature is the magnificent mountain chain which traverses the floor from ,n4 to ,s4 ,it is interesting to watch the progress of sunset thereon1 and see peak after peak disappear1 till only the great central boss and a few minute glittering points of light1 representing the loftier portions of the chain1 remain to indicate its position4 ,madler expatiates on the sublime view which would be obtained by any one standing on the highest peak and observing the setting sun on one side of him and the nearly full earth on the other2 while beneath him would lie a vast plain1 shrouded in darkness1 surrounded by the brilliantly illuminated peaks on the lofty border1 gradually passing out of sunlight4 ,in addition to the central mountain range1 there are some large rings1 craters1 hillocks1 c41 on the floor2 and on the inner slope of the ,w4 border there is a very large circular enclosure resembling a ring-plain1 not recorded in the maps4 ,schmidt shows a row of large craters on the outer slope of the ,e4 border4 ,of these1 one is very conspicuous under a low evening sun1 by reason of its brilliant walls and interior4 ,in the region between ,gauss and ,berosus is a number of narrow steep ridges which follow the curvature of the ,e4 wall4 ,,struve4--,a small irregularly-shaped formation1 open towards the ,s41 forming one of the curious group of unsymmetrical enclosures associated with ,messala4 ,its dark floor and a small dusky area on the ,n4 indicate its position under a high sun4 ,,carrington4--,a small ring-plain1 belonging to the ,messala group1 adjoining ,schumacher on the ,n4,w4 ,,mercurius4--,this formation is #be miles in diameter4 ,a small crater stands on the ,s4,e4 section of the wall4 ,there is a longitudinal range in the interior1 and on the ,w4 and ,n4,w4 the remains of two large walled-plains1 the more westerly of which is a noteworthy object under suitable conditions4 ,a short distance ,s4 is a large1 irregular1 and very dark marking4 ,on the ,n41 lies an immense bright plain1 extending nearly to the border of ,endymion4 ,,west ,,longitude #fj deg4 ,,to #dj deg4 ,,taruntius4--,notwithstanding its comparatively low walls1 this ring-plain1 #dd miles in diameter1 is a very conspicuous object under a rising sun4 ,like ,vitello and a few other formations1 it has an inner ring on the floor1 concentric with the outer rampart1 which ,i have often seen nearly complete under evening illumination4 ,there is a small bright crater on the ,s4,e4 wall1 and a larger one on the crest of the ,n4,e4 wall1 with a much more minute depression on the ,w4 of it1 the intervening space exhibiting signs of disturbance4 ,the upper portion of the wall is very steep1 contrasting in this respect with the very gentle inclination of the glacis1 which on the ,s4 extends to a distance of at least #cj miles before it sinks to the level of the surrounding country1 the gradient probably being as slight as #a in #de4 ,two low dusky rings and a long narrow valley with brilliant flanks are prominent objects on the plain ,e4 of ,taruntius under a low evening sun4 ,,secchi4--,a partially enclosed little ring-plain ,s4 of ,taruntius1 with a prominent central mountain and bright walls4 ,there is a short cleft running in a ,n4,e4 direction from a point near the ,e4 wall4 ,schmidt represents it as a row of inosculating craters4 ,,picard4--,the largest of the craters on the surface of the ,mare ,crisium1 #ba miles in diameter4 ,the floor1 which includes a central mountain1 is depressed about #bjjj feet below the outer surface1 and is surrounded by walls rising some #cjjj feet above the ,mare4 ,a small but lofty ring-plain1 ,picard ,e1 on the ,e41 near the border of the ,mare1 is remarkable for its change of aspect under different angles of illumination4 ,a long curved ridge running ,s4 from this1 with a lower ridge on the west1 sometimes resemble a large enclosure with a central mountain4 ,still farther ,s41 there is another bright deep crater1 a1 with a large low ring adjoining it on the ,s41 abutting on the ,s4,e4 border of the ,mare4 ,schroter bestowed much attention on these and other formations on the ,mare ,crisium1 and attributed certain changes which he observed to a lunar atmosphere4 ,,peirce4--,this formation1 smaller than ,picard1 is also prominent1 its border being very bright4 ,there is a central peak1 which1 though not an easy object1 ,i once glimpsed with a #d inch ,cook achromatic1 and have seen it two or three times since with an #h #a_/b inch ,calver reflector4 ,a small crater1 detected by ,schmidt1 which ,i once saw very distinctly under evening illumination1 stands on the floor at the foot of the ,w4 wall4 ,peirce ,a1 a deeper formation1 lies a little ,n4 of ,peirce1 and has also1 according to ,neison1 a very slight central hill1 which is only just perceptible under the most favourable conditions4 ,schmidt appears to have overlooked it4 ,,proclus4--,one of the most brilliant objects on the moon's visible surface1 and hence extremely difficult to observe satisfactorily4 ,it is about #ah miles in diameter1 with very steep walls1 and1 according to ,schmidt1 has a small crater on its east border1 where ,madler shows a break4 ,it is questionable whether there is a central mountain4 ,it is the centre of a number of radiating light streaks which partly traverse the ,mare ,crisium1 and with those emanating from ,picard1 ,peirce1 and other objects thereon1 form a very complicated system4 ,,macrobius4--,this1 with a companion ring on the ,w41 is a very beautiful object under a low sun4 ,it is #db miles in diameter1 and is encircled by a bright1 regular1 but complex border1 some #ac1jjj feet in height above the floor4 ,its crest is broken on the ,e4 by a large brilliant crater1 and its continuity is interrupted on the ,n4 by a formation resembling a large double crater1 which is associated with a number of low rounded banks and ridges extending some distance towards the ,n4,w41 and breaking the continuity of the glacis4 ,the ,w4 wall is much terraced1 and on the ,n4,w4 includes a row of prominent depressions1 well seen when the interior is about half illuminated under a rising sun4 ,the central mountain is of the compound type1 but not at all prominent4 ,the companion ring1 ,macrobius ,c1 is terraced internally on the ,w41 and the continuity of its ,n4 border broken by two depressions4 ,there is a rill-valley between its ,n4,e4 side and ,macrobius4 ,,cleomedes4--,a large oblong enclosure1 #gh miles in diameter1 with massive walls1 varying in altitude from #hjjj to #aj1jjj feet above the interior4 ,the most noteworthy features in connection with the circumvallation are the prominent depressions on the ,w4 wall4 ,under a rising sun1 when about one-fourth of the floor is in shadow1 three of these can be easily distinguished1 each resembling in form the analemma figure4 ,there are two other curious depressions at the ,s4,w4 end of the formation4 ,on the dark steel-grey floor are two irregular dusky areas1 and a narrow but bright central mountain1 on which1 according to ,schmidt1 stand two little craters4 ,there are two ring-plains on the ,s4,w4 quarter1 and a group of three associated craters on the ,n4 side1 one of which 7,a7 ,schroter believed came into existence after he commenced to observe the formation1 a supposition that has been shown by ,birt and others to be very improbable4 ,,tralles4--,a large irregular crater1 one of the deepest on the visible surface of the moon1 situated on the ,n4,e4 wall of ,cleomedes4 ,there is a crater on its ,n4 wall1 and1 according to ,schmidt1 some ridges and three closely associated craters on the floor4 ,,burckhardt4--,this object1 situated on an apparent extension of the ,w4 wall of ,cleomedes1 is #ce miles in diameter1 with a lofty border1 rising on the ,e4 to an altitude of nearly #ac1jjj feet4 ,it has a prominent central mountain and some low ridges on the floor1 which1 together with two minute craters on the ,s4,w4 wall1 ,i have seen under a low angle of morning illumination4 ,it is flanked both on the ,e4 and ,w4 by deep irregular depressions1 which present the appearance of having once been complete formations4 ,,geminus4--,a fine regular ring-plain1 #ed miles in diameter1 nearly circular1 with bright walls1 rising on the ,e4 to a height of more than #ab1jjj feet1 and on the opposite side to nearly #af1jjj feet above the floor4 ,their crest is everywhere very steep1 and the inner slope is much terraced4 ,there is a small but conspicuous mountain in the interior2 ,n4 of which ,i have seen a long ridge1 where ,schmidt shows some hillocks4 ,two fine clefts are easily visible within the ring1 one running for some distance on the ,s4,e4 side of the floor1 mounting the inner slope of the ,s4,w4 border to the summit ridge 7where it is apparently interrupted71 and then striking across the plain in a ,s4,w4 direction4 ,here it is accompanied for a short distance by a somewhat coarser companion1 running parallel to it on the ,n4 ,the other cleft occupies a very similar position on the ,n4,w4 side of the floor at the inner foot of the wall4 ,on several occasions1 when observing this formation and the vicinity1 ,i have been struck by its peculiar colour under a low evening sun4 ,at this time the whole region appears to be of a warm light brown or sepia tone4 ,,bernouilli4--,a very deep ring-plain on the ,w4 side of ,geminus4 ,under evening illumination its lofty ,w4 wall1 which rises to a height of nearly #ac1jjj feet above the floor1 is conspicuously brilliant4 ,this formation exhibits a marked departure from the circular type1 being bounded by rectilineal sides4 ,the inner slope of the ,w4 wall is slightly terraced4 ,the border on the ,s4 is much lower than elsewhere1 as is evident when the formation is on the evening terminator4 ,on the ,n4 is the deep crater ,messala a4 ,,newcomb4--,the most prominent of a group of formations standing in the midst of the ,haemus ,mountains4 ,its crest is nearly #ab1jjj feet above the floor1 on which there are some hills4 ,,messala4--,this fine walled-plain1 nearly #gj miles in diameter1 is1 with its surroundings1 an especially interesting object when observed under a low angle of illumination4 ,its complex border1 though roughly circular1 displays many irregularities in outline1 due mainly to rows of depressions4 ,the best view of it is obtained when the ,w4 wall is on the evening terminator4 ,at this phase1 if libration is favourable1 the manifold details of its very uneven and apparently convex floor are best seen4 ,on the ,s4,w4 side is a group of large craters associated with a number of low hills1 of which ,schmidt shows five2 but ,i have seen many more1 together with several ridges between them and the ,e4 wall4 ,i noted also a cleft1 or it may be a narrow valley1 running from the foot of the ,n4,w4 wall towards the centre4 ,on the floor1 abutting on the ,n4,e4 border1 is a semicircular ridge of considerable height1 and beyond the border on the ,n4,e4 there is another curved ridge1 completing the circle1 the wall forming the diameter4 ,this formation is clearly of more ancient date than ,messala1 as the ,n4,e4 wall of the latter has cut through it4 ,where ,messala joins ,schumacher there is a break in the border1 occupied by three deep depressions4 ,,schumacher4--,a large irregular ring-plain1 #bh miles in diameter1 associated with the ,n4 wall of ,messala1 and having other smaller rings adjoining it on the ,e4 and ,n4 ,the interior seems to be devoid of detail4 ,,hooke4--,another irregular ring-plain1 #bh miles in diameter1 on the ,n4,e4 of ,messala4 ,there is a bright crater of considerable size on the ,s4,w41 which is said to be more than #fjjj feet in depth1 and1 according to ,neison1 is visible as a white spot at full4 ,there is a smaller crater on the slope of the ,n4,w4 wall4 ,,shuckburgh4--,a square-shaped enclosure on the ,n4 of the last1 with a comparatively low border4 ,it has a conspicuous crater at its ,n4,w4 corner4 ,,berzelius4--,a considerable ring-plain of regular form1 with low walls and dark interior1 on which there is a central peak1 difficult to detect4 ,,franklin4--,a ring-plain1 #cc miles in diameter1 which displays a considerable departure from the circular type1 as the border is in great part made up of rectilineal sections4 ,both the ,w4 and ,n4,e4 wall is much terraced1 and rises about #hjjj feet above the dark floor1 on the ,s4 part of which there is a long ridge4 ,there is a bright little isolated mountain on the plain ,e4 of the formation1 and a conspicuous craterlet on the ,n4,w4 ,an incomplete ring1 with a very attenuated border1 abuts on the ,s4 side of ,franklin4 ,,cepheus4--,a peculiarly shaped ring-plain1 #bg miles in diameter4 ,the ,e4 border is nearly rectilineal1 while on the ,w41 the wall forms a bold curve4 ,there is a very brilliant crater on the summit of this section1 and a central mountain on the floor4 ,the ,w4 wall is much terraced4 ,w4 of ,cepheus1 close to the brilliant crater1 there is a cleft or narrow valley running ,n4 towards ,oersted4 ,,oersted4--,an oblong formation with very low walls1 scarcely traceable on the ,s4,e41 except when near the terminator4 ,there is a conspicuous crater on the ,n4,w4 side of the floor1 and a curious square enclosure1 with a crater on its ,w4 border1 abutting on the ,n4,e4 wall4 ,,chevallier4--,an inconspicuous object enclosed by slightly curved ridges4 ,it includes a deep bright crater4 ,on the ,n4 is a low square formation and a long ridge running ,n4 from it4 ,just beyond the ,n4,e4 wall is the fine large crater1 ,atlas ,a1 with a much smaller but equally conspicuous crater beyond4 ,a has a central hill1 which1 in spite of the bright interior1 is not a difficult feature4 ,,atlas4--,this1 and its companion ,hercules on the ,e41 form under oblique illumination a very beautiful pair1 scarcely surpassed by any other similar objects on the first quadrant4 ,its lofty rampart1 #ee miles in diameter1 is surmounted by peaks1 which on the ,n4 tower to an altitude of nearly #aa1jjj feet4 ,it exhibits an approach to a polygonal outline1 the lineal character of the border being especially well marked on the ,n4 ,the detail on the somewhat dark interior will repay careful scrutiny with high powers4 ,there is a small but distinct central mountain1 south of which stands a number of smaller hills1 forming with the first a circular arrangement1 suggestive of the idea that they represent the relics of a large central crater4 ,several clefts may be seen on the floor under suitable illumination1 among them a forked cleft on the ,n4,e4 quarter1 and two others1 originating at a dusky pit of irregular form situated near the foot of the ,s4,e4 wall1 one of which runs ,w4 of the central hills1 and the other on the opposite side4 ,a ridge1 at times resembling a light marking1 extends from the central mountain to the ,n4 border4 ,during the years #ahgj and #ahga ,i bestowed some attention on the dusky pit1 and was led to suspect that both it and the surrounding area vary considerably in tone from time to time4 ,professor ,w4,h4 ,pickering1 observing the formation in #ahia with a #ac inch telescope under the favourable atmospheric conditions which prevail at ,arequipa1 ,peru1 confirmed this supposition1 and has discovered some very interesting and suggestive facts relating to these variations1 which1 it is hoped1 will soon be made public4 ,on the plain a short distance beyond the foot of the glacis of the ,s4,e4 wall1 ,i have frequently noted a second dusky spot1 from which proceeds1 towards the ,e41 a long rill-like marking4 ,on the ,n4 there is a large formation enclosed by rectilineal ridges4 ,the outer slopes of the rampart of ,atlas are very noteworthy under a low sun4 ,,hercules4--,the eastern companion of ,atlas1 a fine ring-plain1 about #df miles in diameter1 with a complex border1 rising some #aa1jjj feet above a depressed floor4 ,there are few formations of its class and size which display so much detail in the shape of terraces1 apparent landslips1 and variation in brightness4 ,in the interior1 ,s4,e4 of the centre1 is a very conspicuous crater1 which is visible as a bright spot when the formation itself is hardly traceable1 two large craterlets slightly ,n4 of the centre1 and several faint little spots on the east of them4 ,the latter1 detected some years ago by ,herr ,hackel of ,stuttgart1 are arranged in the form of a horse-shoe4 ,there are two small contiguous craters on the ,s4,e4 wall1 one of which1 a difficult object1 was recently detected by ,mr4 ,w4,h4 ,maw1 ,f4,r4,a4,s4 ,the well-known wedge-shaped protuberance on the ,s4 wall is due to a large irregular depression4 ,on the bright inner slope of the ,n4 wall are manifest indications of a landslip4 ,,endymion4--,a large walled-plain1 #gh miles in diameter1 enclosed by a lofty1 broad1 bright border1 surmounted in places by peaks which attain a height of more than #aj1jjj feet above the interior1 one on the ,w4 measuring more than #ae1jjj feet4 ,the walls are much terraced and exhibit two or three breaks4 ,the dark floor appears to be devoid of detail4 ,schmidt1 however1 draws two large irregular mounds ,e4 of the centre1 and shows four narrow light streaks crossing the interior nearly parallel to the longer axis of the formation4 ,,de ,,la ,,rue4--,notwithstanding its great extent1 this formation hardly deserves a distinctive name1 as from the lowness of its border it is scarcely traceable in its entirety except under very oblique light4 ,schmidt1 nevertheless1 draws it with very definite walls1 and shows several ridges and small rings in the interior4 ,among these objects1 a little ,e4 of the centre1 there is a prominent peak4 ,,strabo4--,a small walled-plain1 #cb miles in diameter1 connected with the ,n4 border of the last4 ,,thales4--,a bright formation1 also associated with the ,n4 side of ,de la ,rue1 adjoining ,strabo on the ,n4,e4 ,schmidt shows a minute hill in the interior4 ,there are several unnamed formations1 large and small1 between ,de la ,rue and the limb1 some of which are well worthy of examination4 ,,west ,,longitude #dj deg4 ,,to #bj deg4 ,,maskelyne4--,a regular ring-plain1 #ai miles in diameter1 standing almost isolated in the ,mare ,tranquilitatis4 ,the floor1 which includes a central mountain1 is depressed some #cjjj feet below the surrounding surface4 ,there are prominent terraces on the inner slope of the walls4 ,schmidt shows no craters upon them1 but ,madler draws a small one on the ,e41 the existence of which ,i can confirm4 ,,manners4--,a brilliant little ring-plain1 #aa miles in diameter1 on the ,s4,e4 side of the ,mare ,tranquilitatis4 ,there appears to be no detail whatever in connection with its wall4 ,it has a distinct central mountain4 ,about three diameters distant on the ,s4,w4 there is a bright crater1 omitted by ,madler and ,neison4 ,,arago4--,a much larger formation1 #ah miles in diameter1 ,n4 of the last1 with a small crater on its ,n4 border1 and exhibiting two or three spurs from the wall on the opposite side4 ,the inner slopes are terraced1 and there is a small central mountain4 ,there are two curious circular protuberances on the ,mare ,e4 of ,arago1 which are well seen when the ,w4 longitude of the morning terminator is about #ai deg41 and a long cleft1 passing about midway between them1 and extending from the foot of the ,e4 wall to a small crater on the edge of the ,mare near ,sosigenes4 ,another cleft1 also terminating at this crater1 runs towards ,arago and the more northerly of the protuberances4 ,,cauchy4--,a bright little crater1 not more than #g or #h miles in diameter1 on the ,w4 side of the ,mare ,tranquilitatis1 ,n4,e4 of ,taruntius4 ,it has a peak on its ,w4 rim considerably loftier than the rest of the wall1 which is visible as a brilliant spot at sunrise long before the rest of the rampart is illuminated4 ,on the ,s4 there are two bright longitudinal ridges ranging from ,n4,e4 to ,s4,w4 ,these stand in the position where ,neison draws two straight clefts4 ,the ,cauchy cleft1 however1 lies ,n4 of these1 and terminates1 as shown by ,schmidt1 among the mountains ,n4,e4 of ,taruntius4 ,i have seen it thus on many occasions1 and it is so represented in a drawing by ,m4,e4 ,stuvaert 7,dessins de la ,lune74 ,there is a number of minute craters and mounds standing on the ,s4 side of this cleft1 and many others in the vicinity4 ,,jansen4--,owing to its comparatively low border1 this is not a very conspicuous object4 ,it is chiefly remarkable for the curious arrangement of the mountains and ridges on the ,s4 and ,w4 of it4 ,there is a bright little crater on the ,s4 side of the floor1 and many noteworthy objects of the same class in the neighbourhood4 ,the mountain arm running ,s41 and ultimately bending ,e41 forms a large incomplete hook-shaped formation terminating at a ring-plain1 ,jansen ,b4 ,the ridges in the ,mare ,tranquilitatis between ,jansen ,b4 and the region ,e4 of ,maskelyne display under a low sun foldings and wrinklings of a very extraordinary kind4 ,,maclear4--,a conspicuous ring-plain about #af miles in diameter4 ,the dark floor includes1 according to ,madler1 a delicate central hill which ,schmidt does not show4 ,neison1 however1 saw a faint greyish mark1 and an undoubted peak has been subsequently recorded4 ,i have not succeeded in seeing any detail within the border1 which in shape resembles a triangle with curved sides4 ,,ross4--,a somewhat larger ring-plain of irregular form1 on the ,n4,w4 of the last4 ,there are gaps on the bright ,s4,w4 border and a crater on the ,s4,e4 wall4 ,the central mountain is an easy feature4 ,,plinius4--,this magnificent object reminds one at sunrise of a great fortress or redoubt erected to command the passage between the ,mare ,tranquilitatis and the ,mare ,serenitatis4 ,it is #cb miles in diameter1 and is encompassed by a very massive rampart1 rising at one peak on the ,e4 to more than #fjjj feet above the interior1 and displaying1 especially on the ,s4,e41 and ,n41 many spurs and buttresses4 ,the exterior slopes at sunrise1 and even when the sun is more than #aj deg4 above the horizon1 are seen to be traversed by wide and deep valleys4 ,the ,s4 glacis is especially broad1 extending to a distance of #aj or #ab miles before it runs down to the level of the plain4 ,the shape of the circumvallation1 when it is fully illuminated1 approximates very closely to that of an equilateral triangle with curved sides4 ,there are two bright little craters on the outer slope1 just below the summit ridge on the ,s4,e41 and another1 larger1 on the ,n4 wall1 in which it makes a prominent gap4 ,the interior is considerably brighter than the surface of the surrounding ,mare1 and1 a little ,s4 of the centre1 includes two crater-like objects with broken rims4 ,these assume different aspects under different conditions of illumination1 and it is only when the floor is lighted by a comparatively low morning sun1 that their true character is apparent4 ,on the ,n4,w4 quarter of the interior are two smaller distinct craters1 and a square arrangement of ridges4 ,on the ,n4,e4 there are some hillocks and minor elevations4 ,the ,plinius rills form an especially interesting system1 and under favourable conditions may be seen in their entirety with a good #d inch refractor1 about the time when the morning terminator passes through ,julius ,caesar4 ,they consist of three long fissures1 originating amid the ,haemus highlands1 on the ,s4 side of the ,mare ,serenitatis1 and diverging towards the ,w4 ,the most southerly commences ,s4,s4,e4 of the ,acherusian promontory 7a great headland1 #ejjj feet high1 at the ,w4 termination of the ,haemus range71 and1 following a somewhat undulating course1 runs up to the ,n4 side of ,dawes4 ,under a low evening sun1 ,i have remarked many inequalities in the width of that portion of it immediately ,n4 of ,plinius1 which appear to indicate that it is here made up of rows of inosculating craters4 ,the cleft north of this originates very near it1 passes a little ,s4 of the promontory1 and runs to the ,e4 edge of the plateau surrounding ,dawes4 ,the third and most northerly cleft begins at a point immediately ,n4 of the promontory1 cuts through the ,s4 end of the well-known ,serpentine ridge on the ,mare ,serenitatis1 and1 after following a course slightly concave to the ,n41 dies out on the ,n4 side of the plateau4 ,this cleft forms the line of demarcation between the dark tone of the ,mare ,serenitatis and the light hue of the ,mare ,tranquilitatis1 traceable under nearly every condition of illumination1 and prominent in all good photographs4 ,,dawes4--,a ring-plain #ad miles in diameter1 situated ,n4,w4 of ,plinius1 on a nearly circular light area4 ,its bright border rises to a height of #bjjj feet above the ,mare1 and includes a central mountain1 a white marking on the ,e41 and a ridge running from the mountain to the ,s4 wall4 ,there are two closely parallel clefts on the ,n4 side of the plateau running from ,e4 to ,w41 that nearer ,dawes being the longer1 and having a craterlet standing upon it about midway between its extremities4 ,at its ,w4 termination there is a crater-row running at right angles to it4 ,the light area appears to be bounded on the ,e4 by a low curved bank4 ,,vitruvius4--,a ring-plain #ai miles in diameter with bright but not very lofty walls1 situated among the mountains near the ,s4,w4 side of the ,mare ,serenitatis4 ,it is surrounded by a region remarkable for its great variability in brightness4 ,there is a large bright ring-plain on the ,w41 with a less conspicuous companion on the ,s4 of it4 ,,maraldi4--,a deep but rather inconspicuous formation1 bounded on the ,w4 by a polygonal border4 ,a small ring-plain with a central mountain is connected with the ,s4,w4 wall2 and1 running in a ,n4 direction from this1 is a short mountain arm which joins a large circular enclosure with a low broken border standing on the ,n4 side of the ,mare ,tranquilitatis4 ,,littrow4--,a peculiar ring-plain1 rather smaller than the last1 some distance ,n4 of ,vitruvius1 on the rocky ,w4 border of the ,mare ,serenitatis4 ,it is shaped like the letter ,d1 the straight side facing the ,w4 ,there is a distinct crater on the ,n4 wall4 ,on the ,n4,w4 it is flanked by three irregular ring-plains1 and on the ,s4,e4 by a fourth4 ,neison shows two small mountains on the floor1 but ,schmidt1 whose drawing is very true to nature1 has no detail whatever4 ,a fine cleft may be traced from near the foot of the ,e4 wall to ,mount ,argaeus1 passing ,s4 of a bright crater on the ,mare ,e4 of ,littrow4 ,it extends towards the ,plinius system1 and is probably connected with it4 ,,mount ,,argaeus4--,there are few objects on the moon's visible surface which afford a more striking and beautiful picture than this mountain and its surrounding heights with their shadows a few hours after sunrise4 ,it attains an altitude of more than #hjjj feet above the ,mare1 and at a certain phase resembles a bright spear-head or dagger4 ,there is a well- defined rimmed depression abutting on its southern point4 ,,romer4--,a prominent formation of irregular outline1 #bd miles in diameter1 situated in the midst of the ,taurus highlands4 ,it has a very large central mountain1 a crater on the ,n4 side of the floor1 and terraced inner slopes4 ,some distance on the ,n4 is another ring1 nearly as large1 with a crater on its ,s4 rim1 and between this and ,posidonius is another with a wide gap on the ,s4 and a crater on its ,n4 border4 ,one of the most remarkable crater-rills on the moon runs from the ,e4 side of ,romer through this latter ring1 and then northwards on to the plain ,w4 of ,posidonius4 ,under suitable conditions1 it can be seen as such in a #d inch achromatic4 ,it is easily traceable as a rill in a photograph of the ,n4 polar region of the moon taken by ,,mm4 ,henry at the ,paris ,observatory1 and recently published in ,knowledge4 ,,le ,,monnier4--,a great inflection or bay on the ,w4 border of the ,mare ,serenitatis ,s4 of ,posidonius4 ,like many other similar formations on the edges of the ,maria1 it appears at one time or other to have had a continuous rampart1 which on the side facing the sea has been destroyed4 ,in this1 as in most of the other cases1 relics of the ruin are traceable under oblique light4 ,a fine crescent-shaped mountain1 #cjjj feet high1 stands near the ,s4 side of the gap1 and probably represents a portion of a once lofty wall4 ,it will repay the observer to watch the progress of sunrise on the whole of the ,w4 coast-line of the ,mare up to ,mount ,argaeus4 ,,posidonius4--,this magnificent ring-plain is justly regarded as one of the finest telescopic objects in the first quadrant4 ,its narrow bright wall with its serrated shadow1 the conspicuous crater1 the clefts and ridges and other details on the floor1 together with the beautiful group of objects on the neighbouring plain1 and the great ,serpentine ridge on the ,e41 never fail to excite the interest of the observer4 ,the circumvallation1 which is far from being perfectly regular1 is about #fb miles in diameter1 and1 considering its size1 is not remarkable for its altitude1 as it nowhere exceeds #fjjj feet above the interior1 which is depressed about #bjjj feet below the surrounding plain4 ,its continuity1 especially on the ,e41 is interrupted by gaps4 ,on the ,n41 the wall is notably deformed4 ,it is broader and more regular on the ,w41 where it includes a large longitudinal depression1 and on the ,n4,w4 section stand two bright little ring-plains4 ,on the floor1 which shines with a glittering lustre1 are the well-marked remains of a second ring1 nearly concentric with the principal rampart1 and separated from it by an interval of nine or ten miles4 ,the most prominent object1 however1 is the bright crater a little ,e4 of the centre4 ,this is partially surrounded on the ,w4 by three or four small bright mountains1 through which runs in a meridional direction a rill-valley1 not easily traced as a whole1 except under a low sun4 ,there is another cleft on the ,n4,e4 side of the interior1 which is an apparent extension of part of the inner ring1 a transverse rill-valley on the ,n41 a fourth quasi rill on the ,n4,w41 and a fifth short cleft on the ,s4 part of the floor4 ,between the principal crater and the ,s4,e4 wall are two smaller craters1 which are easy objects4 ,beyond the border on the ,n41 in addition to ,daniell1 are four conspicuous craters and many ridges4 ,,chacornac4--,this object1 connected with ,posidonius on the ,s4,w41 is remarkable for the brilliancy of its border and the peculiarity of its shape1 which is very clearly that of an irregular pentagon with linear sides4 ,i always find the detail within very difficult to make out4 ,two or more low ridges1 traversing the floor from ,n4 to ,s41 and a small crater1 are1 however1 clearly visible under oblique illumination4 ,schmidt draws a crater-rill1 and ,neison two parallel rills on the floor1--the former extends in a southerly direction to the ,w4 side of ,le ,monnier4 ,,daniell4--,a bright little ring-plain ,n4 of ,posidonius4 ,it is connected with a smaller ring-plain on the ,n4,w4 wall of the latter by a low ridge4 ,,bond1 ,g4,p4--,a small bright ring-plain #ab miles in diameter1 ,w4 of ,posidonius4 ,neison shows a crater both on the ,n4 and ,s4 rim4 ,schmidt omits these4 ,,maury4--,a bright deep little ring-plain1 about #ab miles in diameter1 on the ,w4 border of the ,lacus ,somniorum4 ,it is the centre of four prominent hill ranges4 ,,grove4--,a bright deep ring-plain1 #ae miles in diameter1 in the ,lacus ,somniorum1 with a border rising #gjjj feet above a greatly depressed floor1 which includes a prominent mountain4 ,,mason4--,the more westerly of two remarkable ring-plains1 situated in the highlands on the ,s4 side of the ,lacus ,mortis4 ,it is #ad miles in diameter1 has a distinct crater on its ,s4 wall1 and1 according to ,schmidt1 a crater on the ,e4 side of the floor4 ,,plana4--,a formation #bc miles in diameter1 closely associated with the last4 ,neison states that the floor is convex and higher than the surrounding region4 ,it has a triangular-shaped central mountain1 a crater1 and at least three other depressions on the ,s4,w4 wall where it joins ,mason4 ,,burg4--,a noteworthy formation1 #bh miles in diameter1 on the ,mare1 ,n4 of ,plana4 ,the floor is concave1 and includes a very large bright mountain1 which occupies a great portion of it4 ,the interior slopes are prominently terraced1 and there are several spurs associated with the glacis on the ,s4 and ,n4,e4 ,a distinct cleft runs from the ,n4 side of the formation to the ,s4,e4 border of the ,lacus ,somniorum1 which is crossed by another winding cleft running from a crater ,e4 of ,plana towards the ,n4,e4 ,,baily4--,a small ring-plain1 ,n4 of ,burg1 flanked by mountains1 with a large bright crater on the ,w4 ,the group of mountains standing about midway between it and ,burg are very noteworthy4 ,,gartner4--,a very large walled-plain with a low incomplete border on the ,e41 but defined on the ,w4 by a lofty wall4 ,schmidt shows a curved crater- row on the ,w4 side of the floor4 ,,democritus4--,a deep regular ring-plain1 about #be miles in diameter1 with a bright central mountain and lofty terraced walls4 ,,arnold4--,a great enclosure1 bounded1 like so many other formations hereabouts1 by straight parallel walls4 ,there is a somewhat smaller walled-plain adjoining it on the ,w4 ,,moigno4--,a ring-plain with a dark floor1 adjoining the last on the ,n4,e4 ,there is a conspicuous little crater in the interior4 ,,euctemon4--,this object is so close to the limb that very little can be made of its details under the most favourable conditions4 ,according to ,neison1 there is a peak on the ,n4 wall #aa1jjj feet in height4 ,,meton4--,a peculiarly-shaped walled-plain of great size1 exhibiting considerable parallelism4 ,the floor is seen to be very rugged under oblique illumination4 ,,west ,,longitude #bj deg4 ,,to #j deg4 ,,sabine4--,the more westerly of a remarkable pair of ring-plains1 of which ,ritter is the other member1 situated on the ,e4 side of the ,mare ,tranquilitatis a little ,n4 of the lunar equator4 ,it is about #ah miles in diameter1 and has a low continuous border1 which includes a central mountain on a bright floor4 ,from a mountain arm extending from the ,s4 wall1 run in a westerly direction two nearly parallel clefts skirting the edge of the ,mare4 ,the more southerly of these terminates near a depression on a rocky headland projecting from the coast-line1 and the other stops a few miles short of this4 ,a third cleft1 commencing at a point ,n4,e4 of the headland1 runs in the same direction up to a small crater near the ,n4 end of another cape-like projection4 ,at #h h4 on ,april #i1 #ahhf1 when the morning terminator bisected ,sabine1 ,i traced it still farther in the same direction4 ,all these clefts exhibit considerable variations in width1 but become narrower as they proceed westwards4 ,,ritter4--,is very similar in every respect to the last4 ,a curved rill mentioned by ,neison is on the ,n4,e4 side of the floor and is concentric with the wall4 ,on the ,n4 side of this ring-plain are three conspicuous craters1 the two nearer being equal in size and the third much smaller4 ,,schmidt4--,a bright crater at the foot of the ,s4 slope of ,ritter4 ,,dionysius4--,this crater1 #ac miles in diameter1 is one of the brightest spots on the lunar surface4 ,it stands on the ,e4 border of the ,mare1 about #cj miles ,e4,n4,e4 of ,ritter4 ,a distinct crater-row runs round its outer border on the ,w41 and ultimately1 as a delicate cleft1 strikes across the ,mare to the ,e4 side of ,ritter4 ,both crater-row and cleft are easy objects in a #d inch achromatic under morning illumination4 ,,ariadaeus4--,a bright little crater of polygonal shape1 with another crater of about one-third the area adjoining it on the ,n4,w41 situated on the rocky ,e4 margin of the ,mare ,tranquilitatis1 ,n4,e4 of ,ritter4 ,a short cleft runs from it towards the latter1 but dies out about midway4 ,a second cleft begins near its termination1 and runs up to the ,n4,e4 wall of ,ritter4 ,e4 of this pair a third distinct cleft1 originating at a point on the coast-line about midway between ,ariadaeus and ,dionysius1 ends near the same place on the border4 ,there is a fourth cleft extending from the ,n4 side of a little bay ,n4 of ,ariadaeus across the ,mare to a point ,n4,w4 of the more northerly of the three craters ,n4 of ,ritter4 ,at a small crater on the ,s4 flank of the mountains bordering the little bay ,n4 of ,ariadaeus originates one of the longest and most noteworthy clefts on the moon's visible surface1 discovered more than a century ago by ,schroter of ,lilienthal4 ,it varies considerably in breadth and depth1 but throughout its course over the plain1 between ,ariadaeus and ,silberschlag1 it can be followed without difficulty in a very small telescope4 ,e4 of the latter formation1 towards ,hyginus 7with which rill-system it is connected71 it is generally more difficult4 ,a few miles ,e4 of ,ariadaeus it sends out a short branch1 running in a ,s4,w4 direction1 which can be traced as a fine white line under a moderately high sun4 ,it is interesting to follow the course of the principal cleft across the plain1 and to note its progress through the ridges and mountain groups it encounters4 ,in the great ,lick telescope it is seen to traverse some old crater-rings which have not been revealed in smaller instruments4 ,about midway between ,ariadaeus and ,silberschlag it exhibits a duplication for a short distance1 first detected by ,webb4 ,,de ,,morgan4--,a brilliant little crater1 #d miles in diameter1 on the plain ,s4 of the ,ariadaeus cleft4 ,,cayley4--,a very deep bright crater1 with a dark interior1 ,n4 of the last1 and more than double its diameter4 ,there is a second crater between this and the cleft4 ,,whewell4--,another bright little ring1 about #c miles in diameter1 some distance to the ,e4 of ,de ,morgan and ,cayley4 ,,sosigenes4--,a small circular ring-plain1 #ad miles in diameter1 with narrow walls1 a central mountain1 and a minute crater outside the wall on the ,e42 situated on the ,e4 side of the ,mare ,tranquilitatis1 ,w4 of ,julius ,caesar4 ,there is another crater1 about half its diameter1 on the ,s41 connected with it by a low mound4 ,this has a still smaller crater on the ,w4 of it4 ,,julius ,,caesar4--,a large incomplete formation of irregular shape4 ,the wall on the ,e4 is much terraced1 and forms a flat ,s curve4 ,the summit ridge is especially bright1 and has a conspicuous little crater upon it4 ,on the ,w4 is a number of narrow longitudinal valleys trending from ,n4 to ,s41 included by a wide valley which constitutes the boundary on this side4 ,the border on the ,s4 consists of a number of low rounded banks1 those immediately ,e4 of ,sosigenes being traversed by several shallow valleys1 which look as if they had been shaped by alluvial action4 ,there is a brilliant little hill at the end of one of these valleys1 a few miles ,e4 of ,sosigenes4 ,the floor of ,julius ,caesar is uneven in tone1 becoming gradually duskier from ,s4 to ,n41 the northern end ranking among the darkest areas on the lunar surface4 ,there are at least three large circular swellings in the interior4 ,a long low mound1 with two or three depressions upon it1 bounds the wide valley on the ,e4 side4 ,,godin4--,a square-shaped ring-plain1 #bh miles in diameter1 with rounded corners4 ,the bright rampart is everywhere lofty1 except on the ,s41 is much terraced1 and includes a central mountain4 ,on the ,s4 a curious trumpet-shaped valley1 extending some distance towards the ,s4,w41 and bounded by bright walls1 is a noteworthy feature at sunrise4 ,there are other longitudinal valleys with associated ridges on this side of the formation1 all running in the same direction4 ,there is a large bright crater outside the border on the ,n4,e41 and1 between it and the wall1 another1 smaller1 which is readily seen under a high sun4 ,,agrippa4--,a ring-plain #bh miles in diameter on the ,n4 of the last1 with a terraced border rising to a height of between #gjjj and #hjjj feet above the floor1 which contains a large bright central mountain and two craters on the ,s4 ,the shape of this formation deviates very considerably from circularity1 the ,n4 wall1 on which stands a small crater1 being almost lineal4 ,on the ,w41 at a distance of a few miles1 runs the prominent mountain range1 extending northwards nearly up to the ,e4 flank of ,julius ,caesar1 which bounds the ,e4 side of the great ,ariadaeus plain4 ,between this rocky barrier and ,agrippa is a very noteworthy enclosure containing much minute detail and a long straight ridge resembling a cleft4 ,a few miles ,n4 of ,agrippa stands a small crater2 at a point ,w4 of which the ,hyginus cleft originates4 ,,silberschlag4--,a very brilliant crater1 #h or #i miles in diameter1 connected with the great mountain range just referred to4 ,the ,ariadaeus cleft cuts through the range a few miles ,n4 of it4 ,this neighbourhood at sunrise presents a grand spectacle4 ,with high powers under good atmospheric conditions1 the plain ,e4 of the mountains is seen to be traversed by a number of shallow winding valleys1 trending towards ,agrippa1 and separated by low rounded hills which have all the appearance of having been moulded by the action of water4 ,,boscovich4--,this is not a very striking telescopic object under any phase1 on account of its broken1 irregular1 and generally ill-defined border4 ,it is1 however1 remarkable as being one of the darkest spots on the visible surface3 in this respect a fit companion to ,julius ,caesar1 its neighbour on the ,w4 ,schmidt shows some ridges within it4 ,,rhaeticus4--,a very interesting formation1 about #be miles in diameter1 situated near the lunar equator1 with a border intersected by many passes4 ,a deep rill-like valley winds round its eastern glacis1 commencing on the ,s4 at a small circular enclosure standing at the end of a spur from the wall2 and1 after crossing a ridge ,w4 of a bright little crater on the ,n4 of the formation1 apparently joins the most easterly cleft of the ,triesnecker system4 ,a cleft traverses the ,n4 side of the floor of ,rhaeticus1 and extends across the plain on the ,e4 as far as the ,n4 side of ,reaumur4 ,,triesnecker4--,apart from being the centre of one of the most remarkable rill-systems on the moon1 this ring-plain1 though only about #ad miles in diameter1 is an object especially worthy of examination under every phase4 ,at sunrise1 and for some time afterwards1 owing to the superior altitude of the ,n4,w4 section of the wall1 a considerable portion of the border on the ,n4 and ,n4,e4 is masked by its shadow1 which thus appears to destroy its continuity4 ,on more than one occasion1 friends1 to whom ,i have shown this object under these conditions1 have likened it to a breached volcanic cone1 a comparison which at a later stage is seen to be very inappropriate4 ,the rampart is terraced within1 and exhibits many spurs and buttresses without1 especially on the ,n4,w4 ,the central mountain is small and not conspicuous4 ,the rill-system is far too complicated to be intelligibly described in words4 ,it lies on the ,w4 side of the meridian passing through the formation1 and extends from the ,n4 side of ,rhaeticus to the mountain-land lying between ,ukert and ,hyginus on the ,n4 ,birt likened these rills to an inverted river system1 a comparison which will commend itself to most observers who have seen them on a good night1 for in many instances they appear to become wider and deeper as they approach higher ground4 ,published maps are all more or less defective in their representations of them1 especially as regards that portion of the system lying ,n4 of ,triesnecker4 ,,hyginus4--,a deep depression1 rather less than #d miles across1 with a low rim of varying altitude1 having a crater on its ,n4 edge4 ,this formation is remarkable for the great cleft which traverses it1 discovered by ,schroter in #aghh4 ,the coarser parts of this object are easily visible in small telescopes1 and may be glimpsed under suitable conditions with a #b inch achromatic4 ,commencing a little ,w4 of a small crater ,n4 of ,agrippa1 it crosses1 as a very delicate object1 a plain abounding in low ridges and shallow valleys1 and runs nearly parallel to the eastern extension of the ,ariadaeus rill4 ,as it approaches ,hyginus it becomes gradually coarser1 and exhibits many expansions and contractions1 the former in many cases evidently representing craters4 ,when the phase is favourable1 it can be followed across the floor of ,hyginus1 and ,i have frequently seen the banks with which it appears to be bounded 7at any rate within the formation71 standing out as fine bright parallel lines amid the shadow4 ,on reaching the ,e4 wall1 it turns somewhat more to the ,n41 becomes still coarser and more irregular in breadth1 and ultimately expands into a wide valley on the ,n4,e4 ,it is connected with the ,ariadaeus cleft by a branch which leaves the latter at an acute angle on the plain ,e4 of ,silberschlag1 and joins it about midway between its origin ,n4 of ,agrippa and ,hyginus4 ,it is also probably joined to the ,triesnecker system by one or more branches ,e4 of ,hyginus4 ,on ,may #bg1 #ahgg1 ,dr4 ,hermann ,klein of ,cologne discovered1 with a #e #a_/b inch ,plosel dialyte telescope1 a dark apparent depression without a rim in the ,mare ,vaporum1 a few miles ,n4,w4 of ,hyginus1 which1 from twelve years' acquaintance with the region1 he was certain had not been visible during that period4 ,on the announcement of this discovery in the ,wochenschrift fur ,astronomie in ,march of the following year1 the existence of the object described by ,dr4 ,klein was confirmed1 and it was sedulously scrutinised under various solar altitudes4 ,to most observers it appeared as an ill-defined object with a somewhat nebulous border1 standing on an irregularly-shaped dusky area1 with two or more small dark craters and many low ridges in its vicinity4 ,a little ,e4 of it stands a curious spiral mountain called the ,schneckenberg4 ,the question as to whether ,hyginus ,n4 7as the dusky spot is called7 is a new object or not1 cannot be definitely determined1 as1 in spite of a strong case in favour of it being so1 there remains a residuum of doubt and uncertainty that can never be entirely cleared away4 ,after weighing1 however1 all that can be said for and against1 the hypothesis of change seems to be the most probable4 ,,ukert4--,this bright crater1 #ad miles in diameter1 situated in the region ,n4,e4 of ,triesnecker1 is surrounded by a very complicated arrangement of mountains2 and on the ,n4 and ,w4 is flanked by other enclosures4 ,it has a distinct central mountain4 ,its most noteworthy feature is the great valley1 more than #hj miles long1 which extends from ,n4,e4 to ,s4,w4 on the ,e4 side of it4 ,this gorge is at least six miles in breadth1 of great depth1 and is only comparable in magnitude with the well-known valley which cuts through the ,alps1 ,w4 of ,plato4 ,a delicate cleft1 not very clearly traceable as a whole1 begins near its ,n4 end1 and terminates amid the ramifications of the ,apennines ,s4 of ,marco ,polo4 ,,taquet4--,a conspicuous little crater on the ,s4 border of the ,mare ,serenitatis at the foot of the ,haemus ,mountains4 ,a branch of the great ,serpentine ridge1 which traverses the ,w4 side of this plain and other lesser elevations1 runs towards it4 ,,menelaus4--,a conspicuously bright regular ring-plain1 about #bj miles in diameter1 situated on the ,s4 coast-line of the ,mare ,serenitatis1 and closely associated with the ,haemus range4 ,it has a brilliant central mountain1 but no visible detail on the walls4 ,on the edge of the ,mare1 ,s4,w4 of it1 there is a curious square formation4 ,the bright streak traversing the ,mare from ,n4 to ,s41 which is so prominently displayed in old maps of the moon1 passes through this formation4 ,,sulpicius ,,gallus4--,another brilliant object on the south edge of the ,mare ,serenitatis1 some distance ,e4 of the last4 ,it is a deep circular crater about #h miles in diameter1 rising to a considerable height above the surface4 ,its shadow under a low morning sun is prominently jagged4 ,on the ,e4 are two bright mounds1 and ,s4 of that which is nearer the border of the ,mare1 commences a cleft which1 following the curvature of the coast- line1 terminates at a point in ,w4 long4 #i deg4 ,this object varies considerably in width and depth4 ,another shorter and coarser cleft runs ,s4 of this across an irregularly shaped bay or inflexion in the border of the ,mare4 ,,manilius4--,this1 one of the most brilliant objects in the first quadrant1 is about #be miles in diameter1 with walls nearly #hjjj feet above the floor1 which includes a bright central mountain4 ,the inner slope of the border on the ,e4 is much terraced and contains some depressions4 ,there is a small isolated bright mountain #bjjj feet high on the ,mare ,vaporum1 some distance to the ,e4 ,,bessel4--,a bright circular crater1 #ad miles in diameter1 on the ,s4 half of the ,mare ,serenitatis1 and the largest object of its class thereon4 ,its floor is depressed some #bjjj feet below the surrounding surface1 while the walls1 rising nearly #afjj feet above the plain1 have peaks both on the ,n4 and ,s4 about #bjj feet higher4 ,the shadows of these features1 noted by ,schroter in #agig1 and by many subsequent observers1 are very noteworthy4 ,i have seen the shadow of a third peak about midway between the two4 ,one may faintly imagine the magnificent prospect of the coast- line of the ,mare with the ,haemus range1 which would be obtained were it possible to stand on the summit of one of these elevations4 ,it is doubtful whether ,bessel has a central mountain4 ,neither ,madler nor ,schmidt have seen one1 though ,webb noted a peak on two occasions4 ,i fail to see anything within the crater4 ,the bright streak crossing the ,mare from ,n4 to ,s4 passes through ,bessel4 ,,linne4--,a formation on the ,e4 side of the ,mare ,serenitatis1 described by ,lohrmann and ,madler as a deep crater1 but which in #ahff was found by ,schmidt to have lost all the appearance of one4 ,the announcement of this apparent change led to a critical examination of the object by most of the leading observers1 and to a controversy which1 if it had no other result1 tended to awaken an interest in selenography that has been maintained ever since4 ,according to ,madler1 the crater was more than #f miles in diameter in his time1 and very conspicuous under a low sun1 a description to which it certainly did not answer in #ahfg or at any subsequent epoch4 ,it is anything but an easy object to see well1 as there is a want of definiteness about it under the best conditions1 though the minute crater1 the low ridges1 and the nebulous whiteness described by ,schmidt and noted by ,webb and others1 are traceable at the proper phase4 ,as in the case of ,hyginus ,n1 there are still many sceptics as regards actual change1 despite the records of ,lohrmann and ,madler2 but the evidence in favour of it seems to preponderate4 ,,conon4--,a bright little crater1 #aa miles in diameter1 situated among the intricacies of the ,apennines1 ,s4 of ,mount ,bradley4 ,it has a central hill1 which is not a difficult object4 ,,aratus4--,one of the most brilliant objects on the visible surface of the moon1 a crater #g miles in diameter1 ,s4 of ,mount ,hadley1 surrounded by the lofty mountain arms and towering heights of the ,apennines4 ,a peak close by on the ,n4 is more than #aj1jjj feet1 and another farther removed towards the ,n4,w4 is over #ad1jjj feet in altitude4 ,,autolycus4--,a ring-plain #bc miles in diameter1 deviating considerably from circularity1 ,w4 of ,archimedes1 on the ,mare ,imbrium1 or rather on that part of it termed the ,palus ,putredinis4 ,its floor1 which contains an inconspicuous central mountain1 is depressed some #djjj feet below the surrounding country4 ,with a power of #aej on a #d #e_/h achromatic1 ,dr4 ,sheldon of ,macclesfield has seen two shallow crateriform depressions in the interior1 one nearly central1 and the other about midway between it and the ,n4 wall4 ,the wall is terraced within1 and has a crater just below its crest on the ,w41 which1 when the opposite border is on the morning terminator1 is seen as a distinct notch4 ,autolycus is the centre of a minor ray-system4 ,,aristillus4--,a larger and much more elaborate ring-plain1 #cd miles in diameter1 ,n4 of ,autolycus4 ,its complex wall1 with its terraces within1 and its buttresses1 radiating spurs1 and gullies without1 forms a grand telescopic object under a low sun on a good night4 ,it rises on the east #aa1jjj feet above the ,mare1 and is about #bjjj feet lower on the ,w41 while the interior is depressed some #cjjj feet4 ,its massive central mountain1 surmounted by many peaks1 occupies a considerable area on the floor1 and exhibits a digitated outline at the base4 ,on the ,s4 and ,w4 a number of deep valleys radiate from the foot of the border1 some of them extending nearly as far as ,autolycus4 ,shallower but more numerous and regular features of the same class radiate towards the ,n4,e4 from the foot of the opposite wall4 ,on the ,n4,w4 are several curved ridges1 all trending towards ,theaetetus4 ,on the ,s4,e4 the surface is trenched by a number of crossed gullies1 well seen when the ,e4 wall is on the morning terminator4 ,just beyond the ,n4 glacis is a large irregular dusky enclosure with a central mound1 and another smaller low ring adjoining it on the ,s4,e4 ,the visibility of these objects is very ephemeral1 as they disappear soon after sunrise4 ,aristillus is also the centre of a bright ray system4 ,,theaetetus4--,a conspicuous ring-plain1 about #af miles in diameter1 in the ,palus ,nebularum1 ,n4,w4 of ,aristillus4 ,it is remarkable for its great depth1 the floor sinking nearly #ejjj feet below the surface4 ,its walls1 #gjjj feet high on the ,w41 are devoid of detail4 ,the glacis on the ,s4,w4 has a gentle slope1 and extends for a great distance before it runs down to the level of the plain4 ,not far from the foot of the wall on the ,n4 is a row of seven or eight bright little hills1 near the eastern side of which originates a distinct cleft that crosses the ,palus in a ,n4,w4 direction1 and terminates among mountains between ,cassini and ,calippus4 ,i have seen this object easily with a #d inch achromatic4 ,,calippus4--,a bright ring-plain #ag miles in diameter1 situated in the midst of the intricate ,caucasus ,mountain range4 ,on the ,e4 is a brilliant peak rising more than #ac1jjj feet above the ,palus ,nebularum1 and nearer the border1 on the ,n4,e41 is a second1 more than #ejj feet higher1 with many others nearly as lofty in the vicinity4 ,calippus has not apparently a central peak or any other features on the floor4 ,,cassini4--,this remarkable ring-plain1 about #cf miles in diameter1 is very similar in character to ,posidonius4 ,it has a very narrow wall1 nowhere more than #djjj feet in height1 and falling on the ,e4 to #aejj feet4 ,though a prominent and beautiful object under a low sun1 its attenuated border and the tone of the floor1 which scarcely differs from that of the surrounding surface1 render it difficult to trace under a high angle of illumination1 and perhaps accounts for the fact that it escaped the notice of ,hevel and ,riccioli2 though it is certainly strange that a formation which is thrown into such strong relief at sunrise and sunset should have been overlooked1 while others hardly more prominent at these times have been drawn and described4 ,the outline of ,cassini is clearly polygonal1 being made up of several rectilineal sections4 ,the interior1 nearly at the same level as the outside country1 includes a large bright ring-plain1 ,a1 #i miles in diameter and #bfjj feet in depth1 which has a good-sized crater on the ,s4 edge of a great bank which extends from the ,s4,w4 side of this ring-plain to the wall4 ,on the ,e4 side of the floor1 close to the inner foot of the border1 is a bright deep crater about two- thirds of the diameter of ,a1 and between it and the latter ,brenner has seen three small hills4 ,the outer slope of ,cassini includes much detail4 ,on the ,s4,w4 is a row of shallow depressions just below the crest of the wall1 and near the foot of the slope is a large circular shallow depression associated with a valley which runs partly round it4 ,the shape of the glacis on the ,w4 is especially noteworthy1 the ,s4,w4 and ,n4,w4 sides meeting at a slightly acute angle at a point #aj or #ab miles ,w4 of the summit of the ring4 ,on the outer ,e4 slope is a curious elongated depression1 and on the ,n4 slope two large dusky rings1 well shown by ,schmidt1 but omitted in other maps4 ,most of these details are well within the scope of moderate apertures4 ,perhaps the most striking view of ,cassini and its surroundings is obtained when the morning terminator is on the central meridian4 ,,alexander4--,a large irregularly shaped plain1 at least #fj miles in longest diameter1 enclosed by the ,caucasus ,mountains4 ,on the ,s4,w4 and ,n4,w4 the border is lineal4 ,it has a dark level floor on which there is a great number of low hills4 ,,eudoxus4--,a bright deep ring-plain1 about #dj miles in diameter1 in the hilly region between the ,mare ,serenitatis and the ,mare ,frigoris1 with a border much broken by passes1 and deviating considerably from circularity4 ,its massive walls1 rising more than #aa1jjj feet above the floor on the ,w41 and about #aj1jjj feet on the opposite side1 are prominently terraced1 and include crater-rows in the intervening valleys1 while their outer slopes present a complicated system of spurs and buttresses4 ,there is a bright crater on the ,n4 glacis1 and some distance beyond the wall on the ,n4,w4 is a small ring-plain1 and on the ,s4,e4 another1 with a conspicuous crater between it and the wall4 ,neison draws attention to an area of about #adjj square miles on the ,n4,e4 which is covered with a great multitude of low hills4 ,e4 of ,eudoxus are two short crossed clefts1 and on the ,n4 a long cleft of considerable delicacy running from ,n4,e4 to ,s4,w4 ,it was in connection with this formation that ,trouvelot1 on ,february #bj1 #ahgg1 when the terminator passed through ,aristillus and ,alphonsus1 saw a very narrow thread of light crossing the ,s4 part of the interior and extending from border to border4 ,he noted also similar appearances elsewhere1 and termed them ,murs enigmatiques4 ,,aristoteles4--,a magnificent ring-plain1 #fj miles in diameter1 with a complex border1 surmounted by peaks1 rising to nearly #aa1jjj feet above the floor1 one of which on the ,w41 pertaining to a terrace1 stands out as a brilliant spot in the midst of shadow when the interior is filled with shadow4 ,the formation presents its most striking aspect at sunrise1 when the shadow of the ,w4 wall just covers the floor1 and the brilliant inner slope of the ,e4 wall with the little crater on its crest is fully illuminated4 ,at this phase the details of the terraces are seen to the best advantage4 ,the arrangement of the parallel ridges and rows of hills on the ,n4,e4 and ,s4,w4 is likewise better seen at this time than under an evening sun4 ,a bright and deep ring-plain1 about #aj miles in diameter1 with a distinct central mountain1 is connected with the ,w4 wall4 ,,egede4--,a lozenge-shaped formation1 about #ah miles from corner to corner1 bounded by walls scarcely more than #djj feet in height4 ,it is consequently only traceable under very oblique illumination4 ,,the ,,great ,,alpine ,,valley4--,a great wedge-shaped depression1 cutting through the ,alps ,w4 of ,plato1 from ,w4,n4,w4 to ,e4,s4,e4 ,it is more than #hj miles in length1 and varies in breadth from #f miles on the ,s4 to less than #d miles on the ,n41 where it approaches the ,s4 border of the ,mare ,frigoris4 ,for a greater part of its extent it is bounded on the ,s4,w4 side by a precipitous linear cliff1 which1 under a low evening sun1 is seen to be fringed by a row of bright little hills4 ,these are traceable up to one of the great mountain masses of the ,alps1 forming the ,s4,w4 side of the great oval-shaped expansion of the valley1 whose shape has been appropriately compared to that of a ,florence oil-flask1 and which ,webb terms a grand amphitheatre4 ,on the opposite or ,n4,e4 side1 the boundary of the valley is less regular1 following a more or less undulating line up to a point opposite1 and a little ,n4 of1 the great mountain mass1 where it abuts on a shallow quasi enclosure with lofty walls1 which1 projecting westwards1 considerably diminish the width of the valley4 ,south of this lies another curved mountain ring1 which still farther narrows it4 ,this curtailment in width represents the neck of the flask1 and is apparently about #af or #ag miles in length1 and from #c to #d miles in breadth1 forming a gorge1 bordered on the ,w4 by nearly vertical cliffs1 towering thousands of feet above the bottom of the valley2 and on the ,e4 by many peaked mountains of still greater altitude4 ,at the entrance to the amphitheatre1 the actual distance between the colossal rocks which flank the defile is certainly not much more than #b miles4 ,from this standpoint the view across the level interior of the elliptical plain would be of extraordinary magnificence4 ,towards the ,s41 but more than #ab miles distant1 the outlook of an observer would be limited by some of the loftiest peaks of the ,alps1 whose flanks form the boundary of the enclosure1 through which1 however1 by at least three narrow passes he might perchance get a glimpse of the ,mare ,imbrium beyond4 ,the broadest of these aligns with the axis of the valley4 ,it is hardly more than a mile wide at its commencement on the ,s4 border of the amphitheatre1 but expands rapidly into a trumpet-shaped gorge1 flanked on either side by the towering heights of the ,alps as it opens out on to the ,mare4 ,the bottom1 both of the amphitheatre and of the long wedge-shaped valley1 appears to be perfectly level1 and1 as regards the central portion of the latter1 without visible detail4 ,under morning illumination ,i have1 however1 frequently seen something resembling a ridge partially crossing the neck1 and1 near sunset1 a tongue of rock jutting out from the ,e4 flank of the constriction1 and extending nearly from side to side4 ,at the base of the cliff bordering the valley on the ,s4,w41 five or six little circular pits have been noted1 some of which appear to have rims4 ,they were seen very perfectly with powers of #cej and #djj on an #h #a_/b inch ,calver reflector at #h h4 on ,january #be1 #ahhe1 and have been observed1 but less perfectly1 on subsequent occasions4 ,the most northerly is about #aj miles from the ,n4,w4 end of the formation1 and the rest occur at nearly regular intervals between it and the neck4 ,in the neighbourhood of the valley1 on either side1 there are several bright craters4 ,three stand near the ,n4,e4 edge1 and one of considerable size near the ,n4,w4 end on the opposite side4 ,a winding cleft crosses the valley about midway1 which1 strange to say1 is not shown in the maps1 though it may be seen in a #d inch achromatic4 ,it originates apparently at a bright triangular mountain on the plain ,s4,w4 of the valley1 and1 after crossing the latter somewhat obliquely1 is lost amid the mountains on the opposite side4 ,that portion of it on the bottom of the valley is easily traceable under a high light as a white line4 ,the region ,n4 of the ,alps on the ,s4,w4 side of the valley presents many details worthy of examination4 ,among them1 parallel rows of little hills1 all extending from ,n4,w4 to ,s4,e4 ,there is also a number of still smaller objects of the same type on the ,e4 side4 ,the great ,alpine valley1 though first described by ,schroter1 is said to have been discovered on ,september #bb1 #agbg1 by ,bianchini1 but it is very unlikely that an object which is so prominent when near the terminator was not often remarked before this4 ,,archytas4--,a bright ring-plain1 #ba miles in diameter1 on the edge of the ,mare ,frigoris1 due ,n4 of the ,alpine ,valley1 with regular walls rising about #ejjj feet above the interior on the ,n4,w41 and about #djjj feet on the opposite side4 ,it has a very bright central mountain4 ,several spurs radiate from the wall on the ,s41 and a wide valley1 flanked by lofty heights1 forming the ,s4,w4 boundary of ,w4,c4 ,bond1 originates on the ,n side4 ,there is also a crater-rill running towards the ,n4,w4 ,on the ,mare1 ,s4,w4 of ,archytas1 is a somewhat smaller ring-plain1 ,archytas ,a 7called by ,schmidt1 ,,protagoras71 with lofty walls and a central hill4 ,,christian ,,mayer4--,a prominent rhomboidal-shaped ring-plain1 #ah miles in diameter1 associated on every side1 except the ,n41 with a number of irregular inconspicuous enclosures4 ,it has a central peak4 ,madler discovered two delicate short clefts1 both running from ,n4,w4 to ,s4,e41 one on the ,w4 and the other on the ,e4 of this formation4 ,w4,c4 ,,bond4--,a great enclosed plain of rhomboidal shape on the ,n4 of ,archytas1 the bright ring-plain ,timaeus standing near its ,e4 corner1 and another conspicuous but much smaller enclosure with a smaller crater ,w4 of it on the floor at the opposite angle4 ,the interior1 which is covered with rows of hillocks1 is very noteworthy at sunrise4 ,,barrow4--,there are few more striking or beautiful objects at sunrise than this1 mainly because of the peculiar shape of its brilliant border and the remarkable shadows of the lofty peaks on its western wall4 ,there is a notable narrow gap in the rampart on the ,w41 which appears to extend to the level of the floor4 ,the walls1 especially on the ,s41 are very irregular1 and include two large deep craters and some minor depressions4 ,if the formation is observed when its ,e4 wall is on the morning terminator1 a fine view is obtained of the remarkable crater-row which winds round the ,n4 side of ,goldschmidt4 ,barrow is about #dj miles in diameter4 ,according to ,schmidt1 there is one crater in the interior1 a little ,s4,e4 of the centre4 ,,scoresby4--,a much fore-shortened deep ring-plain1 #cf miles in diameter1 between ,barrow and the limb4 ,it has a central mountain with two peaks1 which are very difficult to detect4 ,,challis4--,a ring-plain adjoining ,scoresby on the ,n4,e4 ,it is of about the same size and shape4 ,,main4--,a very similar formation1 on the ,n4 of the last1 much too near the limb to be well observed4 ,,second ,,quadrant ,,east ,,longitude #j deg4 ,,to #bj deg4 ,,murchison4--,a considerable ring-plain about #ce miles across on the ,e41 where it abuts on ,pallas4 ,it is a pear-shaped formation1 bounded on the ,n4 by a mountainous region1 and gradually diminishes in width towards the ,s4,e41 on which side it is open to the plain4 ,the walls are of no great altitude1 but1 except on the ,n4,w41 are very bright4 ,at the ,s4 termination of the ,w4 wall there is an exceedingly brilliant crater1 ,murchison ,a1 five miles in diameter and some #cjjj feet deep2 adjoining which on the ,n4,w4 is an oval depression and a curious forked projection from the border4 ,the only objects visible in the interior are a few low ridges on the ,e4 side1 and a number of long spurs running out from the wall on the ,n4 towards the centre of the floor4 ,murchison ,a is named ,,chladni by ,lohrmann4 ,,pallas4--,a fine ring-plain1 about #cb miles in diameter1 forming with ,murchison an especially beautiful telescopic object under suitable illumination4 ,its brilliant border1 broken by gaps on the ,w41 where it abuts on ,murchison1 has a bright crater on the ,n4,e41 from which1 following the curvature of the wall1 and just below its crest1 runs a valley in an easterly direction4 ,there is a large bright central mountain on the floor1 with a smaller elevation to the ,s4 of it1 and a ridge extending from the ,n4 wall to near the centre4 ,on the ,w41 a section of the border is continued in a ,n4 direction far beyond the limits of the formation2 and on the ,s4 it is connected with a small incomplete ring2 on the ,e4 of which1 near the foot of the wall1 is a somewhat smaller and much duskier enclosure4 ,,bode4--,a brilliant ring-plain1 #i miles in diameter1 situated on the ,n4 side of ,pallas4 ,its walls rise about #ejjj feet above the interior1 which is considerably depressed1 and includes1 according to ,schmidt and ,webb1 a mountain or ridge4 ,there are two parallel valleys on the ,w41 which are well worth examination4 ,,sommering4--,an incomplete ring-plain1 #ag miles in diameter1 situated on the lunar equator4 ,it has rather low broken walls and a dark interior4 ,,schroter4--,a somewhat larger formation1 with a border wanting on the ,s4 ,schmidt draws a considerable crater on the ,s4,w4 side of the floor4 ,it was in the region north of this object1 which abounds in little hills and low ridges1 that in the year #ahbb ,gruithuisen discovered a very remarkable formation consisting of a number of parallel rows of hills branching out 7like the veins of a leaf from the midrib7 from a central valley at an angle of #de deg41 represented by a depression between two long ridges running from north to south4 ,the regularly arranged hollows between the hills and the longitudinal valley suggested to his fertile imagination that he had at last found a veritable city in the moon--possibly the metropolis of ,kepler's ,subvolvani1 who were supposed to dwell on that hemisphere of our satellite which faces the earth4 ,at any rate1 he was firmly convinced that it was the work of intelligent beings1 and not due to natural causes4 ,this curious arrangement of ridges and furrows1 which1 according to ,webb1 measures about #bc miles both in length and breadth1 is1 owing to the shallowness of the component hills and valleys1 a very difficult object to see in its entirety1 as it must be viewed when close to the terminator1 and even then the sun's azimuth and good definition do not always combine to afford a satisfactory glimpse of its ramifications4 ,m4 ,gaudibert has given a drawing of it in the ,english ,mechanic1 vol4 xviii4 p4 #fch4 ,,gambart4--,a regular ring-plain1 #af miles in diameter1 with a low border and without visible detail within2 situated nearly on the lunar equator1 about #acj miles ,s4,s4,w4 of ,copernicus1 at the ,n4,w4 edge of a very hilly region4 ,a prominent pear-shaped mountain1 with a small crater upon it1 stands a short distance on the ,s4,w41 and further in the same direction1 a large bright crater with two much smaller craters on the ,n4 of it4 ,the rough hilly district about midway between ,copernicus and ,gambart is remarkable for its peculiar dusky tone and for certain small dark spots1 first seen by ,schmidt1 and subsequently carefully observed by ,dr4 ,klein4 ,the noteworthy region where these peculiar features are found represents an area of many thousand square miles1 and must resemble a veritable ,malpais1 covered probably with an incalculable number of craters1 vents1 cones1 and pits1 filled with volcanic debris4 ,it is among details of this character that the true analogues of some terrestrial volcanoes must be looked for4 ,under a low angle of illumination the surface presents an extraordinarily rough aspect1 well worthy of examination1 but the dusky areas and the black spots can only be satisfactorily distinguished under a somewhat high sun4 ,i have1 however1 seen them fairly well when the ,w4 wall of ,reinhold was on the morning terminator4 ,,marco ,,polo4--,a small and very irregularly-shaped enclosure 7difficult to see satisfactorily7 on the ,s4 flank of the ,apennines4 ,it is hemmed in on every side by mountains4 ,,eratosthenes4--,a noble ring-plain1 #ch miles in diameter2 a worthy termination of the ,apennines4 ,the best view of it is obtained under morning illumination when the interior is about half-filled with shadow4 ,at this phase the many irregular terraces on the inner slope of the ,e4 wall 7which rises at one peak #af1jjj feet above an interior depressed #hjjj feet below the ,mare ,imbrium7 are seen to the best advantage4 ,the central mountain is made up of two principal peaks1 nearly central1 from which two bright curved hills extend nearly up to the ,n4,w4 wall1--the whole forming a ,v-shaped arrangement4 ,on the ,s4 there is a narrow break in the wall1 and the ,s4,w4 section of it seems to overlap and extend some distance beyond the ,s4,e4 section4 ,the border on the ,s4,w4 is remarkable for the great width of its glacis4 ,eratosthenes exhibits a marked departure from circularity1 especially on the ,e41 where the wall consists of two well-marked linear sections1 with an intermediate portion where the crest for #bj miles or more bends inwards or towards the centre4 ,from the ,s4,e4 flank of this formation extends towards the ,w4 side of ,stadius one of the grandest mountain arms on the moon's visible surface1 rising at one place #ijjj feet1 and in two others #ejjj and #cjjj feet respectively above the ,mare ,imbrium4 ,if this magnificent object is observed when the morning terminator falls a little ,e4 of ,stadius1 it affords a spectacle not easily forgotten4 ,i have often seen it at this phase when its broad mass of shadow extended across the well-known crater-row ,w4 of ,copernicus1 some of the component craters appearing between the spires of shade representing the loftiest peaks on the mountain arm4 ,there is a prominent little crater on the crest of the arm between two of the peaks1 and another on the plain to the west4 ,,stadius4--,an inconspicuous though a very interesting formation1 #dc miles in diameter1 ,w4 of ,copernicus1 with a border scarcely exceeding #bjj feet in height4 ,hence it is not surprising that it was for a long time altogether overlooked by ,madler4 ,except as a known object1 it is only traceable under very oblique illumination1 and even then some attention is required before its very attenuated wall can be followed all round4 ,it is most prominent on the ,w41 where it apparently consists of a ,s4 extension of the ,eratosthenes mountain-arm1 and is associated with a number of little craters and pits4 ,this is succeeded on the ,s4,w4 by a narrow strip of bright wall1 and on the ,s4 by a section made up of a piece of straight wall and a strip curving inwards1 forming the ,s4 side4 ,on the ,e4 the border assumes a very ghostly character1 and appears to be mainly defined by rows of small depressions and mounds4 ,on the ,n4,e41 ,n41 and ,n4,w4 it is still lower and narrower2 so much so1 that it is only for an hour or so after sunrise or before sunset that it can be traced at all4 ,on every side1 with the exception of the curved piece on the ,s41 the wall consists of linear sections4 ,the interior contains a great number of little craters and very low longitudinal mounds4 ,ten craters are shown in ,beer and ,madler's map4 ,schmidt only draws fifteen1 though in the text accompanying his chart he says that he once counted fifty4 ,in the monograph published in the ,journal of the ,liverpool ,astronomical ,society 7vol4 v4 part #h71 forty-one are represented4 ,they appear to be rather more numerous on the ,s4 half of the floor than elsewhere4 ,just beyond the limits of the border on the ,n41 is a bright crater with a much larger obscure depression on the ,w4 of it4 ,the former is surrounded by a multitude of minute craters and crater-cones1 which are easily seen under a low sun4 ,though almost every trace of ,stadius disappears under a high light1 ,i have had little difficulty in seeing portions of the border and some of the included details when the morning terminator had advanced as far as the ,e4 wall of ,herodotus1 and the site was traversed by innumerable light streaks radiating from ,copernicus4 ,at this phase the bright crater1 just mentioned1 on the ,n4 edge of the border was tolerably distinct4 ,,copernicus4--,this is without question the grandest object1 not only on the second ,quadrant1 but on the whole visible superficies of the moon4 ,it undoubtedly owes its supremacy partly to its comparative isolation on the surface of a vast plain1 where there are no neighbouring formations to vie with it in size and magnificence1 but partly also to its favourable position1 which is such1 that1 though not central1 is sufficiently removed from the limb to allow all its manifold details to be critically examined without much foreshortening4 ,there are some other formations1 ,langrenus and ,petavius1 for example1 which1 if they were equally well situated1 would probably be fully as striking2 but1 as we see it ,copernicus is par excellence the monarch of the lunar ring-mountains4 ,schmidt remarks that this incomparable object combines nearly all the characteristics of the other ring-plains1 and that careful study directed to its unequalled beauties and magnificent form is of much more value than that devoted to a hundred other objects of the same class4 ,it is fully #ef miles in diameter1 and1 though generally described as nearly circular1 exhibits very distinctly under high powers a polygonal outline1 approximating very closely to an equilateral hexagon4 ,there are1 however1 two sections of the crest of the border on the ,n4,e4 which are inflected slightly towards the centre1 a peculiarity already noticed in the case of ,eratosthenes4 ,the walls1 tolerably uniform in height1 are surmounted by a great number of peaks1 one of which on the ,w41 according to ,neison1 stands #aa1jjj feet above the floor1 and a second on the opposite side is nearly as high4 ,both the inner and outer slopes of this gigantic rampart are very broad1 each being fully #aj miles in width4 ,the outer slope1 especially on the ,e41 is a fine object at sunrise1 when its rugged surface1 traversed by deep gullies1 is seen to the best advantage4 ,the terraces and other features on the bright inner declivities on this side may be well observed when the sun's altitude is about #f deg4 ,schmidt1 whose measures differ from those of ,neison1 estimates the height of the wall on the ,e4 to be #ab1jjj feet1 and states that the interior slopes vary from #fj deg4 to #ej deg4 above1 to from #aj deg4 to #b deg4 at the base4 ,the first inclination of #ej deg41 and in some cases of #fj deg41 is confined to the loftiest steep crests and to the flanks of the terraces4 ,there are apparently five bright little mountains on the floor1 the most easterly being rather the largest1 and a great number of minute hillocks on the ,s4,e4 quarter4 ,s4,w4 of the centre is a little crater1 and on the same side of the interior a curious hook-shaped ridge1 projecting from the foot of the wall1 and extending nearly halfway across the floor4 ,the region surrounding ,copernicus is one of the most remarkable on the moon1 being everywhere traversed by low ridges1 enclosing irregular areas1 which are covered with innumerable craterlets1 hillocks1 and other minute features1 and by a labyrinth of bright streaks1 extending for hundreds of miles on every side1 and varying considerably both in width and brilliancy4 ,the notable crater-row on the ,w41 often utilised by observers for testing the steadiness of the air and the definition of their telescopes1 should be examined when it is on the morning terminator1 at which time ,webb's homely comparison1 a mole-run with holes in it1 will be appreciated1 and its evident connection with the ,e4 side of ,stadius clearly made out4 ,there is another much more delicate row running closely parallel to this object2 it lies a little ,w4 of it1 and extends farther in a northerly direction4 ,,archimedes4--,next to ,plato the finest object on the ,mare ,imbrium4 ,it is about #ej miles in diameter4 ,the average height of its massive border is about #djjj feet above the interior1 which is only depressed some #ejj or #fjj feet below the ,mare1 the highest peak 7about #gjjj feet7 being on the ,s4,e4 ,the walls are terraced1 and include much detail1 both within and without4 ,the most noteworthy features in connection with this formation are the crater-cones1 craterlets1 pits1 white spots1 and light streaks which figure on the otherwise smooth interior4 ,mr4 ,t4,p4 ,gray1 ,f4,r4,a4,s41 of ,bedford1 who1 with praiseworthy assiduity1 has devoted more than ten years to the close scrutiny of these features1 ,mr4 ,stanley ,williams1 and others1 have detected four crater-cones on the ,e4 half of the floor1 and about fifty minute craters and white spots1 also probably volcanic vents1 and a very curious and interesting series of light streaks1 mostly traversing the formation from ,e4 to ,w4 ,a little ,e4 of the centre is a dusky oval area about #f miles across1 and ,s4,w4 of this is another1 much smaller4 ,under some conditions of illumination the two principal light markings may be traced over the ,w4 wall1 and for some distance on the plain beyond4 ,on the southern side of ,archimedes is a very rugged mountain region1 extending for more than #ajj miles towards the south3 on the ,w4 of this originates a remarkable rill-system1 best seen under evening illumination4 ,the two principal clefts follow a nearly parallel course up to the face of the ,apennines near ,mount ,bradley1 crossing in their way1 almost at right angles1 other clefts which run at no great distance from the ,e4 foot of this range and ramify among the outlying hills4 ,archimedes ,a is a brilliant little ring-plain on the ,s4,e4 of ,archimedes4 ,it casts an extraordinary shadow at sunrise1 and has a well-marked crater-row on the ,e4 of it1 and two long narrow valleys1 one of which appears to be a southerly extension of the row4 ,,beer4--,a very bright little crater1 with an unnamed formation of about the same size adjoining it on the ,n41 with which is associated a curious winding ridge that appears to traverse a gap in its ,n4 wall4 ,,timocharis4--,a fine ring-plain1 #bc miles in diameter 7the centre of a minor ray-system74 ,it stands isolated on the ,mare ,imbrium 7below the level of which it is depressed some #cjjj feet71 about midway between ,archimedes and ,lambert4 ,its walls1 rising about #gjjj feet above the floor1 are conspicuously terraced1 and on their ,w4 outer slopes exhibit some remarkable depressions4 ,there is a distinct break on the ,n41 and a bright little crater on the ,n4,w41 connected with the foot of the glacis by a prominent ridge4 ,on the bright central mountain1 ,schmidt1 in #ahdb1 detected a crater1 which is easily seen under a moderately high light4 ,timocharis and the neighbourhood1 especially the peculiar shape of the terminator on the ,e4 of the formation1 is well worth examination at sunrise4 ,,piazzi ,,smyth4--,a conspicuous little ring-plain1 #e or #f miles in diameter1 depressed about #aejj feet below the ,mare ,imbrium1 with a border rising about #bjjj feet above it4 ,with the curious arrangement of ridges1 of which it is the apparent centre1 it is a striking object under a low sun4 ,,kirch4--,a rather smaller object of the same class on the ,s4,e4 ,,plato4--,this beautiful walled-plain1 #fj miles in diameter1 with its bright border and dark steel-grey floor1 has1 from the time of ,hevelius to the present1 been one of the most familiar objects to lunar observers4 ,in the rude maps of the seventeenth century it figures as the ,lacus ,niger ,major1 an appellation which not inaptly describes its appearance under a high sun1 when the sombre tone of its apparently smooth interior is in striking contrast to that of the isthmus on which the formation stands4 ,it will repay observation under every phase1 and though during the last thirty years no portion of the moon has been more diligently scrutinised than the floor2 the neighbourhood includes a very great number of objects of every kind1 which1 not having received so much attention1 will afford ample employment to the possessor of a good telescope during many lunations4 ,the border of ,plato1 varying in height from #cjjj to #djjj feet above the interior1 is crowned by several lofty peaks1 the highest 7#gdjj feet7 standing on the ,n4 side of the curious little triangular formation on the ,e4 wall4 ,those on the ,w41 three in number1 reckoning from ,n4 to ,s41 are respectively about #ejjj1 #fjjj1 and #gjjj feet in altitude above the floor4 ,the circumvallation being very much broken and intersected by passes1 exhibits many distinct breaches of continuity1 especially on the ,s4 ,there is a remarkable valley on the ,s4,w41 which1 cutting through the border at a wide angle1 suddenly turns towards the ,s4,e41 and descends the slope of the glacis in a more attenuated form4 ,another but shorter valley is traceable at sunrise on the ,w4 ,on the ,n4,w41 the rampart is visibly dislocated1 and the gap occupied by an intrusive mountain mass4 ,this dislocation is not confined to the wall1 but1 under favourable conditions1 may be traced across the floor to the broken ,s4,e4 border4 ,it is probably a true fault4 ,on the ,n4,e41 the inner slope of the wall is very broad1 and affords a fine example of a vast landslip4 ,the spots and faint light markings on the floor are of a particularly interesting character4 ,during the years #ahfi to #ahga they were systematically observed and discussed under the auspices of the ,lunar ,committee of the ,british ,association4 ,among the forty or more spots recorded1 six were found to be crater-cones4 ,the remainder--or at least most of them--are extremely delicate objects1 which vary in visibility in a way that is clearly independent of libration or solar altitude2 and1 what is also very suggestive1 they are always found closely associated with the light markings1--standing either upon the surface of these features or close to their edges4 ,recent observations of these spots with a #ac inch telescope by ,professor ,w4,h4 ,pickering1 under the exceptionally good conditions which prevail at ,arequipa1 ,peru1 have revived interest in the subject1 for they tend to show that visible changes have taken place in the aspect of the principal crater-cones and of some of the other spots since they were so carefully and zealously scrutinised nearly a quarter of a century ago4 ,the gradual darkening of the floor of ,plato as the sun's altitude increases from #bj deg4 till after full moon may be regarded as an established fact1 though no feasible hypothesis has been advanced to account for it4 ,on the ,n4,e4 of ,plato is a large bright crater1 ,a2 and1 extending in a line from this towards the ,e41 is a number of smaller rings1 the whole group being well worth examination4 ,on the ,n4 there is a winding cleft1 and some short crossed clefts in the rugged surface just beyond the foot of the wall1 which ,i have seen with a #d inch achromatic4 ,the region on the ,w41 imperfectly shown in the maps1 includes much unrecorded detail4 ,on the ,mare ,imbrium ,s4 of ,plato is a large area enclosed by low ridges1 to which ,schroter gave the name ,newton4 ,it suggests the idea that it represents the ruin of a once imposing enclosure1 of which the conspicuous mountain ,pico formed a part4 ,,timaeus4--,a very bright ring-plain1 #bb miles in diameter1 with walls about #dejj feet in height1 on the coast-line of the ,mare ,frigoris1 and associated with the ,e4 side of the great enclosed plain ,w4,c4 ,bond4 ,schmidt shows a double hill1 nearly central1 and ,neison a crater on the ,s4,w4 wall4 ,,birmingham4--,a large rhomboidal-shaped enclosure1 defined by mountain chains and traversed by a number of very remarkable parallel ridges4 ,it is situated nearly due ,n4 of ,plato on the ,n4 edge of the ,mare ,frigoris1 and lies on the ,s4,e4 side of ,w4,c4 ,bond1 to which it bears a certain resemblance4 ,this region is characterised by the parallelism displayed by many formations1 large and small4 ,it is more apparent hereabouts than in any other part of the moon's visible surface4 ,when favourably placed under a low morning sun1 ,birmingham is a striking telescopic object4 ,,fontinelle4--,a fine ring-plain1 #bc miles in diameter1 on the ,n4 margin of the ,mare ,frigoris1 ,n4,n4,e4 of ,plato1 with a wall rising on the ,e41 #fjjj feet above a bright interior4 ,i find its border indistinct and nebulous1 excepting under very oblique light1 though three of the little craters upon it are bright and prominent4 ,one stands on the ,s41 another on the ,n4,w41 and a third on the ,e4 ,schmidt shows only the first of these1 and ,neison none of them4 ,fontinelle has a low central mountain which is easily distinguished4 ,fontinelle ,a1 an isolated mountain on the ,s41 is more than #cjjj feet high4 ,on the ,n4 there is a curious mountain group1 also of considerable altitude1 and on the ,w4 an irregular depression surrounded by a dusky area4 ,north of ,fontinelle1 extending towards ,goldschmidt and the limb1 ,schroter discovered a very wide irregular valley which he named ,j4,j4 ,cassini4 ,it is really nothing more than a great plain bounded by ridges4 ,at #i h4 ,october #ae1 #ahhh1 when ,philolaus was on the morning terminator1 ,i had a fine view of it1 and1 as regards its general shape1 found that it agreed very closely with ,schroter's drawing4 ,,epigenes4--,a remarkable ring-plain1 about #bf miles in diameter1 abutting on a mountain ridge running parallel to the ,e4 flank of ,w4,c4 ,bond4 ,it is a notable object under a low morning sun4 ,there are several elevations on the floor4 ,,goldschmidt4--,a great abnormally-shaped enclosure with lofty walls between ,epigenes and the limb4 ,neison mentions only two crater-pits within4 ,i have seen the rimmed crater shown by ,schmidt on the ,w4 side and three or four other objects of a doubtful kind4 ,,anaxagoras4--,a brilliant ring-plain of regular form1 #cb miles in diameter1 adjoining ,goldschmidt on the ,e4 ,it is a prominent centre of light streaks1 some of which traverse the interior of ,goldschmidt4 ,on the north a peak rises to the height of #aj1jjj feet4 ,there is a long ridge on the floor1 running from ,e4 to ,w4 ,,gioja4--,a ring-plain about #bf miles in diameter1 near the north pole4 ,,east ,,longitude #bj deg4 ,,to #dj deg4 ,,reinhold4--,a prominent ring-plain1 #ca miles in diameter1 with a lofty border1 rising at a peak on the ,w4 to more than #ijjj feet above the floor4 ,its shape on the ,w4 is clearly polygonal1 the wall consisting of three rectilineal sections1 and on the ,e4 it is made up of two straight sections connected by a curved section4 ,the inner slope includes a remarkably distinct and regular terrace1 the ,e4 portion of which is well seen when the interior is about half illuminated by the rising sun4 ,at this phase also the great extent of the glacis on the ,s4,w41 and the deep wide gullies traversing it on the ,e4 are observed to the best advantage4 ,the central mountain1 though of considerable size1 is not prominent4 ,close to ,reinhold on the ,n4,w4 stands a noteworthy little formation with a low and partially lineal wall1 exhibiting a gap on the north4 ,there is a distinct crater on the ,s4 side of its floor4 ,,gay-,,lussac4--,a very interesting ring-plain1 #ae miles in diameter1 situated in the midst of the ,carpathian ,highlands ,n4 of ,copernicus1 with a smaller but brighter and deeper formation 7,gay-,lussac ,a7 on the ,s4,w4 of it1 and a conspicuous little crater1 not more than #b or #c miles in diameter1 between the two4 ,the interior of ,gay-,lussac is traversed by two coarse clefts1 lying nearly in a meridional direction4 ,the more easterly runs from the foot of the ,s4 wall1 near the little crater just mentioned1 across the floor to the low ,n4 border1 which it apparently cuts through1 and extends for some distance beyond1 terminating in a great oval expansion4 ,the other1 which is not shown in the maps1 is closely parallel to it1 and can be traced up to the ,n4 border1 but not farther4 ,schmidt represents the first as a crater-row1 which it probably is1 as it varies considerably in width4 ,from the ,s4,e4 side of the formation extends a long cleft1 terminating at the end of a prominent spur from the ,s4 side of the ,carpathians4 ,there are also two remarkable rill-like valleys1 commencing on the ,n4 of ,gay-,lussac ,a1 which curve round the ,w4 side of ,gay-,lussac4 ,,hortensius4--,this brilliant crater1 about #aj miles in diameter1 is remarkable for its depth1 and as being a ray-centre surrounded by a nimbus of light4 ,it has a central mountain1 and ,schmidt shows a minute crater on the outer slope of the ,s4 wall4 ,the former is a test object4 ,,milichius4--,is situated on the ,n4,n4,e4 of ,hortensius4 ,it is fully as bright1 but rather smaller4 ,its floor1 apparently devoid of detail1 is considerably depressed below the surrounding surface4 ,,tobias ,,mayer4--,like ,gay-,lussac1 a noteworthy ring-plain associated with the ,carpathian ,mountains4 ,it is #bb miles in diameter1 and has a wall which rises on the ,w4 to a height of nearly #aj1jjj feet above the floor2 on the latter there is a conspicuous central mountain1 and on the ,e4 side a crater1 and some little hills4 ,schmidt shows a smaller crater on the ,w4 side1 which ,i have not seen4 ,adjoining the formation on the ,w4 is a ring- plain of about one-fourth its area1 which is a bright object4 ,tobias ,mayer and the neighbouring ,carpathians form an especially beautiful telescopic picture at sunrise4 ,,kunowsky4--,an inconspicuous ring-plain1 about #aa miles in diameter1 standing in a barren region in the ,mare ,procellarum1 ,w4,s4,w4 of ,encke4 ,the central mountain is tolerably distinct4 ,,encke4--,a regular ring-plain1 #bj miles in diameter1 with a comparatively low border1 nowhere rising more than #ahjj feet above the interior1 which is depressed some #ajjj feet below the surrounding ,oceanus ,procellarum4 ,a lofty ridge traverses the floor from ,s4 to ,n41 bifurcating before it reaches the ,n4 wall4 ,there is a bright crater on the ,w4 wall1 and a depression on the opposite wall1 neither of which1 strange to say1 is shown on the maps4 ,encke is encircled by ridges1 which1 when it is on the morning terminator1 combine to make it resemble a large crater surrounded by a vast mountain ring4 ,,kepler4--,one of the most brilliant objects in the second quadrant1--a ring-plain about #bb miles in diameter1 with a lofty border2 a peak on the ,e4 attaining an altitude of #aj1jjj feet above the surface4 ,the wall is much terraced1 especially the outer slope on the ,w41 where a narrow valley is easily traceable4 ,though omitted from the maps1 there is a prominent circular depression on the ,w4 border1 which forms a distinct notch thereon at sunrise4 ,on the ,n41 the wall exhibits a conspicuous gap4 ,there is a central hill on the floor4 ,immediately ,e4 of ,kepler is a bright plateau1 bounded on the ,n4 by a very straight border1 with two small craters on its edge4 ,both these objects are incomplete on the ,n41 as if they had been deformed by a fault1 which has apparently affected the ,n4 end of ,kepler also4 ,kepler is the centre of one of the most extended systems of bright streaks on the moon's visible surface4 ,,bessarion4--,a bright little ring-plain1 about #f miles in diameter1 in the ,oceanus ,procellarum ,n4 of ,kepler4 ,there is a smaller and still brighter companion on the ,n4 7,bessarion ,e71 standing on a light area4 ,bessarion has a minute central hill1 difficult to detect4 ,,pytheas4--,a small rhomboidal-shaped ring-plain1 #ab miles in diameter1 standing in an isolated position on the ,mare ,imbrium between ,lambert and ,gay-,lussac4 ,its bright walls1 rising about #bejj feet above the ,mare1 are much terraced within1 especially on the ,e4 ,there is a bright little crater on the ,n4 outer slope1 with a short serpentine ridge running up to it from the region ,s4 of ,lambert1 and another winding ridge extending from the ,s4 wall to the ,e4 of two conspicuous craters1 standing about midway between ,pytheas and ,gay-,lussac4 ,the former bears a great resemblance to the ridge ,n4 of ,madler1 and1 like this1 appears to traverse the ,n4 border4 ,the interior of ,pytheas1 which is depressed more than #bjjj feet below the ,mare1 includes a brilliant central peak4 ,,lambert4--,a ring-plain1 #ag miles in diameter1 presenting many noteworthy features4 ,the crest of its border stands about #bjjj feet above the ,mare ,imbrium1 and more than double this height above the interior4 ,the wall is prominently terraced both within and without2 the outer slope on the ,w4 exhibiting at sunrise a nearly continuous valley running round it4 ,when near the morning terminator1 the region on the ,n4 is seen to be traversed by some very remarkable ridges and markings2 one cutting across the ,n4 wall appears to represent a fault4 ,on the ,s4 is a large polygonal enclosure formed by low ridges4 ,on the ,w41 towards ,timocharis1 is a brilliant mountain #cjjj feet high1 a beautiful little object under a low sun4 ,,leverrier4--,the more westerly of a pair of little ring-plains on the ,n4 side of the ,mare ,imbrium1 and ,s4,w4 of the ,laplace promontory4 ,it is about #aj miles in diameter1 with walls rising some #aejj feet above the ,mare1 and more than #fjjj feet above the interior1 which seems to be without a central mountain or other features4 ,schmidt shows the crater on the ,n4 rim and another on the ,s4,e4 slope1 both of which are omitted by ,neison1 though they are easy objects when ,helicon is on the morning terminator4 ,about #bj miles on the ,s4,e4 there is a very bright little crater on a faint light area4 ,,helicon4--,the companion ring-plain on the ,e4 ,it is #ac miles in diameter1 and is very similar1 though not quite so deep4 ,there is a crater on the ,s4,e4 wall1 and1 according to ,neison1 another on the outer slope of the ,n4 border4 ,webb records a central crater4 ,if ,helicon is observed when on the morning terminator1 it will be seen to be traversed by a curved ridge which cuts through the walls1 and runs up to a bright crater ,s4,e4 of ,leverrier4 ,it appears to be a fault1 whose downthrow1 though slight1 is clearly indicated by an area of lower ground on the ,e4 ,there is a great number of small craters in the neighbourhood of this formation4 ,,euler4--,the most easterly of the row of great ring-plains1 which1 beginning on the ,w4 with ,autolycus1 and followed by ,archimedes1 ,timocharis1 and ,lambert1 extends almost in a great circle from the ,n4,w4 to the ,s4,e4 side of the ,mare ,imbrium4 ,it is about #ai miles in diameter1 and is surrounded by terraced walls1 which1 though of no great height above the ,mare1 rise #fjjj feet above the floor4 ,there is a distinct little gap in the ,s4 wall1 easily glimpsed when it is close to the morning terminator1 which probably represents a small crater4 ,euler has a bright central mountain1 and is a centre of white silvery streaks4 ,,brayley4--,a very conspicuous little ring-plain ,e4,s4,e4 of ,euler1 with two smaller but equally brilliant objects of the same class situated respectively ,e4 and ,w4 of it4 ,,diophantus4--,forms with ,delisle1 its companion on the ,n41 a noteworthy object4 ,it is about #ac miles in diameter1 with a wall1 which has a distinct break in its continuity on the ,n41 rising about #bejj feet above the ,mare4 ,a rill-valley runs from the ,e4 side of the ring towards the ,w4 face of a triangular-shaped mountain on the ,e4 of a line joining the formation with ,delisle4 ,north are three bright little craters in a line1 the middle one being much the largest4 ,from the most easterly of these objects a light streak may be traced under a high sun1 extending for many miles to another small crater on the ,n4,w4 of ,diophantus1 and expanding at a point due ,n4 of the formation into a spindle-shaped marking4 ,at sunrise1 the ,w4 portion of the streak has all the appearance of a cleft1 with a branch about midway running to the ,s4 side of ,delisle4 ,under the same phase a broad band of shadow extends from the ,n4,e4 wall to the triangular mountain just mentioned1 representing a very sudden drop in the surface--resembling on a small scale the well-known railroad ,e4 of ,thebit4 ,diophantus has no central mountain4 ,,delisle4--,a larger and more irregularly-shaped object than the last1 #af miles in diameter1 with loftier and more massive walls1 and an extensive but ill-defined central hill4 ,there is an evident break in the northern border4 ,a triangular mountain on the ,s4,e4 and a winding ridge running up to the ,n4 wall are prominent features at sunrise1 as are also the brilliant summits of a group of hills some distance to the ,e4,n4,e4 ,,carlini4--,a small but prominent and deep little crater about #e miles in diameter on the ,mare ,imbrium about midway between ,lambert and the ,sinus ,iridum4 ,there are many faint light streaks in the vicinity1 one of which extends from ,carlini to ,bianchini1 on the edge of the ,sinus1--a distance of #cjj miles4 ,schmidt shows a central peak4 ,,caroline ,,herschel4--,a bright and very deep ring-plain about #h miles in diameter on the ,mare ,imbrium1 some distance ,e4,n4,e4 of the last4 ,on the ,s4,e4 lies a larger crater1 ,delisle ,b1 which has a small but obvious crater on its ,n4 rim1 and casts a very prominent shadow at sunrise4 ,caroline ,herschel stands on a long curved ridge running ,n4,e4 from ,lambert towards the region ,e4 of ,helicon1 and1 according to ,schmidt1 has a central peak4 ,on the ,e4 is a bright mountain with two peaks2 some distance ,n4 of which is a large ill-defined white spot1 with another spot of a similar kind on the ,w4 of it1 nearly due ,n4 of ,caroline ,herschel4 ,,gruithuisen4--,this ring-plain1 #aj miles in diameter1 is situated on the ,mare ,imbrium on the ,n4,e4 of ,delisle4 ,it is associated with a number of ridges trending towards the region ,n4 of ,aristarchus and ,herodotus4 ,,the ,,laplace ,,promontory4--,a magnificent headland marking the extreme western extremity of the finest bay on the moon's visible surface1 the ,sinus ,iridum2 above which it towers to a height of #ijjj feet or more1 projecting considerably in front of the line of massive cliffs which define the border of the ,sinus1 and presenting a long straight face to the ,s4,e4 ,near its summit are two large but shallow depressions1 the more easterly having a very bright interior4 ,at a lower level1 almost directly below the last1 is a third depression4 ,all three are easy objects under a low sun4 ,the best view of the promontory and its surroundings is obtained when the ,e4 side of the bay is on the morning terminator4 ,its prominent shadow is traceable for many days after sunrise4 ,,the ,,heraclides ,,promontory4--,the less lofty but still very imposing headland at the ,e4 end of the ,sinus ,iridum1 rising more than #djjj feet above it4 ,it consists of a number of distinct mountains1 forming a triangular-shaped group running out to a point at the ,s4,w4 extremity of the bay1 and projecting considerably beyond the shore-line4 ,there is a considerable crater on the ,e4 side of the headland1 not visible till a late stage of sunrise4 ,it is among the mountains composing this promontory that some ingenuity and imagination have been expended in endeavouring to trace the lineaments of a female face1 termed the ,moon- maiden4 ,,bianchini4--,a fine ring-plain1 about #ah miles in diameter1 on the ,n4,e4 side of the ,sinus ,iridum1 surrounded by the lofty mountains defining the border of the bay4 ,its walls1 which are prominently terraced within1 rise about #gjjj feet on the ,e41 and about #hjjj feet on the ,w4 above the floor1 which includes a prominent ridge and a conspicuous central mountain4 ,there is a distinct crater on the ,s4 wall1 not shown in the maps4 ,between this side of the formation and the bay is a number of hills running parallel to the shore-line3 these1 with the intervening valleys1 will repay examination at sunrise4 ,,maupertuis4--,a great mountain enclosure of irregular shape1 about #bj miles in diameter1 in the midst of the ,sinus ,iridum highlands1 ,n4 of ,laplace4 ,the walls are much broken by passes1 and the interior includes many hills and ridges4 ,,condamine4--,a rhomboidal-shaped ring-plain1 about #bc miles in diameter1 ,n4 of ,maupertuis1 with lofty walls1 especially on the ,e41 where they rise some #djjj feet above the interior4 ,there are three large depressions on the outer ,n4,w4 slope1 and at least three minute craters on the crest of the wall just above4 ,though neither ,neison nor ,schmidt draw any detail thereon1 there is a prominent ridge on the ,n4 side of the floor1 and a low circular hill on the ,s4 ,on the ,s4,e4 four long ridges or spurs radiate from the wall1 and on the ,n4,e4 are three remarkable square-shaped enclosures4 ,on the edge of the ,mare ,frigoris1 ,n4,w4 of ,condamine1 are many little craters with bright rims and a distinct short cleft1 running parallel to the coast-line4 ,the winding valleys in the region bordering the ,sinus ,iridum1 and other curious details1 render this portion of the moon's surface almost unique4 ,,bouguer4--,a bright regular little ring-plain1 about #h miles in diameter1 ,n4 of ,bianchini4 ,j4,f4,w4 ,,herschel4--,a vast enclosed plain1 about #ij miles across1 bounded on the ,w4 by a mountain range1 which here defines the ,e4 side of the ,mare ,frigoris1 on the ,s4 by massive mountains1 and on the other sides by a lofty but much broken wall1 intersected by many passes4 ,within is a large ring-plain1 nearly central1 and a large number of little craters and crater-pits4 ,the floor is traversed longitudinally by many low ridges1 lying very close together1 which at sunrise resemble fine grooves or scratches of irregular width and depth4 ,,horrebow4--,a ring-plain of remarkable shape1 resembling the analemma figure1 standing at the ,s4 end of the mountain range bounding ,j4,f4,w4 ,herschel on the ,w4 ,schmidt shows a crater on the ,w4 wall1 near the constriction on this side1 and a second at the foot of the slope of the ,e4 wall4 ,,philolaus4--,a ring-plain #df miles in diameter1 on the ,n4,e4 of ,fontinelle4 ,its bright walls rise on the ,w4 to a height of nearly #ab1jjj feet above the floor 7on which there is a conspicuous central mountain71 and exhibit many prominent terraces4 ,philolaus is partially encircled1 at no great distance1 by a curved ridge1 on which will be found a number of small craters4 ,,anaximines4--,a much foreshortened ring-plain1 about #ff miles in diameter1 on the ,e4 of ,philolaus4 ,one peak on the ,e4 is nearly #hjjj feet in height4 ,schmidt shows four craters on the ,w4 side of the floor1 and a fifth on the ,s4,e4 side4 ,there is a bright streak in the interior1 which extends southwards for some distance across the ,mare ,frigoris4 ,,east ,,longitude #dj deg4 ,,to #fj deg4 ,,reiner4--,a regular ring-plain1 #ba miles in diameter1 in the ,mare ,procellarum1 ,s4,s4,e4 of ,marius1 with a very lofty border terraced without and within1 and a minute but conspicuous mountain standing at the ,n4 end of a ridge which traverses the uniformly dark floor in a meridional direction4 ,a long ridge extends some way towards the ,s4 from the foot of the ,s4 wall1 and at some distance in the same direction lie six ill- defined white spots of doubtful nature4 ,on the ,e4,n4,e4 there is a large white marking1 resembling a ,jew's harp in shape1 and farther on1 towards the ,e41 a number of very remarkable ridges4 ,on the ,w4 will be found many bright little craterlets4 ,a ray from ,kepler extends almost up to the ,w4 wall of ,reiner4 ,,marius4--,a very noteworthy ring-plain1 #bg miles in diameter1 in the ,oceanus ,procellarum1 ,e4,n4,e4 of ,kepler1 with a bright border rising about #djjj feet above the interior1 which is of an uneven tone4 ,the rampart exhibits some breaks1 especially on the ,s4 ,the outer slope on the ,w4 is traversed by a fine deep valley1 distinctly marked when the opposite side is on the morning terminator4 ,it originates on the ,s4,w4 at a prominent crater situated a little below the crest of the wall1 and1 following its curvature1 runs out on to the plain near a large mountain just beyond the foot of the ,n4 border4 ,in addition to the crater just mentioned1 there are two smaller ones below the summit of the ,s4 wall1 and a small circular depression on the ,s4,e4 wall4 ,mr4 ,w4,h4 ,maw1 ,f4,r4,a4,s41 has seen1 with a #f inch ,cooke refractor1 a bright marking at the ,n4 extremity of the ring1 which1 when examined with a ,dawes' eyepiece1 resembled an imperfect crater4 ,the floor includes at least four objects--7#a7 ,a crater on the ,n4,w41 standing on a circular light area2 7#b7 a white spot a little ,s4 of the centre2 7#c7 a smaller white spot ,s4,e4 of this2 7#d7 another1 near the inner foot of the ,s4,w4 wall4 ,marius is an imposing object under oblique illumination1 mainly because of the number of ridges by which it is surrounded4 ,i have frequently remarked at sunrise that the surface on the ,w41 and especially the outer slope of the rampart1 is of a decided brown or sepia tint1 similar to that which has already been noticed with respect to ,geminus and its vicinity1 viewed under like conditions4 ,schmidt in #ahfb discovered a long serpentine cleft some distance ,n4 of ,marius1 which has not been seen since4 ,,aristarchus4--,the brightest object on the moon1 forming with ,herodotus 7a companion ring-plain on the ,e471 and its remarkable surroundings1 one of the most striking objects which the telescope has revealed on the visible surface1 and one requiring much patient observation before its manifold details can be fully noted and duly appreciated4 ,its border rises #bjjj feet above the outer surface on the ,w41 but towers to more than double this height above the glistening floor4 ,no lunar object of its moderate dimensions 7it is only about #bi miles in diameter7 has such conspicuously terraced walls1 or a greater number of spurs and buttresses2 which are especially prominent on the ,s4 ,a valley runs round the outer slope of the ,w4 wall1 very similar to that found in a similar position round ,marius4 ,there is also a distinct valley on the brilliant inner slope of the ,e4 wall1 below its crest4 ,it originates at a bright little crater1 and is traceable round the greater portion of the declivity4 ,under a moderately high sun1 an oval area1 nearly as large and fully as brilliant as the central mountain1 is seen on this inner slope4 ,it is bordered on either side by bands of a duskier hue1 which probably represent shallow transverse valleys4 ,from its dazzling brilliancy it is very difficult to observe the interior satisfactorily4 ,in addition1 however1 to the central mountain1 there is a crater on the ,n4,w4 side of the floor4 ,on the ,s4 side of ,aristarchus is a large dusky ring some #aj miles in diameter1 connected by ridges with the spurs from the wall1 and on the ,s4,e41 close to the foot of the slope1 is another smaller ring of a like kind4 ,,herodotus4--,this far less brilliant but equally interesting object is about #bc miles in diameter1 and is not so regular in shape as ,aristarchus4 ,its ,w4 wall rises at one point more than #djjj feet above the very dusky floor4 ,except on the ,s4,w4 and ,n4,e41 the border is devoid of detail4 ,on the ,s4,w4 three little notches may be detected on its summit1 which probably represent small craters1 while on the opposite side1 on the inner slope1 a little below the crest1 is a large crater1 easily seen4 ,both the ,e4 and ,w4 sections of the wall are prolonged towards the ,s4 far beyond the limits of the formation4 ,these rocky masses1 with an intermediate wall1 are very conspicuous under oblique illumination1 that on the ,s4,w4 being especially brilliant4 ,on the ,n4 there is a gap through which the well-known serpentine cleft passes on to the floor4 ,between the ,n4,w4 side of ,herodotus and ,aristarchus is a large plateau1 seen to the best advantage when the morning terminator lies a little distance ,e4 of the former4 ,it is traversed by a ,t-shaped cleft which communicates with the great serpentine cleft and extends towards the ,s4 end of ,aristarchus1 till it meets a second cleft 7forming the upper part of the ,t7 running from the ,s4,e4 side of this formation along the ,w4 side of ,herodotus4 ,the great serpentine cleft1 discovered by ,schroter1 ,october #g1 #aghg1 is in many respects the most interesting object of its class4 ,it commences at the ,n4 end of a short wide valley1 traversing mountains some distance ,n4,e4 of ,herodotus1 as a comparatively delicate cleft4 ,after following a somewhat irregular course towards the ,n4,w4 for about #ej miles1 and becoming gradually wider and deeper1 it makes a sudden turn and runs for about #aj miles in a ,s4,w4 direction4 ,it then changes its course as abruptly to the ,n4,w4 again for #c or #d miles1 once more turns to the ,s4,w41 and1 as a much coarser chasm1 maintains this direction for about #bj miles1 till it reaches the ,s4,e4 edge of a great mountain plateau ,n4 of ,aristarchus1 when it swerves slightly towards the ,s41 becoming wider and wider1 up to a place a few miles ,n4 of ,herodotus1 where it expands into a broad valley2 and then1 somewhat suddenly contracting in width1 and becoming less coarse1 enters the ring-plain through a gap in the ,n4 wall1 as before mentioned4 ,i always find that portion of the valley in the neighbourhood of ,herodotus more or less indistinct1 though it is broad and deep4 ,this part of it1 unless it is observed at a late stage of sunrise1 is obscured by the shadow of the mountains on the border of the plateau4 ,gruithuisen suspected a cleft crossing the region embraced by the serpentine valley1 forming a connection between its coarse southern extremity and the long straight section4 ,this has been often searched for1 but never found4 ,it may exist1 nevertheless1 for in many instances ,gruithuisen's discoveries1 though for a long time discredited1 have been confirmed4 ,the mountain plateau ,n4 of ,aristarchus deserves careful scrutiny1 as it abounds in detail and includes many short clefts4 ,,harbinger1 ,,mountains4--,a remarkable group of moderate height1 mostly extending from the ,n4,w4 towards ,aristarchus4 ,they include a large incomplete walled-plain about #cj miles in diameter1 defined on the ,w4 by a lofty border1 forming part of a mountain chain1 and open to the south4 ,this curious formation has many depressions in connection with its ,n4,w4 edge4 ,on the ,n4 of it there is a crater-row and a very peculiar zig-zag cleft4 ,the region should be observed when the ,e4 longitude of the morning terminator is about #de deg4 ,,schiaparelli4--,a conspicuous formation1 about #af miles in diameter1 between ,herodotus and the ,n4,e4 limb1 with a border rising nearly #bjjj feet above the ,mare1 and about #ajjj more above the floor1 on which ,schmidt shows a central hill4 ,,wollaston4--,a small bright crater on the ,mare ,n4 of the ,harbinger ,mountains1 surpassed in interest by a remarkable formation a few miles ,s4 of it1 ,wollaston ,b1 an object of about the same size1 but which is associated with a much larger enclosure1 resembling a walled-plain1 lying on the ,n4 side of it4 ,this formation has a lofty border on the ,w41 surmounted by two small craters4 ,the wall is lower on the ,e4 and exhibits a gap4 ,there is a central hill1 only visible under a low sun4 ,about midway between ,wollaston and this enclosure stands a small isolated triangular mountain4 ,from a hill on the ,e4 runs a rill valley to the more westerly of a pair of craters1 connected by a ridge1 on the ,s4,e4 of ,wollaston ,b4 ,,mairan4--,a bright ring-plain of irregular shape1 #be miles in diameter1 on the ,e4 of the ,heraclides promontory4 ,the border1 especially on the ,e41 varies considerably in altitude1 as is evident from its shadow at sunrise2 at one peak on the ,w4 it is said to attain a height of more than #ae1jjj feet above the interior4 ,there is a very minute crater on the crest of the ,s4 wall1 down the inner slope of which runs a rill-like valley4 ,about halfway down the inner face of the ,e4 wall are two other small craters1 connected together by a winding valley4 ,these features may be seen under morning illumination1 when about one-fourth of the floor is in sunlight4 ,schroter is the only selenographer who gives ,mairan a central mountain4 ,in this he is right4 ,i have seen without difficulty on several occasions a low hill near the centre4 ,the formation is surrounded by a number of conspicuous craters and crater-pits4 ,on the ,n4 there is a short rill-like valley1 and another1 much coarser1 on the ,s4 ,,sharp4--,a ring-plain somewhat smaller than the last1 on the ,e4 of the ,sinus ,iridum1 from the coast-line of which it is separated by lofty mountains4 ,there is a distinct crater at the foot of its ,n4,e4 wall1 and a bright central mountain on the floor4 ,on the ,n4 is a prominent enclosure1 nearly as large as ,sharp itself2 and on the ,n4,e4 a brilliant little ring- plain1 ,a1 about #h miles in diameter1 connected with ,sharp1 as ,madler shows1 by a wide valley4 ,,louville4--,a triangular-shaped formation on the ,e4 of a line joining ,mairan and ,sharp4 ,it is hemmed in by mountains1 one of which towers #ejjj feet above its dusky floor4 ,,foucault4--,a bright deep ring-plain1 about #aj miles in diameter1 lying ,e4 of the mountains fringing the ,sinus ,iridum1 between ,bianchini and ,harpalus4 ,a very lofty peak rises near its ,n4 border1 and1 according to ,neison1 it has a distinct central mountain1 though neither ,madler or ,schmidt show any detail within4 ,,harpalus4--,a conspicuous ring-plain1 about #ad miles in diameter1 on the ,n4,e4 of the last1 with a floor sinking #ac1jjj feet below the surrounding surface4 ,as the cubic contents of the border and glacis are quite inadequate to account for it1 we may ask1 what has become of the material which presumably once filled this vast depression8 ,harpalus has a bright central mountain4 ,,south4--,on the ,w4 and ,s41 the boundaries of this extensive enclosure are merely indicated by ridges1 which nowhere attain the dignity of a wall4 ,on the ,n41 the edge of a tableland intersected by a number of valleys define its limits1 and on the ,e4 a border forming also the ,w4 side of ,babbage4 ,the interior is traversed by a number of longitudinal hills1 and includes two bright little heights1 drawn by ,schmidt as craters4 ,,babbage4--,a still larger enclosed area1 adjoining ,south on the ,e41 and containing a considerable ring-plain near its ,w4 border4 ,it is a fine telescopic object at sunrise1 the interior being crossed by a number of transverse markings representing ridges4 ,these are very similar in character 7but much coarser7 to those found on the floor of ,j4,f4,w4 ,herschel4 ,the curious detail on the ,e4 wall is also worth examination at this phase4 ,,robinson4--,a bright and very deep little ring-plain1 about #ab miles in diameter1 on a plateau ,n4 of ,south4 ,schmidt shows a crater on the ,w4 border1 and two others at the foot of the ,n4 and ,e4 borders respectively4 ,,anaximander4--,a fine but much foreshortened ring-plain1 #ci miles in diameter1 abutting on the ,e4 side of ,j4,f4,w4 ,herschel4 ,it has a large crater on its ,w4 border1 which is common to the two formations1 and a very prominent crater1 both on the ,s4 and ,n4 ,the barrier on the ,s4,w4 rises to a height of nearly #aj1jjj feet4 ,schmidt shows a crater and other details on the floor4 ,,east ,,longitude #fj deg4 ,,to #ij deg4 ,,lohrmann4--,this ring-plain1 with ,hevel and ,cavalerius on the ,n4 of it1 is a member of a linear group1 which1 but for its propinquity to the limb1 would be one of the most imposing on the moon's surface4 ,lohrmann1 about #bh miles in diameter1 is surrounded by a bright wall1 which1 to all appearance1 is devoid of detail4 ,two prominent ridges1 with a fine intervening valley1 connect it with the ,n4 end of ,grimaldi4 ,it has a large but not conspicuous central mountain4 ,on the rugged surface1 between the ring-plain and the ,e4 edge of the ,oceanus ,procellarum1 lies a very interesting group of crossed clefts1 some of which run from ,n4,e4 to ,s4,w41 and others from ,n4,w4 to ,s4,e4 ,three of the latter proceed from different points in a coarse valley extending from ,w4 to ,e41 and cross the ridges just mentioned4 ,they follow a parallel course1 and terminate on the ,s4 side of a crater-row1 consisting of three bright craters ranging in a line parallel to the coarse valley4 ,on the ,n4 side of these objects1 and tangential to them1 is another cleft1 which traverses the ,w4 and ,e4 walls of ,lohrmann1 and1 crossing the region between it and ,riccioli1 terminates apparently at the ,w4 wall of the latter formation4 ,no map shows this cleft1 though it is obvious enough2 and1 when the ,e4 wall of ,hevel is on the morning terminator1 the notches made by it in the border of ,lohrmann are easily detected4 ,capt4 ,noble1 ,f4,r4,a4,s41 aptly compares two of the crossed clefts to a pair of scissors1 the craters at which they terminate representing the oval handles4 ,on the grey surface of the ,mare ,w4 of ,lohrmann is the bright crater ,lohrmann ,a1 from which1 running ,n41 proceeds a rill-like valley ending at a large white spot1 which has a glistening lustre under a high light4 ,,hevel4--,a great walled-plain1 #ga miles in diameter1 adjoining ,lohrmann on the ,n41 with a broad western rampart1 rising at one peak to a height above the interior of nearly #fjjj feet1 and presenting a steep bright face to the ,oceanus ,procellarum4 ,there are three prominent craters near its crest1 and one or two breaks in its continuity4 ,it is not so lofty and is more broken on the ,e41 where three conspicuous craters stand on its inner slope4 ,the floor is slightly convex1 and includes a triangular central mountain1 on which there is a small crater4 ,the ,s4 half of the interior is crossed by four clefts3 7l7 running from a little crater ,n4 of the central mountain1 on the ,w4 side of it1 to a hill at the foot of the ,s4,w4 wall2 7#b7 originating near the most southerly of the three craters on the inner slope of the ,e4 wall1 and crossing #a1 terminates at the foot of the ,w4 wall2 7#c7 has the same origin as #b1 crosses #a1 and1 passing over a craterlet ,w4 of the central mountain1 also runs up to the ,w4 wall at a point considerably ,n4 of that where #b joins the latter2 7#d7 runs from the craterlet just mentioned to the ,w4 end of #b4 ,,cavalerius4--,the most northerly member of the linear chain1 a ring-plain1 #da miles in diameter1 with terraced walls rising about #aj1jjj feet above the floor4 ,within there is a long central mountain with three peaks4 ,under a high light the region on the ,w4 is seen to be crossed by broad light streaks4 ,,olbers4--,a large ring-plain1 #da miles in diameter1 near the limb1 ,n4,e4 of ,cavalerius4 ,though a very distinct formation1 it is difficult to see its details except under favourable conditions of libration4 ,it has a large crater on its ,w4 wall1 a smaller one on the ,e41 and a third on the ,n4 ,the floor includes a central mountain1 and1 according to ,schmidt1 four craters4 ,he also shows a crater-rill on the ,w4 wall1 ,n4 of the large crater thereon4 ,olbers is the origin of a fine system of light rays4 ,,galileo4--,a ring-plain1 about #i miles in diameter1 ,n4,e4 of ,reiner1 associated with ridges1 some of which extend to the ,jew's ,harp marking referred to under this formation4 ,,cardanus4--,a fine regular ring-plain1 about #cb miles in diameter1 near the limb ,n4 of ,olbers4 ,its bright walls1 rising about #djjj feet above the light grey floor1 are clearly terraced1 and exhibit1 especially on the ,s4,e41 several spurs and buttresses4 ,there is a fine valley on the outer ,w4 slope1 a large bright crater on the ,mare just beyond its foot1 and a conspicuous mountain in the same position farther north4 ,i have not succeeded in seeing the faint central hill nor the crater ,n4 of it shown by ,schmidt1 but there is a brilliant white circular spot on the floor at the inner foot of the ,n4,e4 wall which he does not show4 ,,krafft4--,a very similar object on the ,n41 of about the same dimensions2 with a central peak1 and a large crater on the dark floor abutting on the ,s4,w4 wall1 and another of about half the size on the outer side of the ,w4 border4 ,from this crater a very remarkable cleft runs to the ,n4 wall of ,cardanus3 it is bordered on either side by a bright bank1 and cuts through the ,n4,w4 border of the latter formation4 ,it is best seen when the ,e4 wall of ,cardanus is on the morning terminator4 ,,vasco ,,de ,,gama4--,a bright enclosure1 #ea miles in diameter1 with a small central mountain4 ,it is associated on the ,n4 with a number of enclosed areas of a similar class1 all too near the limb to be well seen4 ,,seleucus4--,a considerable ring-plain1 #cb miles in diameter1 with lofty terraced walls1 rising #aj1jjj feet above a dark floor which includes an inconspicuous central hill4 ,this formation stands on a ridge extending from near ,briggs to the ,w4 side of ,cardanus4 ,,otto ,,struve4--,an enormous enclosure1 bounded on the ,e4 by the ,hercynian ,mountains1 and on the ,w4 by a mountain chain of considerable altitude1 surmounted by three or more bright little rings4 ,on the ,w4 side of the uneven-toned interior1 which1 according to ,madler1 includes an area of more than #bf1jjj square miles1 stand four craters1 several little hills1 and light spots4 ,on the ,w4 is the much more regular and almost as large formation1 ,otto ,struve ,a1 the ,w4 border of ,otto ,struve forming its ,e4 wall4 ,this enclosure is bounded elsewhere by a very low1 broken1 and attenuated barrier4 ,at sunrise the ,e4 and ,w4 walls1 with the mountain mass at the ,n4 end1 which they join1 resemble a pair of partially-opened calipers4 ,there is one conspicuous little crater on the ,w4 side of the floor2 and1 at or near full moon1 four or five white spots1 nearly central1 are prominently visible4 ,,briggs4--,this bright regular ring-plain1 #cc miles in diameter1 is situated a short distance ,n4 of ,otto ,struve ,a4 ,a long ridge traverses the interior from ,n4 to ,s4 ,on the ,e4 is another large enclosure1 communicating with ,otto ,struve on the ,s41 and really forming a ,n4 extension of this formation4 ,it has a large and very deep crater1 #ab miles in diameter1 on its ,w4 border4 ,,lichtenberg4--,a conspicuous little ring-plain1 about #ab miles in diameter1 in an isolated position on the ,mare1 some distance ,n4 of ,briggs4 ,it was here that ,madler records having occasionally noticed a pale reddish tint1 which1 though often searched for1 has not been subsequently seen4 ,,ulugh ,,beigh4--,a good-sized ring-plain1 ,e4 of the last1 with a bright border and central mountain4 ,too near the limb for observation4 ,,lavoisier4--,a small bright walled-plain ,n4 of ,ulugh ,beigh4 ,it has a somewhat dark interior4 ,west of it is ,lavoisier ,a1 a ring-plain about #ad miles in diameter4 ,both are too near the limb for useful observation4 ,,gerard4--,a large enclosure close to the limb1 still farther ,n41 containing a long ridge and a crater4 ,,harding4--,a small ring-plain ,w4 of ,gerard1 remarkable for the peculiar form of its shadow at sunrise1 and for the ridges in its vicinity4 ,,repsold4--,the largest of a group of walled enclosures1 close to the limb1 on the ,e4 side of the ,sinus ,roris4 ,,xenophanes4--,but for its position1 this deep walled-plain1 #ahe miles in diameter1 would be a fine telescopic object1 with its lofty walls1 large central mountain1 and other details4 ,,oenopides4--,a large and tolerably regular walled-plain1 #dc miles in diameter1 on the ,w4 of the last4 ,the depressions on the ,w4 wall are worth examination at sunrise4 ,there is apparently no detail whatever on the floor4 ,,cleostratus4--,a small ring-plain1 ,n4 of ,xenophanes1 surrounded by a number of similar objects1 all too near the limb for observation4 ,,pythagoras4--,a noble walled-plain1 #ie miles in diameter1 which no one who observes it fails to lament is not nearer the centre of the disc1 as it would then undoubtedly rank among the most imposing objects of its class4 ,even under all the disadvantages of position1 it is by far the most striking formation in the neighbourhood4 ,its rampart rises1 at one point on the ,n41 to a height of nearly #ag1jjj feet above the floor1 on which stands a magnificent central mountain1 familiar to most observers4 ,,third ,,quadrant ,,east ,,longitude #j deg4 ,,to #bj deg4 ,,mosting4--,a very deep ring-plain1 #ae miles in diameter1 near the moon's equator1 and about #f deg4 ,e4 of the first meridian4 ,there is a crater on the ,n4 side of its otherwise unbroken bright border1 an inconspicuous central mountain1 and1 according to ,neison1 a dark spot on the ,s4 side of the floor4 ,at some distance on the ,s4,s4,w41 stands the bright crater1 ,mosting ,a1 one of the most brilliant objects on the moon's visible surface4 ,,reaumur4--,a large pentagonal enclosure1 about #cj miles in diameter1 with a greatly broken border1 exhibiting many wide gaps1 situated on the ,e4 side of the ,sinus ,medii1 ,n4,w4 of ,herschel4 ,the walls are loftiest on the ,s4 and ,s4,w41 where several small craters are associated with them4 ,a ridge connects the formation with the great deep crater ,reaumur ,a1 and a second large enclosure lying on the ,w4 side of the well-known valley ,w4 of ,herschel4 ,at the end of a spur on the ,s4 side of the great crater originates a cleft1 which ,i have often traced to the ,n4,w4 wall of ,ptolemaeus1 and across the ,n4 side of the floor of this formation to a crater on the ,n4,e4 quarter of it1 ,ptolemaeus d4 ,there is a short cleft on the ,w4 side of the floor of ,reaumur1 running from ,n4 to ,s4 ,,herschel4--,a typical ring-plain1 situated just outside the ,n4 border of ,ptolemaeus1 with a lofty wall rising nearly #aj1jjj feet above a somewhat dusky floor1 which includes a prominent central mountain4 ,its bright border is clearly terraced both within and without1 the terraces on the inner slope of the ,w4 wall being beautifully distinct even under a high light1 and on the outer slope are some curious irregular depressions4 ,on the ,s4,s4,e4 is a large oblong deep crater1 close to the rocky margin of ,ptolemaeus1 and a little beyond the foot of the wall on the ,n4,w4 is a smaller and more regular rimmed depression1 b1 standing near the ,e4 border of the great valley1 more than #hj miles long1 and in places fully #aj miles wide1 which runs from ,s4,s4,w4 to ,n4,n4,e4 on the ,w4 side of ,herschel1 and bears a close resemblance to the well-known ,ukert ,valley4 ,herschel d is a large but shallow ring-plain on the ,e4 of ,herschel1 with a brilliant but smaller crater on the ,w4 of it4 ,north of ,herschel1 on a plateau concentric with its outline1 stands the large polygonal ring-plain ,herschel a1 a formation of a very interesting character1 with a low broken wall1 exhibiting many gaps1 and including some craters of a minute class4 ,the largest of these stands on the ,s4,w4 wall4 ,mr4 ,w4,h4 ,maw has detected some of these objects on the ,n4 side1 both in connection with the border and beyond it4 ,,flammarion4--,a large incomplete walled-plain ,n4,e4 of ,herschel1 open towards the ,n41 with a border rising about #cjjj feet above the floor4 ,the brilliant crater1 ,mosting ,a1 stands just outside the wall on the ,e4 ,,ptolemaeus4--,taking its very favourable position into account1 this is undoubtedly the most perfect example of a walled-plain on the moon's visible superficies4 ,it is the largest and most northerly component of the fine linear chain of great enclosures1 which extend southwards1 in a nearly unbroken line1 to ,walter4 ,it exhibits a very marked departure from circularity1 the outline of the border approximating in form to a hexagon with nearly straight sides4 ,it includes an area of about #ijjj square miles1 the greatest distance from side to side being about #aae miles4 ,it is1 in fact1 about equal in size to the counties of ,york1 ,lancashire1 and ,westmorland combined2 and were it possible for one to stand near the centre of its vast floor1 he might easily suppose that he was stationed on a boundless plain2 for1 except towards the west1 not a peak1 or other indication of the existence of the massive rampart would be discernible2 and even in this direction he would only see the upper portion of a great mountain on the wall4 ,the border is much broken by gaps and intersected by passes1 especially ,e4 and ,s41 where there are several valleys connecting the interior with that of ,alphonsus4 ,the loftiest portion of the wall1 which includes many crateriform depressions1 is on the ,w41 where one peak rises to nearly #ijjj feet4 ,another on the ,n4,e4 is about #fjjj feet above the interior4 ,on the ,n4,w4 is a remarkable crater-row1 called1 from its discoverer1 ,webb's furrow1 running from a point a little ,n4 of a depression on the border to a larger crateriform depression on the ,s4 of ,hipparchus ,k4 ,birt terms it a very fugitive and delicate lunar feature4 ,as regards the vast superficies enclosed by this irregular border1 it is chiefly remarkable for the number of large saucer-shaped hollows which are revealed on its surface under a low sun4 ,they are mostly found on the eastern quarter of the floor4 ,some of them appear to have very slight rims1 and in two or three instances small craters may be detected within them4 ,owing to their shallowness1 they are very evanescent1 and can only be glimpsed for an hour or so about sunrise or sunset4 ,the large bright crater ,a1 about #d miles in diameter on the ,n4,w4 side of the interior1 is by far the most conspicuous object upon it4 ,adjoining it on the ,n4 is a large ring with a low border1 and ,n4 of this again is another1 extending to the wall4 ,mr4 ,maw and ,mr4 ,mee have seen minute craters on the borders of these obscure formations4 ,in addition to the objects just specified1 there is a fairly conspicuous crater1 d1 on the ,n4,e4 quarter of the floor1 and a very large number of others distributed on its surface1 which is also traversed by a network of light streaks1 that have recently been carefully recorded by ,mr4 ,a4,s4 ,williams4 ,a cleft1 from near ,reaumur ,a1 traverses the ,n4 side of the floor1 and runs up to ,ptolemaeus d4 ,,alphonsus4--,a large walled-plain1 #hc miles in diameter1 with a massive irregular border abutting on the ,s4,s4,e4 side of ,ptolemaeus1 and rising at one place on the ,n4,w4 to a height of #gjjj feet above the interior4 ,the floor presents many features of interest4 ,it includes a bright central peak1 forming part of a longitudinal ridge1 on either side of which runs a winding cleft1 originating at a crater-row on the ,n4 side of the interior4 ,there is a third cleft on the ,n4,w4 side1 and a fourth near the foot of the ,e4 wall4 ,there are also three peculiar dark areas within the circumvallation2 two1 some distance apart1 abutting on the ,w4 wall1 and a third1 triangular in shape1 at the foot of the ,e4 wall4 ,the last- mentioned cleft traverses this patch4 ,these dusky spots are easily recognised in good photographs of the moon4 ,,alpetragius4--,a fine object1 #bg miles in diameter1 closely connected with the ,s4,e4 side of ,alphonsus4 ,it has peaks on the ,w4 towering #ab1jjj feet above the floor1 on which there is an immense central mountain1 which in extent1 complexity1 and altitude surpasses many terrestrial mountain systems--as1 for example1 the ,snowdonian group4 ,the massive barrier between ,alpetragius and ,alphonsus deserves careful scrutiny1 and should be examined under a moderately low morning sun4 ,on the ,e41 towards ,lassell1 stands a brilliant light-surrounded crater4 ,,arzachel4--,another magnificent object1 associated on the ,n4 with ,alphonsus1 about #ff miles in diameter1 and encircled by a massive complex rampart1 rising at one point more than #ac1jjj feet above a depressed floor4 ,it presents some very suggestive examples of terraces and large depressions1 the latter especially well seen on the ,s4,e4 ,the bright interior includes a large central mountain with a digitated base on the ,s4,e41 some smaller hills on the ,s4 of it1 a deep crater ,w4 of it 7with small craters ,n4 and ,s471 and1 between the crater and the foot of the ,w4 wall1 a very curious winding cleft4 ,,lassell4--,this ring-plain1 some #ad miles in diameter1 is irregular both as regards its outline and the width of its rampart4 ,there is a crater on the crest of the ,n4,w4 wall1 just above a notable break in its continuity through which a ridge from the ,n4,w4 passes4 ,there is another crater on the opposite side4 ,the central mountain is small and difficult to see4 ,about #bj miles ,n4,e4 of ,lassell is a remarkable mountain group associated with a bright crater1 and further on in the same direction is a light oval area1 about #aj miles across1 with a crater 7,alpetragius d7 on its ,s4 edge4 ,madler described this area as a bright crater1 #e miles in diameter1 which now it certainly is not4 ,,lalande4--,a very deep ring-plain1 about #ad miles in diameter1 ,n4,e4 of ,ptolemaeus1 with bright terraced walls1 some #fjjj feet above the floor1 which contains a low central mountain4 ,on the ,n4 is the long cleft running1 with some interruptions1 in a ,w4,n4,w4 direction towards ,reaumur4 ,,davy4--,a deep irregular ring-plain1 #bc miles across1 on the ,mare ,e4 of ,alphonsus4 ,there is a deep crater with a bright rim on its ,s4,w4 wall1 and ,e4 of this a notable gap4 ,there is also a wide opening on the ,n4 ,the ,e4 wall is of the linear type4 ,a cleft crosses the interior4 ,,guerike4--,the most southerly member of a remarkable group of partially destroyed walled-plains1 standing in an isolated position in the ,mare ,nubium4 ,its border1 on the ,w4 and ,n4 especially1 is much broken1 and never rises much more than #bjjj feet above the ,mare1 except at one place on the ,n41 where there is a mountain about #ajjj feet higher4 ,the ,e4 wall is tolerably continuous1 but is of a very abnormal shape4 ,on the ,s4 there is a peculiar ,,lambda-shaped gap 7with a bright crater1 and another less prominent on the ,e4 side of it71 the narrowest part of which opens into a long wide winding valley1 bounded by low hills1 extending to the ,w4 side of a bright ring-plain1 ,guerike ,b1 on the ,s4,e4 ,a crater-chain occupies the centre of this valley4 ,there is much detail within ,guerike4 ,a large deep bright crater stands under the ,e4 border on a mound1 which1 gradually narrowing in width1 extends to the ,n4 wall2 and a rill-like valley runs from the ,n4 border towards the ,e4 side of the ,,lambda-shaped gap4 ,in addition to these features1 there is a shallow rimmed crater1 about midway between the extremities of the rill-valley1 and several minor elevations on the floor4 ,on the broken ,n4 flank of ,guerike is a number of incomplete little rings1 all open to the ,n42 and ,e4 of these commences a linear group of lofty isolated mountain masses extending towards the ,w4 side of ,parry1 and prolonged for #cj miles or more towards the north4 ,they are arranged in parallel rows1 and remind one of a ,druidical avenue of gigantic monoliths viewed from above4 ,they terminate on the ,s4 side of a large bright incomplete ring 7with a lofty ,w4 wall71 connected with the ,w4 side of ,parry4 ,,parry4--,a more complete formation than ,guerike4 ,it is about #be miles in diameter1 and is encompassed by a bright border1 which1 at a point on the ,e41 is nearly #ejjj feet in height4 ,it is intersected on the ,n4 by passes communicating with the interior of ,fra ,mauro4 ,there is a crater1 nearly central1 on the dusky interior1 which1 under a low sun1 when the shadows of the serrated crest of the ,w4 wall reach about half-way across the floor1 appears to be the centre of three or four concentric ridges1 which at this phase are traceable on the ,e4 side of it4 ,there is a conspicuous crater on the ,e4 wall1 below which originates a distinct cleft4 ,this object skirts the inner foot of the ,e4 border1 and after traversing the ,n4 wall1 strikes across the wide expanse of ,fra ,mauro1 and is ultimately lost in the region ,n4 of this formation4 ,parry ,a1 ,s4 of ,parry1 is a very deep brilliant crater with a central hill and surrounded by a glistening halo4 ,a cleft1 originating at a mountain arm connected with the ,e4 side of ,guerike1 runs to the ,s4 flank of this object1 and is probably connected with that which skirts the floor of ,parry on the ,e4 ,,bonpland4--,a ruined walled-plain with a low and much broken wall1 which on the ,s4,w4 appears to be an attenuated prolongation of that of ,parry4 ,it is of the linear type1 the formation approximating in shape to that of a pentagon4 ,the floor is crossed from ,n4 to ,s4 by a fine cleft which originates at a crater beyond the ,s4 wall1 and is visible as a light streak under a high light4 ,schmidt shows a short cleft on the ,w4 of this4 ,,fra ,,mauro4--,a large enclosure of irregular shape1 at least #ej miles from side to side1 abutting on ,parry and ,bonpland4 ,in addition to the cleft which crosses it1 the floor is traversed by a great number of ridges1 and includes at least seven craters4 ,,thebit4--,a fine ring-plain1 #cb miles in diameter1 on the mountainous ,w4 margin of the ,mare ,nubium1 ,n4,e4 of ,purbach4 ,its irregular rampart is prominently terraced1 and its continuity on the ,n4,e4 interrupted by a large deep crater 7,thebit ,a71 at least #i miles in diameter1 which has in its turn a smaller crater1 of about half this size1 on its margin1 and a small central mountain within1 which was once considered a good optical test1 though it is not a difficult object in a #d inch achromatic1 if it is looked for at a favourable phase4 ,the border of ,thebit rises at one place on the ,n4,w4 to a height of nearly #aj1jjj feet above the interior1 which includes much detail4 ,the ,e4 wall of ,thebit ,a attains the same height above its floor1 which is depressed more than #ejjj feet below the ,mare4 ,,birt4--,this ring-plain1 about #ab miles in diameter1 is situated on the ,mare ,nubium1 some distance due ,e4 of ,thebit4 ,it has a brilliant border1 surmounted by peaks rising more than #bjjj feet above the ,mare1 and a very depressed floor1 which does not appear to contain any visible detail4 ,a bright crater adjoins it on the ,s4,w41 the wall of which at the point of junction is clearly very low1 so that under oblique light the two interiors appear to communicate by a narrow pass or neck filled with shadow4 ,i have frequently seen a break in the ,n4,w4 wall of ,birt1 which seems to indicate the presence of a crater4 ,there is a noteworthy cleft on the ,e41 which can be traced from the foot of the ,e4 wall to the hills on the ,n4,e4 ,it is a fine telescopic object1 and1 under some conditions1 the wider portion of it resembles a railway cutting traversing rising ground1 seen from above4 ,it is visible as a white line under a high light4 ,,the ,,straight ,,wall4--,sometimes called the railroad1 is a remarkable and almost unique formation on the ,w4 side of ,birt1 extending for about #fe miles from ,n4,e4 to ,s4,w4 in a nearly straight line1 terminating on the south at a very peculiar mountain group1 the shape of which has been compared to a stag's horn1 but which perhaps more closely resembles a sword-handle1--the wall representing the blade4 ,when examined under suitable conditions1 the latter is seen to be slightly curved1 the ,s4 half bending to the west1 and the remainder the opposite way4 ,the formation is not a ridge1 but is clearly due to a sudden change in the level of the surface1 and thus has the outward characteristics of a fault ,along the upper edge of this gigantic cliff 7which1 though measures differ1 cannot be anywhere much less than #ejj feet high7 ,i have seen at different times many small craterlets and mounds4 ,near its ,n4 end is a large crater1 and on the ,w4 is a row of hillocks1 running at right angles to the cliff4 ,no observer should fail to examine the wall under a setting sun when the nearly perpendicular ,e4 face of the cliff is brilliantly illuminated4 ,,nicollet4--,a conspicuous little ring-plain on the ,e4 of ,birt1 and somewhat smaller4 ,between the two is a still smaller crater1 from near which runs a low mountain range1 nearly parallel to the straight wall1 to the region ,s4,e4 of the ,stag's ,horn ,mountains4 ,here will be found three small light-surrounded craters arranged in a triangle1 with a somewhat larger crater in the middle4 ,,purbach4--,an immense enclosure of irregular shape1 approximating to that of a rhomboid with slightly curved sides4 ,it is fully #fj miles across1 and the walls in places exceed #hjjj feet in altitude1 and include many depressions1 large and small4 ,on the ,e4 inner slope are some fine terraces and several craters4 ,the continuity of the circumvallation is broken on the ,n4 by a great ring-plain1 on the floor of which ,i have seen a prominent cleft and a crater near the ,s4 side4 ,there is a large bright crater in the interior of ,purbach1 ,s4 of the centre1 two others on the ,w4 half of the floor1 and a few ridges4 ,,regiomontanus4--,a still more irregular walled-plain1 of about the same area1 closely associated with the ,s4 flank of ,purbach1 having a rampart of a similar complex type1 traversed by passes1 longitudinal valleys1 and other depressions4 ,schmidt alone shows the especially fine example of a crater-row1 which is not a difficult object1 in connection with the ,s4,e4 wall4 ,excepting one crater1 nearly central1 and some inconspicuous ridges1 ,i have seen no detail on the floor4 ,schmidt1 however1 records many features4 ,,walter4--,a great rhomboidal walled-plain1 #ajj miles in diameter1 with a considerably depressed floor1 enclosed by a rampart of a very complex kind1 crowned by numerous peaks1 one of which1 on the ,w41 rises #aj1jjj feet above the interior4 ,if the formation is observed when it is close to the morning terminator1 say1 when the latter lies from l deg4 to #b deg4 ,e4 of the centre of the floor1 it is one of the most striking and beautiful objects which the lunar observer can scrutinize4 ,the inner slope of the border which abuts on ,regiomontanus1 examined at this phase under a high power1 is seen to be pitted with an inconceivable number of minute craters2 and the summit ridge1 and the region towards ,werner1 scalloped in a very extraordinary way1 the engrailing 7to use an heraldic term7 being due to the presence of a row of big depressions4 ,the floor at this phase is sufficiently illuminated to disclose some of its most noteworthy features4 ,taking its area to be about #hjjj square miles1 at least #abjj square miles of it is occupied by the central mountain group and its adjuncts1 the highest peak rising to a height of nearly #ejjj feet 7or nearly #fjj feet higher than ,ben ,nevis71 above the interior1 and throwing a fine spire of shadow thereon4 ,in the midst of this central boss are two deep craters1 one being about #aj miles in diameter1 and a number of shallower depressions4 ,in association with the loftiest peak1 ,i noted at #h h41 ,march #i1 #ahhi1 two brilliant little craters1 which presumably are not far from the summit4 ,near the ,e4 corner of the floor there is another large deep crater1 and1 ranging in a line from the centre to the ,s4,e4 wall1 three smaller craters4 ,,lexell4--,on the ,e4 of ,walter extends an immense plain of irregular outline1 which is at least equal to it in area4 ,though no large formation is found thereon2 many ridges1 short crater-rows1 and ordinary craters figure on its rugged superficies2 and on its borders stand some very noteworthy objects1 among them1 on the ,s41 the walled-plain ,lexell1 about #cb miles in diameter1 which presents many points of interest4 ,its irregular wall1 rising1 at one point on the ,s4,w41 to a height of nearly #hjjj feet1 is on the ,n4,w4 almost completely wanting1 only very faint indications of its site being traceable1 even under a low morning sun4 ,on the opposite side it is boldly terraced1 and has a large crater on its summit4 ,the interior1 the tone of which is conspicuously darker than that of the region outside1 contains a small central hill1 with two craters connected with it4 ,the low ,n4,w4 margin is traversed by a delicate valley1 which1 originating on the ,n4 side of the great plain1 crosses the ,w4 quarter of ,lexell and terminates apparently on the ,s4,w4 side of the floor4 ,,hell4--,a prominent ring-plain1 about #ah miles in diameter1 on the ,e4 side of the great plain4 ,there is a central mountain and many ridges within4 ,,ball4--,a somewhat smaller ring-plain on the ,s4,e4 edge of the great plain1 with a lofty terraced border and a central mountain more than #bjjj feet high4 ,there are two large irregular depressions on the ,w4 of the formation1 a crater on the ,s41 and a smaller one on the ,n4 wall4 ,,pitatus4--,this remarkable object1 #eh miles in diameter1 with ,hesiodus1 its companion on the ,e41 situated at the extreme ,s4 end of the ,mare ,nubium1 afford good examples of a class of formations which exhibit undoubted signs of partial destruction1 from some unknown cause1 on that side of them which faces the ,mare4 ,on every side but the ,n41 ,pitatus is a walled plain of an especially massive type1 the border on the ,s4,e4 furnishing one of the finest examples of terraces to be found on the visible surface4 ,on the ,s4,w41 two parallel rows of large crateriform depressions1 perhaps the most remarkable of their kind1 extend for #fj miles or more to the ,w4 flank of ,gauricus4 ,on the ,n4,w41 the rampart includes many curious irregular depressions and craters1 and gradually diminishes in height1 till1 for a space of about #ab miles on the ,n41 there can hardly be said to be any border at all1 its site being marked by some inconsiderable mounds and shallow hollows4 ,there is a small bright central mountain on the floor1 and1 ,s4 of it1 two larger but lower elevations4 ,a distinct straight cleft traverses the ,n4,w4 side of the interior very near the wall1 to which it forms an apparent chord1 and a second cleft occupies a similar position with respect to the bright ,n4,e4 border4 ,a narrow pass forms a communication with the interior of ,hesiodus4 ,,hesiodus4--,this walled-plain1 little more than half the diameter of the last1 has an irregular outline1 and for the most part linear walls1 which on the ,s4 are massive and lofty 7#djjj feet71 but on the ,n4 very low1 and broken by gaps4 ,there is a fine deep crater on the ,s4 border1 and a small but distinct crater on the floor1 nearly central1 the only object thereon which ,i have seen1 though ,schmidt draws a smaller one on the ,w4 of it4 ,a mountain abutting on the ,n4,e4 side of ,hesiodus is the ,w4 origin of one of the longest clefts on the moon4 ,running in an ,e4,s4,e4 direction1 it traverses the ,mare to a crater near the ,w4 face of the ,cichus mountain arm1 reappears on the ,e4 side of this object1 and is finally lost amid the hills on the ,n4 of ,capuanus4 ,the ,w4 section of this cleft is coarser and much more distinct than that lying ,e4 of the mountain arm4 ,,gauricus4--,a large walled-plain ,s4 of ,pitatus1 about #dj miles in diameter4 ,the border is very irregular1 and1 according to ,neison1 consists on the ,e4 of a precipitous cliff more than #ijjj feet high4 ,it is surrounded by a number of large rings on the ,s41 and has several considerable small depressions on its ,n4 border4 ,there is apparently no prominent detail on the floor4 ,schmidt shows some ridges and craterlets4 ,,wurzelbauer4--,another irregular walled-plain1 about #ej miles in diameter1 on the ,s4,e4 of ,pitatus1 with a very complex border1 in connection with which1 on the ,s4,w41 is a group of fine depressions1 and on the ,s4,e4 a large crater4 ,there is much detail on the very uneven floor4 ,,miller4--,one of a group of three moderately large ring-plains1 of which ,nasireddin is a member1 near the central meridian in ,s4 latitude #ci deg4 ,its massive border rises nearly #aa1jjj feet above the floor1 on which stands a central peak4 ,miller is about #cf miles in diameter4 ,,nasireddin4--,a somewhat smaller ring-plain on the ,s4 of the last1 and of a very similar type4 ,it contains a central peak and several minor elevations4 ,between its ,n4,w4 border and the ,s4,w4 flank of ,miller is a smaller ring-plain of about half the size of ,nasireddin1 and on the ,s4,e4 a large enclosure named ,,huggins4 ,,orontius4--,huggins has encroached on the ,w4 side of this irregular ring- plain and overlaps it4 ,it is of considerable size4 ,the floor includes much detail and a prominent crater4 ,,sasserides4--,a formation of irregular shape1 with very lofty walls1 situated amid the confusion of ring-plains1 craters1 crater-pits1 c41 in the region ,n4 of ,tycho1 some of which are fully as deserving of a distinct name4 ,,heinsius4--,a very curious formation on the ,n4,e4 of ,tycho3 a fine telescopic object under oblique illumination4 ,it has an irregular but continuous border1 except on the ,s41 where two large ring-plains have encroached upon it1 and a third1 ,n4 of a line joining their centres1 occupies no inconsiderable portion of the floor4 ,heinsius is nearly #ej miles across1 and the border on the ,w41 is nearly #ijjj feet above the interior1 which includes1 at least1 three small craters4 ,the walls of the intrusive ring-plains have craters on their summits2 the more westerly has two on the ,w41 and its companion1 one on the ,s4,w4 ,the ring-plain on the floor has a crater on its ,e4 wall4 ,schmidt shows a small crater between the ring-plains on the ,s4 border4 ,,saussure4--,a ring-plain ,w4 of ,tycho1 #bh miles in diameter1 with bright lofty terraced walls and a somewhat dark interior1 on which there is a crater1 ,w4 of the centre1 and some crater-pits4 ,there are several large depressions on the ,s4,w4 wall4 ,it is surrounded by formations which1 though nearly as prominent as itself1 have not1 with the exception of ,pictet on the ,e41 and one on the ,n4,w41 called ,huggins by ,schmidt1 received distinctive names4 ,the region ,w4 of ,saussure abounds in craterlets1 some of which are of the minutest type4 ,one of the ,tycho streaks is manifestly deflected from its course by this formation1 and another is faintly traceable on the floor4 ,,pictet4--,a walled-plain of irregular shape1 about #cj miles across1 between ,saussure and ,tycho1 with a border broken on the ,s4 by a large conspicuous ring-plain1 which is at least #aj miles in diameter1 and1 according to ,schmidt1 has a central mountain4 ,schmidt draws the ,s4,e4 border of ,pictet as broken by ridges extending on to the floor4 ,he also shows several craters and minor elevations thereon4 ,,tycho4--,as the centre from which the principal bright ray-system of the moon radiates1 and the most conspicuous object in the southern hemisphere1 this noble ring-plain may justly claim the pre-eminent title of the ,metropolitan crater4 ,it is more than #ed miles in diameter1 and its massive border1 everywhere traversed by terraces and variegated by depressions within and without1 is surmounted by peaks rising both on the ,e4 and ,w4 to a height of about #ag1jjj feet above the bright interior1 on which stands a magnificent central mountain at least #ejjj feet in altitude4 ,were it not somewhat foreshortened1 ,tycho would be seen to deviate considerably from what is deemed to be the normal shape4 ,on the ,s4 and ,w4 especially1 the wall approximates to the linear type1 no signs of curvature being apparent where these sections meet4 ,the crest on the ,s4 and ,s4,e4 exhibits many breaks and irregularities2 and it is through a narrow gap on the ,s4 that a rill-like valley1 originating at a small depression near the foot of the ,s4,w4 glacis1 passes1 and1 descending the inner slope of the ,s4,e4 wall obliquely1 terminates near its foot4 ,there is a distinct crater on the summit ridge on the ,s4,e41 and another below the crest on the outer ,s4,w4 slope4 ,on the ,s4 inner slope ,i have often remarked a number of bright oval objects1 which1 for the lack of a better word1 may be termed mounds though they represent masses of material many miles in length and breadth4 ,the outer slope of ,tycho1 exhibiting under a high light a grey nimbus encircling the wall1 includes--craters1 crater-pits1 shallow valleys1 spurs and buttresses--in short1 almost every variety of lunar feature is represented4 ,excepting the central mountain and a crater on the ,w4 of it1 ,i have not seen any object on the floor1 which1 for some unexplained reason1 is never very distinct4 ,schmidt shows several low ridges on the ,n4,e4 side4 ,in a paper recently published in the ,astronomische ,nachrichten1 ,professor ,w4,h4 ,pickering1 describing his observations of the ,tycho streaks made at ,arequipa1 ,peru1 with a #ac inch achromatic1 asserts that they do not radiate from the centre of ,tycho1 but from a multitude of minute craters on its ,s4,e4 or ,n4 rim4 7,see ,introduction47 ,,maginus4--,an immense partially ruined enclosure1 at least #ajj miles from side to side1 on the ,s4,w4 of ,tycho1 from which it is separated by a region covered with a confused mass of ring-plains and craters4 ,on almost every part of its broken border stand large ring-plains1 many of which1 if they were isolated1 or situated in a less disturbed region1 would rank as objects of importance2 but among such a multitude of features they pass unnoticed4 ,the largest of them occupies no inconsiderable part of the ,s4,e4 wall1 and is quite #cj miles in diameter1 its own border being also much broken by depressions1 as1 indeed1 are those of almost all the six or more large ring-plains which define the ,n4 limits of ,maginus4 ,the loftiest portion of what remains of a true border rises at one place to more than #ad1jjj feet4 ,on the floor1 which is traversed by some of the ,tycho rays1 there is a mountain group associated with a crater1 nearly central1 and several large rings on the ,n4 side4 ,though the formation is very difficult to detect under a high sun1 ,madler's dictum that the full moon knows no ,maginus is not strictly true4 ,,street4--,a walled-plain between ,tycho and ,maginus1 about #bh miles in diameter1 with a border of moderate height1 broken by depressions on the ,n4 ,there are some small craters and ridges within2 but the surrounding region1 with its almost endless variety of abnormally shaped formations1 is far more worthy of the observer's attention4 ,,deluc4--,the largest and most prominent member of a curious group of ring- plains on the ,s4,w4 of ,maginus4 ,it is about #bh miles in diameter1 and is encircled by a wall some #gjjj feet above the interior1 which includes a crater4 ,a large ring with a central mountain encroaches on the ,n4 wall1 and a smaller object of the same class on the ,s4 wall4 ,,clavius4--,there are few lunar observers who have not devoted more or less attention to this beautiful formation1 one of the most striking of telescopic objects4 ,however familiar we may consider ourselves to be with its features1 there is always something fresh to note and to admire as often as we examine its apparently inexhaustible details4 ,it is #adb miles from side to side1 and includes an area of at least #af1jjj square miles within its irregular circumvallation1 which is only comparatively slightly elevated above the bright plateau on the ,w41 though it stands at least #ab1jjj feet above the depressed floor4 ,at a point on the ,s4,w4 a peak rises nearly #ag1jjj feet above the interior1 while on the ,e4 the cliffs are almost as lofty4 ,there are two remarkable ring-plains1 each about #be miles in diameter1 associated1 one with the ,n41 and the other with the ,s4 wall1 the floors of both abounding in detail4 ,the latter1 however1 is the most noteworthy on account of the curious corrugations visible soon after sunrise on the outer ,n4 slope of its wall1 resembling the ribbed flanks of some of the ,java volcanoes4 ,there are five large craters on the floor of ,clavius1 following a curve convex to the ,n41 and diminishing in size from ,w4 to ,e4 ,the most westerly stands nearly midway between the two large ring-plains on the walls1 the second 7about two- thirds its area7 is associated with a complex group of hills and smaller craters4 ,both these objects have central mountains4 ,in addition to this prominent chain1 there are innumerable craters of a smaller type on the floor1 but they are more plentiful on the ,s4 half than elsewhere4 ,on the ,s4,e4 wall are three very large depressions4 ,on the broad massive ,n4,e4 border1 the bright summit ridge and the many transverse valleys running down from it to the floor1 are especially interesting features4 ,there are very clear indications of faulting on a vast scale where this broad section of the wall abuts on the ,n4 side of the formation4 ,,cysatus4--,a regular walled-plain1 apparently about #bh miles in diameter1 forming the most northerly member of a chain of formations1 of which ,newton1 ,short1 and ,moretus1 extending towards the ,s4 limb1 form a part4 ,its border rises nearly #ac1jjj feet above a floor devoid of prominent detail4 ,,gruemberger4--,a much larger and more irregular ring-plain1 nearly #dj miles from wall to wall1 on the ,e4 side of ,cysatus4 ,its ,w4 border rises nearly #ad1jjj feet above the interior1 which includes an abnormally deep crater1 the bottom of which is #bj1jjj feet below the crest of the ,w4 wall1 and several small depressions and ridges4 ,the inner ,e4 slope is finely terraced4 ,,moretus4--,a magnificent object1 #gh miles in diameter1 but foreshortened into a flat ellipse4 ,its beautifully terraced walls and magnificent central mountain1 nearly #gjjj feet high1 are very conspicuous under suitable conditions4 ,the rampart on the ,e4 is more than #ae1jjj feet above the floor1 while on the opposite side it is about #ejjj feet lower4 ,,short4--,a fine but foreshortened ring-plain of oblong shape1 squeezed in between ,moretus and ,newton4 ,it is about #cj miles in diameter1 and on the ,s4,e41 where its border and that of ,newton are in common1 it rises nearly #ag1jjj feet above the interior1 which includes1 according to ,neison1 a small central hill4 ,schmidt shows a crater on the ,n4 side of the floor4 ,,newton4--,is situated on the ,s4,e4 side of ,short1 and is the deepest walled-plain on the visible surface4 ,it is of irregular form and about #adc miles in extreme length4 ,one gigantic peak on the ,e4 rises to nearly #bd1jjj feet above the floor1 the greater part of which is always immersed in shadow1 so that neither the earth or sun can at any time be seen from it4 ,,malapert4--,a ring-plain situated far too near the limb for useful observation4 ,between it and ,newton is a number of abnormally shaped enclosures4 ,,cabeus4--,another object out of the range of satisfactory scrutiny4 ,madler considered that it is as deep as ,newton4 ,according to ,neison1 a central peak and two craters can be seen within under favourable conditions4 ,schmidt draws a long row of great depressions on the ,n4 side of it4 ,,east ,,longitude #bj deg4 ,,to #dj deg4 ,,landsberg4--,a ring-plain1 about #bh miles in diameter1 situated in ,mare ,nubium1 ,s4,e4 of ,reinhold1 which in many respects it resembles4 ,its regular massive border is everywhere continuous4 ,only a solitary crater breaks the uniformity of its crest1 that rises on the ,w4 to nearly #aj1jjj feet1 and on the ,e4 to about #gjjj feet above the floor1 which is depressed about #gjjj feet below the surrounding surface4 ,the inner slopes exhibit some fine terraces1 and on the broad ,w4 glacis is a curious winding valley1 which runs up the slope from the ,s4,w4 side to the crater just mentioned1 then1 bending downwards1 joins the plain at the foot of the ,n4 wall4 ,neither this nor the crater is shown in the maps4 ,the large compound central peak is apparently the sole object in the interior4 ,at #h h4 #be m4 on ,january #bc1 #ahhh1 when observing the progress of sunrise on this formation with a #h #a_/b inch ,calver-reflector charged with different eyepieces1 ,i noticed1 when about three-fourths of the floor was in shadow1 that the illuminated portion of it was of a dark chocolate hue1 strongly contrasting with the grey tone of the surrounding district4 ,this appearance lasted till the interior was more than half illuminated1 gradually becoming less pronounced as the sun rose higher on the ring4 ,e4 and ,s4,e4 of ,landsberg is a number of ring-plains and craters well worthy of careful examination4 ,five of the largest are surrounded by a glistening halo1 and one 7that nearest to the formation7 and another 7the largest of the group7 have each a minute crater on their ,n4 wall4 ,,euclides4--,one of the most brilliant objects on the moon2 a crater #g miles in diameter1 standing on a large bright area in the ,mare ,procellarum1 ,e4 of the ,riphaean ,mountains4 ,its ,e4 rim rises nearly #bjjj feet above the bright depressed floor2 on the ,w4 there is a bright little unrecorded crater4 ,,wichmann4--,this bright crater1 about #e miles in diameter1 stands on a light area in ,oceanus ,procellarum1 ,n4,n4,w4 of ,letronne and nearly due ,e4 of ,euclides4 ,some distance on the ,n4,e4 are the relics of what appears once to have been a large enclosure1 represented now by a few isolated mountains4 ,,herigonius4--,a ring-plain1 about #g miles in diameter1 in the ,mare ,procellarum1 ,n4,w4 of ,gassendi4 ,there is a small crater a few miles ,s4,e4 of it1 among the bright little mountains which flank this formation4 ,herigonius has a small central mountain1 which is a good test for moderate apertures4 ,,gassendi4--,one of the most beautiful telescopic objects on the moon's visible surface1 and structurally one of the most interesting and suggestive4 ,it is a walled-plain1 #ee miles in diameter1 of a distinctly polygonal type1 the ,n4,w4 and ,s4,w4 sections being practically straight1 while the intermediate ,w4 section exhibits a slightly convex curvature1 or bulging in towards the interior4 ,there is also much angularity about the ,e4 side1 which is evident at an early stage of sunrise4 ,the wall on the ,n4 is broken through and almost completely wrecked by the great ring- plain ,gassendi ,a4 ,the bright eastern section of the border is in places very lofty1 rising at one peak1 ,n4 of the well-known triangular depression upon it1 to #ijjj feet1 and at other peaks on the same side still higher4 ,it is very low on the ,s41 being only about #ejj feet above the surface4 ,the floor1 however1 on the ,n4 stands #bjjj feet above the ,mare ,humorum4 ,on the ,w4 there is a peak towering #djjj feet above the wall1 which is here about #ejjj feet above the floor1 and #hjjj feet above the ,mare ,nubium4 ,a very notable feature in connection with this formation is the little bright plain bounding it on the ,n4,w41 and separated from it by merely a narrow strip of wall4 ,this enclosure is flanked on the ,n4,e4 by ,gassendi ,a1 and on the ,s4,w4 and ,n4,w4 by a coarse winding ridge1 running from the ,w4 wall and terminating at a large irregular dusky depression4 ,gaudibert has detected a crater near the ,s4,e4 edge of this bright plain1 which includes also some oval mounds4 ,the interior of ,gassendi is without question unrivalled for the variety of its details1 and1 after ,plato1 has perhaps received more attention from observers than any other object4 ,the bright central mountain1 or rather mountains1 for it consists of a number of grouped masses crowned by peaks1 of which the loftiest is about #djjj feet1 is one of the finest on the moon4 ,it was carefully studied with a #f #a_/d inch ,cooke-achromatic by the late ,professor ,phillips1 the geologist1 who compared it to the dolomitic or trachytic mountains of the earth4 ,the buttresses and spurs which it throws out give its base a digitated outline1 easily seen under suitable illumination4 ,there are between #cj and #dj clefts in the interior1 the majority being confined to the ,s4,w4 quarter of the floor4 ,those most easily seen pertain to the group which radiates from the central mountain towards the ,s4,w4 wall4 ,they are all more or less difficult objects1 requiring exceptionally favourable weather and high powers4 ,a fine mountain range1 the ,percy ,mountains1 is connected with the ,e4 flank of ,gassendi1 extending in a ,s4,e4 direction towards ,mersenius1 and defining the ,n4,e4 side of the ,mare ,humorum4 ,,bullialdus4--,a noble object1 #ch miles in diameter1 forming with its surroundings by far the most notable formation on the surface of the ,mare ,nubium1 and one of the most characteristic ring-plains on the moon4 ,it should be observed about the time when the morning terminator lies on the ,w4 border of the ,mare ,humorum1 as at this phase the best view is obtained of the two deep parallel terrace valleys which run round the bright inner slope of the ,e4 wall1 of the crater-row against which they abut on the ,s4,e41 and of the massive ,w4 glacis1 with its spurs and depressions4 ,the ,s4 border of ,bullialdus has been manifestly modified by the presence of the great ring-plain ,a1 a deep irregular formation with linear walls1 which is connected with it by a shallow valley4 ,the rampart of ,bullialdus rises about #hjjj feet above a concave floor1 which sinks some #djjj feet below the ,mare on the ,e4 ,with the exception of the fine compound central mountain1 #cjjj feet high1 there are few details in the interior4 ,on the ,s41 is the fine ring-plain ,b1 connected with the ,s4,e4 wall near the crater-row by a well-marked valley1 and nearly due ,e4 of ,b is another1 a square-shaped enclosure1 ,c1 with a very lofty little mountain on the ,e4 side of it1 and a crater on its ,s4 wall4 ,in addition to these features1 there are many ridges and surface inequalities1 very prominent under oblique illumination4 ,,lubiniezky4--,a regular enclosure1 about #bc miles in diameter1 ,n4,e4 of ,bullialdus1 with a low attenuated border1 which is nowhere more than #ajjj feet in height4 ,it is tolerably continuous1 except on the ,s41 where there are two or three breaks4 ,its level dark interior presents no details to vary its monotony4 ,close under the ,n4,w4 wall is a small crater connected with it by a ridge1 and ,e4 of this a very rugged area1 traversed in every direction by narrow shallow valleys1 which are well worth looking at when close to the morning terminator4 ,a bright spur projects from the ,n4 wall of ,lubiniezky4 ,,kies4--,a somewhat similar formation1 ,s4 of ,bullialdus1 about #be miles in diameter1 also encircled by a border of insignificant dimensions1 attaining an altitude of #bdjj feet at only one point on the ,s4,e41 while elsewhere it is scarcely higher than that of ,lubiniezky4 ,it is clearly polygonal1 approximating to the hexagonal type4 ,on the more distinct ,s4 section a bright spur projects from it4 ,on the ,n4 its continuity is broken by a distinct little crater4 ,it is traversed by a remarkable white streak1 extending in a ,s4,w4 direction from ,bullialdus ,c 7where it is very wide71 across the interior1 to the more westerly of two craters ,s4,w4 of ,mercator4 ,another streak branches out from it near the centre of the floor1 and runs to the ,w4 wall4 ,the principal streak1 so far as the portion within ,kies is concerned1 represents a cleft4 ,on the ,mare ,e4 of ,kies is a curious circular mound1 and farther towards ,campanus two prominent little mountains4 ,on the ,n4,w4 is a large obscure ring and a wide shallow valley bordered by ridges4 ,,agatharchides4--,a very irregular complex ring-plain1 about #bh miles in diameter1 forming part of the ,n4,w4 side of the ,mare ,humorum4 ,it must be observed under many phases before one can clearly comprehend its distinctive features4 ,the wall is very deficient on the ,n41 but is represented in places by bright mountain masses4 ,the formation is flanked on the ,e4 by a double rampart1 which is at one place more than #ejjj feet in height1 with a deep intervening valley4 ,the ,s4 wall is traversed by a number of parallel valleys1 all trending towards ,hippalus4 ,these are included in a much wider and longer chasm1 which1 gradually diminishing in breadth1 extends up to the ,n4 wall of the latter4 ,,hippalus4--,a partially ruined walled-plain1 about #ch miles in diameter1 on the ,w4 side of the ,mare ,humorum1 ,s4 of ,agatharchides4 ,at least one- third of the border is wanting on the ,s4,e41 but under a low sun its site can be distinguished by a faint marking and the obvious difference in tone between the dark interior and the lighter-coloured plain4 ,the rest of the wall is bright and continuous1 except at a place on the ,w41 where what appears to be the segment of a large ring has encroached upon it4 ,there are two craters in the interior of ,hippalus1 and a row of parallel ridges1 running obliquely from the ,s4,w4 wall up to a cleft which traverses the floor from ,n4 to ,s4 ,w4 of ,hippalus stands a bright crater1 ,hippalus ,a1 with an incomplete little ring-plain adjoining it on the ,n4,w42 and ,n4,e4 of it a much larger obscure ring containing two little hills4 ,the ,hippalus rill-system is a very interesting one1 and the greater part of it can1 moreover1 be easily traced in a good #d inch achromatic4 ,it originates in the rugged region ,e4 of ,campanus1 from which five nearly parallel curved clefts extend up to the rocky barrier1 connecting the ,n4 side of this formation with the ,s4,w4 side of ,hippalus4 ,the most westerly of these furrows is interrupted by a crater on this wall1 but reappears on the ,n4 side of it1 and1 after making a detour towards the ,w4 to avoid a little mountain in its path1 runs partially round the ,e4 flank of ,hippalus ,a1 and then1 continuing its northerly course1 terminates amid the mountains ,w4 of ,agatharchides4 7,a short parallel cleft runs ,e4 of this from the little mountain to the ,e4 side of ,a47 ,the most easterly member of the system1 originating ,n4 of ,ramsden1 enters ,hippalus at the ,s4 side of the great gap in the border1 and1 after traversing the floor at the ,w4 foot of a ridge thereon1 also extends towards the mountains ,w4 of ,agatharchides4 ,between these clefts are three intermediate furrows1 one of which runs ,n4 from the ,n4 side of the encroaching ring already referred to1 on the ,w4 wall of ,hippalus4 ,,campanus4--,a ring-plain1 #cj miles in diameter1 on the rocky barrier1 extending in nearly a straight line from ,hippalus to ,cichus4 ,its terraced walls1 which rise on the ,e4 more than #fjjj feet above the floor1 are broken on the ,s4 by a narrow valley1 and on the ,e4 by a small crater4 ,a small central mountain is apparently the only object on a very dark interior4 ,,mercator4--,a more irregular ring-plain of about the same area1 adjoining ,campanus on the ,s4,w4 ,its rampart is somewhat lower1 and is partially broken on the ,n4 by two semi-rings1 and on the ,s4 by a gap4 ,the ,e4 wall extends on the ,s4 far beyond the limits of the formation1 and terminates in a brilliant mountain mass #fjjj feet in height4 ,there is a bright crater on the crest of both the ,e4 and ,w4 border4 ,on the plain ,e4 of ,mercator is a remarkable little crater standing on a light area1 and1 just under the wall1 a dusky pit connected with it by a rill-like marking4 ,these objects are of a very doubtful nature1 and should be carefully observed4 ,the floor of ,mercator is much lighter than that of ,campanus1 and appears to be devoid of detail4 ,,cichus4--,a conspicuous ring-plain1 about #bj miles in diameter1 with a prominent deep crater about #f miles across on its ,e4 rim4 ,it is situated on a curious boot-shaped plateau1 near the ,s4 end of the rocky mountain barrier associated with the last two formations4 ,its walls rise about #ijjj feet above a sunken floor1 on which there is some faint detail1 but apparently nothing deserving the distinction of a central mountain4 ,the plateau on the ,n4 is cut through by a fine broad valley1 which has obviously interfered with a large crateriform depression on its southern edge4 ,a cleft runs from a small crater ,w4 of the plateau up to this valley1 and extends beyond to the ,w4 wall of ,capuanus4 ,there is also a delicate cleft crossing the region ,s4 of ,cichus to the group of complicated formations ,s4,w4 of ,capuanus4 ,as already mentioned1 the great ,hesiodus cleft is associated with the ,cichus plateau4 ,,capuanus4--,a large ring-plain1 about #cd miles in diameter1 ,e4 of ,cichus1 with a border especially remarkable on the ,e41 where it rises more than #hjjj feet above the outside country1 and includes a large brilliant shallow crater4 ,it is broken on the ,n4,w4 by a small but noteworthy double crater2 and on the ,s4 its continuity is destroyed for many miles by a number of big circular and sub-circular depressions and prominent deep valleys1 far too numerous and complicated to describe4 ,the level dusky interior contains only a low mound on the ,s41 but is crossed by some light streaks running from ,n4 to ,s4 ,,ramsden4--,this ring-plain1 #ab miles in diameter1 derives its importance from the remarkable rill-system with which it is so closely associated4 ,its border1 about #ahjj feet on the ,w4 above the outside surface1 is slightly terraced within on the ,e41 where there is an unrecorded bright crater on the slope4 ,the two principal clefts on the ,s4 originate among the hills ,e4 of ,capuanus4 ,the more easterly begins at a crater on the ,n4 edge of these objects1 and runs ,n4 to the ,e4 side of ,ramsden2 the other originates at a larger crater1 and proceeds in a ,n4 direction up to a bright little mountain ,s4,w4 of ,ramsden2 when1 swerving to the ,n4,e41 it ends at the ,w4 wall of this formation4 ,this mountain is a centre or node from which three other more delicate branches radiate4 ,on the ,n41 three of the shortest clefts pertaining to the system are easily traceable from neighbouring mountains up to the ,n4 wall1 which they apparently partially cut through4 ,the ,e4 pair have a common origin1 but open out as they approach the border of ,ramsden4 ,,vitello4--,a very peculiar ring-plain1 #bh miles in diameter1 on the ,s4 side of the ,mare ,humorum1 remarkable for having another nearly concentric ring-plain1 of considerably less altitude within it1 and a large bright central boss1 overlooking the inner wall1 #agjj feet in height4 ,the outer wall is somewhat irregular1 and is broken by gaps and valleys on the ,s4 and ,n4,w4 ,it rises on the ,e4 about #ejjj feet above the ,mare1 but only about #bjjj above the interior1 which includes a crater on its ,n4 side1 and some low ridges4 ,,hainzel4--,this remarkable formation1 which is about #ee miles in greatest length1 but is hardly half so broad1 derives its abnormal shape from the partial coalescence of two nearly equal ring-plains1 the walls of both being very lofty1--more than #aj1jjj feet4 ,it ought to be observed under a morning sun when the floor is about half illuminated4 ,at this phase the extension of the broad bright terraced ,e4 border across a portion of the interior is very apparent1 and the true structural character of the formation clearly revealed4 ,the floor abounds in detail1 among which1 on the ,s41 are some large craters and a bright longitudinal ridge4 ,hainzel is flanked on the ,w4 and ,s4,w4 by a broad plateau1 ,w4 of which stand two ring-plains about #ae miles in diameter1 both having prominent central mountains and bright interiors4 ,,wilhelm ,i4--,a large irregular formation1 about #ej miles across1 ,s4,e4 of ,heinsius1 with walls varying very considerably in height1 rising more than #aa1jjj feet on the ,e41 but only about #gjjj feet on the opposite side4 ,the border is everywhere crowded with depressions1 large and small4 ,three ring-plains1 not less than #f miles in diameter1 stand upon the ,s4 wall1 the most westerly overlapping its shallower neighbour on the ,e41 which projects beyond the wall on to the floor4 ,the interior has a very rugged and uneven surface1 upon the ,n4 side of which are two very distinct craters1 and a short crater-row on the ,w4 of them4 ,it is traversed from ,w4 to ,e4 by three bright streaks from ,tycho1 two on the ,n4 being very prominent under a high light4 ,,longomontanus4--,a much larger walled-plain1 ,s4 of the last4 ,it is #ij miles in diameter1 with a border much broken by depressions1 especially on the ,n4,e4 ,at one peak on this side it rises to the tremendous altitude of #ac1jjj feet above the floor1 and at peaks on the ,w4 more than #ajjj feet higher4 ,there is a crowd of ring-plains on the ,n4,e4 quarter of the interior1 and some hills and craterlets in other parts of it4 ,it is also crossed by rays from ,tycho4 ,,schiller4--,a fine lozenge-shaped enclosure1 with a continuous but somewhat irregular border4 ,it is about #aab miles in extreme length1 and rather more than half this in breadth4 ,the loftiest section of the wall is on the ,w41 where it rises #ac1jjj feet above a considerably depressed interior4 ,there is a bright crater on this side and some terraces4 ,on the broad inner slope of the ,e4 border1 the summit ridge of which is especially well-marked1 there is a large shallow depression4 ,the floor contains scarcely any detail1 except some ridges on the ,n4 side and a few craterlets4 ,the great bright plain ,e4 of ,schiller and the region on the ,s4,e4 are especially worthy of scrutiny under a low morning sun4 ,,bayer4--,this object1 #bi miles in diameter1 with a terraced border rising on the ,w4 to a height of #hjjj feet above the floor1 is so closely associated with ,schiller1 that it may almost be regarded as forming part of it4 ,a long lofty mountain arm1 apparently connected with the ,w4 wall of the latter1 runs from the ,e4 side of ,bayer towards the ,n4,w4 ,there is a crater on the ,e4 side of the interior4 ,,rost4--,an oblong-shaped ring-plain1 #cj miles in diameter1 on the ,s4,w4 of ,schiller1 with moderately high walls1 and1 according to ,neison1 a shallow depression within1 nearly central4 ,i have seen a crater shown by ,schmidt on the ,e4 side of the floor4 ,a valley runs from the ,e4 side of ,rost to the ,s4 of ,schiller4 ,,weigel4--,a not very conspicuous ring-plain on the ,s4 of ,schiller1 with a crater on its ,n4,w4 rim1 and a larger ring adjoining it on the ,s4,e4 ,a prominent curved mountain arm from the ,e4 wall of ,schiller runs towards the ,n4 side of this formation4 ,,blancanus4--,a formation1 #ej miles in diameter1 on the ,s4,e4 side of ,clavius1 whose surpassing beauties tend to render the less remarkable features of this magnificent ring-plain and those of its neighbour ,scheiner less attractive than they otherwise would be4 ,the crest of its finely terraced wall1 which at one peak on the ,e4 rises to #ah1jjj feet1 is at least #ab1jjj feet above the interior4 ,krieger saw twenty craters on the floor 7#ahid1 ,sept4 #ba1 #ac;h471 most of them situated on the ,s4 quarter4 ,,scheiner4--,a still larger object1 being nearly #gj miles in diameter1 with a prominently terraced wall1 fully as lofty as that of ,blancanus4 ,there is a large crater1 nearly central1 two others on the ,n4,e4 side of the floor1 and a fourth at the inner foot of the ,e4 wall4 ,there is also a shallow ring on the ,n4,e4 slope4 ,schmidt shows1 but far too prominently1 two straight ridges crossing each other on the ,s4 side of the central crater4 ,,casatus4--,a large walled-plain1 about #ej miles in diameter1 ,s4,e4 of ,blancanus1 near the limb1 remarkable for having one of the loftiest ramparts of all known lunar objects2 it rises at one peak on the ,s4,w4 to the great height of #bb1bhe feet above the floor1 while there are other peaks nearly as high on the ,n4 and ,s4 ,the wall is broken on the ,e4 by a fine crater4 ,there is also a crater on the ,n4,w4 side of the very depressed floor1 together with some craterlets4 ,,klaproth4--,casatus partially overlaps this still larger but less massive formation on its ,s4,e4 flank4 ,the walls of ,klaproth are much lower and very irregular and broken1 especially on the ,w4 ,there are some ridges on the floor4 ,the neighbouring region is covered with unnamed objects1 large and small4 ,,east ,,longitude #dj deg4 ,,to #fj deg4 ,,flamsteed4--,a bright ring-plain1 #i miles in diameter1 in a barren region in the ,oceanus ,procellarum1 ,n4,e4 of ,wichmann4 ,it has a regular border 7broken at one place on the ,n4 by a gap1 which probably represents a crater71 rising to a height of about #adjj feet above the surrounding plain4 ,a great enclosure1 #fj miles in diameter1 lies on the ,n4 of ,flamsteed4 ,it is defined by low ridges which exhibit many breaks1 though under a high light the ring is apparently continuous4 ,within are several small craters and two considerable hills1 nearly central4 ,,hermann4--,a ring-plain1 about #aj miles in diameter1 in the ,oceanus ,procellarum1 ,w4 of ,lohrmann4 ,it is associated with a group of long ridges1 running in a meridional direction and roughly parallel to the coast-line4 ,,letronne4--,a magnificent bay or inflexion in the coast-line of the ,oceanus ,procellarum1 ,n4,n4,e4 of ,gassendi1 presenting an opening towards the ,n4 of nearly #ej miles1 and bounded on the ,s4 and ,s4,w4 by the lofty ,gassendi highlands4 ,its border on the ,w41 about #cjjj feet high1 is crowned with innumerable small depressions4 ,the interior includes four bright little mountains1 nearly central 7three of them forming a triangle71 a bright crater on the ,w4 side1 and several minor elevations and ridges4 ,on the plain ,n4 of the bay1 is a large bright crater1 from which a fine curved ridge runs to the central mountains4 ,if ,letronne is observed under oblique illumination1 the low mounds and ridges on the ,mare outside impress one with the idea that they represent the remains of a once complete ,n4 wall4 ,,billy4--,a ring-plain1 #ca miles in diameter1 ,s4,e4 of ,letronne1 with a very dark floor1 depressed about #ajjj feet below the grey surface on the ,w41 and a regular border1 rising more than #cjjj feet above it4 ,there is a narrow gap on the ,s41 and indications of a crater on the ,n4,w4 rim4 ,two small craters stand on the ,s4 half of the interior4 ,the formation is flanked on the ,s4,w4 by highlands4 ,,hansteen4--,a somewhat larger ring-plain1 with a lower and more irregular rampart1 rising on the ,w4 to nearly #cjjj feet above the floor1 which is depressed to about the same extent as that of ,billy4 ,both the inner and outer slopes are terraced on the ,e41 where the glacis is traversed by a short1 delicate1 rill-like valley4 ,there are some bright curved ridges on the floor4 ,on the ,w4 of ,billy and ,hansteen is a wide inlet of the ,oceanus ,procellarum1 bounded by the ,letronne region on the ,w41 and on the ,s4 by lofty highlands4 ,on the surface1 not far from the ,s4,w4 border of ,hansteen1 is a curious triangular-shaped mountain mass1 with a digitated outline on the ,s41 and including a small bright crater on its area4 ,between this and the ring- plain is a large but somewhat obscure depression1 ,n4 of which lies a rill-like object extending from the ,n4 point of the triangular mountain to the ,w4 wall4 ,at the bottom of a gently sloping valley between ,billy and ,hansteen is a delicate marking1 which seems to represent a cleft connecting the two formations4 ,,zupus4--,a formation about #ab miles in diameter with a dark floor1 situated in the hilly region ,n4,e4 of ,mersenius4 ,,fontana4--,a noteworthy ring-plain1 about #bj miles in diameter1 ,e4,n4,e4 of ,zupus1 with a bright border1 exhibiting a narrow gap on the ,s4 and two large contiguous craters on the ,n4,w4 ,the faint central mountain stands on a dusky interior4 ,on the ,n4 is a large peculiar depressed plain with a gently sloping wall1 within which are three short rill-like valleys and a crater4 ,,mersenius4--,with its extensive rill-system and interesting surroundings1 one of the most notable ring-plains in the third quadrant4 ,it is #da miles in diameter1 and is encircled by a fine rampart1 which on the side fronting the ,mare ,humorum rises #gjjj feet above the floor1 which is distinctly convex1 and is depressed #cjjj feet below the region on the ,e41 though it stands considerably above the level of the ,mare4 ,the prominently terraced border is tolerably regular on the ,n4,w41 but on the ,s4 and ,s4,e4 is much broken by craters and depressions1 the largest and most conspicuous interrupting the continuity of its summit-ridge on the latter side4 ,a fine crater-row traverses the central part of the interior1 nearly axially1 and a delicate cleft crosses the ,n4 half of the floor from the inner foot of the ,n4,e4 wall to a crater not far from the opposite side4 ,i detected another cleft on ,november #aa1 #ahhc1 also crossing the ,n4 side of the floor4 ,south of ,mersenius is the fine ring-plain ,mersenius d1 about #bj miles in diameter1 situated on the border of the ,mare2 and1 extending in a line from this towards ,vieta are two others 7a1 and ,cavendish d171 somewhat larger1 but otherwise similar2 the more easterly being connected with ,cavendish by a mountain arm4 ,one of the principal clefts of the system 7all of which run roughly parallel to the ,n4,e4 side of the ,mare1 and extend to the ,percy ,mountains ,e4 of ,gassendi7 crosses the floor of d1 and1 ,i believe1 partially cuts into its ,w4 wall4 ,another1 the coarsest1 abuts on a mountain arm connecting d with ,mersenius1 and1 reappearing on the ,e4 side1 runs up to the ,n4,w4 wall of the other ring- plain1 a1 and1 again reappearing on the ,e4 of this1 strikes across the rugged ground between a and ,cavendish d1 traversing its floor and border1 as does also another cleft to the ,n4 of it4 ,cavendish d includes a coarse cleft on its floor1 running from ,n4 to ,s41 which ,i have frequently glimpsed with a #d inch achromatic4 ,there are two other delicate clefts running from the ,gassendi region to the ,s4,w4 side of ,mersenius1 which are in part crater-rills4 ,,cavendish4--,a notable ring-plain1 #cb miles in diameter1 ,s4,e4 of ,mersenius1 with a prominently terraced border1 rising at one point on the ,s4 to a height of #fjjj feet above the interior1 on which are a few low ridges4 ,a large bright ring-plain 7e71 about #ab miles in diameter1 breaks the continuity of the ,s4,e4 wall1 and adjoining this1 but beyond the limits of the formation1 is another smaller ring with a central hill4 ,there is also a bright crater on the ,n4,w4 border4 ,the ,w4 glacis is very broad1 and includes two large shallow depressions4 ,an especially fine valley runs up to the ,n4 wall1 to the ,w4 side of e4 ,,vieta4--,one of the finest objects in the third quadrant2 a ring-plain #ea miles in diameter1 with broad lofty walls1 a peak on the west rising to nearly #aa1jjj feet1 and another ,n4 of it to considerably more than #ad1jjj feet above the interior4 ,it is bounded by a linear border1 approximating very closely to an hexagonal shape1 which is broken by many gaps and cross-valleys4 ,on the ,s41 the ,s4,w4 and ,s4,e4 sections of the wall do not meet1 being separated by a wide valley flanked on the ,w4 by a fine crater1 which has broken down the rampart at this place4 ,the ,n4 border is likewise intersected by valleys and by a crater-row4 ,the inner slopes are conspicuously terraced4 ,there is a very inconspicuous central mountain and several large craters on the floor1 some of them double4 ,ten have been counted on the ,n4 half of the interior4 ,on the ,s4,e4 of ,vieta are two fine overlapping ring-plains1 with a crater on the wall common to both4 ,,de ,,vico4--,a conspicuous little ring-plain1 about #i miles in diameter1 with a lofty border1 some distance ,e4 of ,mersenius4 ,,lee4--,an incomplete walled-plain1 about #bh miles in diameter1 on the ,s4 side of the ,mare ,humorum1 ,e4 of ,vitello1 from which it is separated by another partial enclosure1 with a striking valley1 not shown in the published maps1 running round its ,w4 side4 ,if viewed when its ,e4 wall is on the morning terminator1 some isolated relics of the wrecked ,n4,w4 wall of ,lee are prominent1 in the shape of a number of attenuated bright elevations separated by gaps4 ,within are three or four conspicuous hills4 ,,doppelmayer4--,under a high sun this large ring-plain1 #dj miles in diameter1 resembles a great bay open to the ,n4,w41 without a trace of detail to break the monotony of the surface on the side facing the ,mare ,humorum4 ,when1 however1 it is viewed under oblique morning illumination1 a low broad ridge is easily traceable1 extending across the opening1 indicating the site of a ruined wall4 ,there is an isolated mountain at the ,s4,w4 end of this1 which casts a fine spire of shadow across the floor at sunrise4 ,the interior contains a massive bright central mountain and several little hills4 ,the crest of the wall on the ,e4 is much broken4 ,,fourier4--,a large ring-plain1 #cj miles in diameter1 ,s4,w4 of ,vieta1 with a border rising at a peak on the ,w4 more than #ijjj feet above the floor1 ,there are two craters on the outer slope of the ,n4,w4 wall1 a prominent crater on the ,s4 wall1 and 7according to ,schmidt7 a small central crater on the floor1 which ,i have not seen4 ,in the region between ,fourier and ,vieta there are three ring-plains1 two 7the more westerly7 standing side by side1 and on the ,w41 towards the ,mare1 are two others much larger1 that nearer to ,fourier being traversed by one cleft1 and the other by two clefts1 crossing near the centre of the floor4 ,,clausius4--,a small bright ring-plain in an isolated position ,n4,w4 of ,schickard1 with a crater both on its ,n4 and ,s4 rim1 and a faint central hill4 ,,lacroix4--,a ring-plain #bj miles in diameter1 ,n4 of ,schickard4 ,it has a prominent central mountain4 ,,schickard4--,one of the largest wall-surrounded plains on the visible surface of the moon1 extending about #acd miles from ,n4 to ,s41 and about the same from ,e4 to ,w41 enclosing a nearly level area1 abounding in detail4 ,its border1 to a great extent linear1 is very irregular1 and much broken by the interposition of small ring-plains and craters1 and on the ,n4 by cross-valleys4 ,its general height is about #djjj feet1 the loftiest peak on the ,w4 wall rising to more than #ijjj feet above the floor4 ,the inner slopes of this vast rampart are very complex1 especially on the ,e41 where many terraces and depressions may be seen under suitable illumination4 ,there are three large ring-plains in the interior1 all of them ,s4 of the centre2 and at least five smaller ones near the inner foot of the ,e4 wall1 which can only be well observed when libration is favourable4 ,the two more easterly of the large ring-plains are connected by a cleft1 and there are several short clefts and crater-rows associated with the smaller ring-plains4 ,on the ,n4 side of the area is a number of minute craters4 ,the floor is diversified by two large dark markings--an oblong patch on the ,s4,w4 side1 abutting on the wall1 being the more remarkable2 and a dusky area1 occupying a great portion of the ,n4 part of the floor1 and extending up to the ,n4 border4 ,this is traversed by a light streak running from ,n4 to ,s41 which is the site of a row of minute craters4 ,,lehmann4--,a ring-plain1 about #bh miles in length1 on the ,n4 of ,schickard1 with which it is connected by a number of cross-valleys4 ,,drebbel4--,a bright ring-plain1 #ah miles in diameter1 on the ,n4,w4 of ,schickard1 with a lofty irregular border 7especially on the ,w471 exhibiting a well-marked terrace on the ,e41 a distinct gap on the ,n41 and a small crater on the ,s4,e4 rim4 ,on a dusky area between it and ,schickard stand three prominent deep craters4 ,,phocylides4--,this extraordinary walled plain1 with its neighbouring enclosures1 is structurally very remarkable and suggestive4 ,it consists of a large irregular formation1 with a lofty wall1 flanked on the ,n4 by a smaller and still more irregular enclosure 7b71 the floor of which is #aejj feet above that of ,phocylides1 the line of partition being a high cliff1 probably representing a fault1 whose shadow under a low sun is very striking4 ,phocylides is about #hj miles in maximum length1 or1 if we reckon the small enclosure b to form a part of it1 more than #abj miles4 ,the loftiest peak1 nearly #ijjj feet1 is on the ,w4 border1 near the partition wall4 ,the continuity of the rampart is broken on the ,s4 by a large crater4 ,there is a bright ring-plain on the ,w4 side of the floor1 and a few small craters4 ,phocylides b has only a solitary crater within it4 ,phocylides ,c1 abutting on the ,w4 flank of ,phocylides1 is about #bf miles in diameter4 ,its somewhat dusky interior is devoid of detail1 but the outer slope of its ,w4 wall is crowded with a number of minute craters1 which1 under good conditions1 may be utilised as tests of the defining power of the telescope used4 ,phocylides ,a1 on the bright ,s4,w4 plain1 is a large deep crater with a fine crater-row flanking it on the ,w4 ,,wargentin4--,a most remarkable member of the ,phocylides group1 flanking the ,s4,e4 side of ,schickard4 ,unlike the majority of lunar formations1 its floor is raised considerably above the surrounding region1 so that it resembles a shallow oval dish turned upside down4 ,it is #ed miles in diameter1 and1 except on the ,s4,w4 7where it abuts on ,phocylides b1 and for some distance is bounded by its wall71 it has only a border of very moderate dimensions4 ,on the ,n4,e4 slope of this ghostly rampart ,i have seen a distinct little crater1 and two much larger depressions on the ,n4,w4 slope4 ,there are some low ridges on the floor1 radiating from a nearly central point1 which have been aptly compared to a bird's foot4 ,,segner4--,a fine ring-plain1 #df miles in diameter1 on the ,s4,e4 side of ,schiller1 with a linear border on every side except the ,n4 ,at a peak on the ,w41 whose shadow is very remarkable1 it rises to a height of more than #hjjj feet above the outer surface4 ,there is a crater on the ,s4,w4 wall1 another on the ,n4,w4 wall1 and several depressions on the outer slope on this side4 ,the central mountain is small but conspicuous4 ,a large unnamed enclosure extends ,n4 of ,segner3 it is larger than ,schiller1 and is surrounded by a lofty barrier4 ,the bright plain between this and the latter is worth examination under a low sun4 ,,zuchius4--,is situated on the ,s4,e4 of ,segner1 which it slightly overlaps4 ,it is very similar in size and general character1 and has a lofty terraced wall1 rising at one place on the ,w4 to nearly #aa1jjj feet above the floor4 ,a very fine chain of craters1 well seen when the opposite border is on the morning terminator1 runs round the outer ,w4 slope of the wall4 ,there is a bright crater beyond this on the ,s4,w4 ,zuchius has a central peak4 ,,bettinus4--,another ring-plain of the same type and size1 some distance ,s4 of the last1 with a massive border1 terraced within1 and rising on the ,w4 more than #ac1jjj feet above the floor1 on which stands a grand central mountain1 whose brilliant summit is in sunlight a long time before a ray reaches any part of the deep interior4 ,,kircher4--,a ring-plain1 about #de miles in diameter1 ,s4 of ,bettinus1 remarkable also for its very lofty rampart1 which on the ,s4 attains the tremendous height of nearly #ah1jjj feet above the floor1 which appears to be devoid of detail4 ,,wilson4--,the most southerly of the chain of five massive ring-plains1 extending in an almost unbroken line from ,segner and differing only very slightly in size4 ,it is about #dj miles in diameter1 and has a somewhat irregular border1 both as regards shape and height1 rising at one peak on the ,s4,w4 to nearly #ad1jjj feet above a level interior1 which apparently contains no conspicuous features4 ,,east ,,longitude #fj deg4 ,,to #ij deg4 ,,grimaldi4--,this ranks among the largest wall-surrounded plains on the moon1 and is perhaps the darkest4 ,it extends #adh miles from ,n4 to ,s4 and #abi miles from ,e4 to ,w41 enclosing an area of some #ad1jjj square miles1 or nearly double that of the principality of ,wales4 ,this vast dusky surface is bounded on the ,e4 by a tolerably regular border1 having an average height of about #djjj feet1 while on the opposite side it is much broken1 and in places considerably loftier1 rising at one peak on the ,s4,w4 to an altitude of #ijjj feet4 ,about midway1 also1 this western rampart attains a great height1 as may be seen by any one who observes at sunrise the magnificent shadow of it1 and its many peaks thrown across the bluish-grey interior4 ,on the ,s4 the wall is broken by a large irregular depression1 on the ,w4 of which is a very curious ,v-shaped rill valley4 ,on the ,n4,w4 it is comparatively low1 and in places discontinuous2 and even to a greater extent than on the ,s4,w41 intersected by passes4 ,at the extreme ,n4 end1 a number of wide valleys cut through the wall and trend towards ,lohrmann4 ,there is a considerable ring-plain at the inner foot of the ,n4,e4 wall1 but1 except this and a few longitudinal ridges1 just visible under a very low sun1 there is apparently no other object to vary the monotony of this great expanse4 ,,damoiseau4--,consists of a complex arrangement of rings1 an enclosure #bc miles in diameter1 with a somewhat smaller enclosure placed excentrically within it 7the ,n4 side of both abutting on a bright plateau71 with two large depressions intervening between their ,w4 borders4 ,this peculiarity1 almost unique1 renders the formation an especially interesting object4 ,damoiseau is situated on the ,w4 side of ,grimaldi1 on the ,e4 coast-line of the ,oceanus ,procellarum1 from which the ,s4,w4 border rises at a gentle inclination4 ,on the ,n4,w4 there is a curious curved inflexion of the ,mare1 bounded by a bright cliff1 representing probably the ,e4 side of a destroyed ring1 a supposition which is strengthened by the existence of a faint scar on the surface of the sea1 extending in a curve from one extremity of the bay to the other1 and thus indicating the position of the remainder of the ring4 ,a conspicuous little crater stands at the ,s4 end of it1 and two others some distance to the ,w4 ,the smaller component of ,damoiseau contains a low central ridge4 ,,riccioli4--,an immense enclosure1 near the limb1 ,n4,e4 of ,grimaldi1 bounded by a rampart which is very irregular both in form and height1 though nowhere of great altitude1 and much broken by narrow gaps4 ,it is especially low and attenuated on the ,n41 where a number of ridges with intervening valleys traverse it4 ,on the ,s4 also a wide valley cuts through it4 ,with the exception of a few low rounded hills and ridges1 a short crater-row under the ,s4,e4 wall1 and two small craters on the ,s4,w41 there are no details on the floor1 which1 however1 is otherwise remarkable for the dusky tone of its surface1 especially on the ,n4 ,this dark patch occupies the whole of the ,n4,e4 side of the interior1 and is bounded on the ,s4 by an irregular outline1 extending at one point nearly to the centre1 and on the ,w4 by a curved edge4 ,the ,w4 side is much darker than the rest4 ,it is1 in fact1 as dark1 if not darker1 than any part of the floor of ,grimaldi4 ,riccioli extends #ajf miles from ,n4 to ,s41 and is nearly as broad4 ,it includes an area of #ijjj square miles4 ,,rocca4--,an irregular formation1 #fj miles in length1 near the limb ,s4,e4 of ,grimaldi1 consisting of a depression partially enclosed by mountain arms4 ,,sirsalis4--,the more westerly of a conspicuous pair of ring-plains about #bj miles in diameter1 in the disturbed mountain region some distance ,s4,w4 of ,grimaldi4 ,it has lofty bright walls1 rising to a great height above a depressed floor1 on which there is a prominent central mountain4 ,the ,e4 border encroaches considerably on the somewhat larger companion1 which is1 however1 scarcely a third so deep4 ,one of the longest clefts on the visible surface runs immediately ,w4 of this formation4 ,commencing at a minute crater on the ,n4 of it1 it grazes the foot of the ,w4 glacis2 then1 passing a pair of small overlapping craters 7resembling ,sirsalis and its companion in miniature71 it runs through a very rugged country to a ring-plain ,e4 of ,de ,vico 7,de ,vico a71 which it traverses1 and1 still following a southerly course1 extends towards ,byrgius1 in the neighbourhood of which it is apparently lost at a ridge1 though ,schmidt and ,gaudibert have traced it still farther in the same direction4 ,it is at least #cjj miles in length1 and varies much in width and character1 consisting in places of distinct crater-rows4 ,,cruger4--,a regular ring-plain ,e4 of ,fontana1 #cj miles in diameter1 with a dark floor1 without detail1 and comparatively low bright walls4 ,there is a smaller but very conspicuous ring-plain 7,cruger a7 on the ,w4 of it1 to which runs a branch of the great ,sirsalis cleft4 ,,eichstadt4--,a ring-plain1 #cb miles in diameter1 near the ,e4 limb1 ,s4 of ,rocca4 ,it is the largest and most southerly of three nearly circular enclosures1 without central mountains or any other details of interest4 ,on the ,w4 lies a great walled-plain with a very irregular border1 containing several ring-plains and craters1 and a crater-rill4 ,schmidt has named this formation ,,darwin4 ,,byrgius4--,a very irregular enclosure1 about #dj miles in diameter1 between ,cavendish and the ,e4 limb1 with a lofty and discontinuous border1 rising at one point on the ,e4 to a height of #gjjj feet above the floor4 ,there are wide openings both in the ,n4 and ,s4 wall1 and some ridges within4 ,the border is broken on the ,e4 by a crater1 and on the ,w4 by the well-known crater ,byrgius ,a1 from which a number of bright streaks radiate1 mostly towards the ,e4 ,one on the ,w4 extends to ,cavendish1 and another to ,mersenius1 traversing the ring-plain ,cavendish ,c4 ,north-east of ,byrgius there is a mountain arm which includes a peak #ac1jjj feet in height4 ,,piazzi4--,a walled-plain1 about #ij miles in length1 some distance ,s4,e4 of ,vieta1 with a complex broken border1 including several depressions on the ,n4,w41 rising to about #gjjj feet above a rather dark interior1 on which there is a prominent central mountain4 ,,lagrange4--,a larger but similar formation1 #ajj miles in diameter1 associated with the last on the ,n4,e41 with a complex terraced border1 including peaks of #ijjj feet1 a bright crater on the ,w41 and a ring-plain on the ,n4,w4 ,the inner slope of the ,e4 wall is a fine object at sunrise1 when libration is favourable4 ,the floor is dark and devoid of detail4 ,,bouvard4--,a great irregular enclosure1 which appears to be still larger than ,lagrange1 ,s4,e4 of ,piazzi1 and close to the limb4 ,it is bounded by a very lofty rampart1 rising at a peak on the ,w4 to #aj1jjj feet4 ,it has a fine central mountain4 ,,inghirami4--,a very remarkable ring-plain1 #fj miles in diameter1 ,e4 of ,schickard1 with a bright1 broad1 and nearly continuous border1 terraced within1 and intersected on the ,n4,e4 by narrow valleys1 one of which is prolonged over the floor and extends to the central mountain4 ,there are two curious dark spots on the ,n4 side of the interior4 ,beyond the foot of the glacis on the ,s4 a distinct cleft runs from a dusky spot to a group of small craters ,e4 of ,wargentin4 ,there is a fine regular ring-plain with a small central mount ,w4 of ,inghirami4 ,,pingre4--,a ring-plain1 about #ah miles in diameter1 between ,phocylides and the limb4 ,,hausen4--,a ring-plain1 close to the limb1 ,n4 of ,bailly1 which1 but for its position1 would be a fine object4 ,it is1 however1 never sufficiently well placed for observation4 ,,bailly4--,one of the largest wall-surrounded plains on the moon1 almost a sea in miniature1 extending #aej miles from ,n4 to ,s41 and fully as much from ,w4 to ,e4 ,when caught at a favourable phase1 it is1 despite its position1 especially worthy of scrutiny4 ,the rampart on the ,w41 of the linear type1 is broken by several bright craters4 ,on the ,s4,w4 two considerable overlapping ring-plains interfere with its continuity4 ,on the ,s4,e4 several very remarkable parallel curved valleys traverse the border4 ,the ,e4 wall1 which at one point attains a height of nearly #ae1jjj feet1 is beautifully terraced4 ,the floor on the eastern side includes several ring-plains 7some of which are of a very abnormal type71 many ridges1 and two delicate dark lines1 crossing each other near the ,s4 end1 probably representing clefts4 ,,legentil4--,a large walled-plain1 close to the limb1 ,s4 of ,bailly4 ,,fourth ,,quadrant ,,west ,,longitude #ij deg4 ,,to #fj deg4 ,,kastner4--,a large walled-plain at the ,s4 end of the ,mare ,smythii1 too near the limb for satisfactory observation4 ,,maclaurin4--,the principal member of a group of irregular ring-plains on the ,w4 side of the ,mare ,foecunditatis1 a little ,s4 of the lunar equator4 ,schmidt shows no details within it1 except a small crater on the ,e4 side of the floor4 ,,webb4--,a ring-plain ,e4 of ,maclaurin1 about #ad miles in diameter1 with a dusky floor1 enclosed by a bright rim1 on the ,n4,e4 side of which there is a small crater4 ,schmidt seems to have overlooked the central hill4 ,,langrenus4--,this noble circumvallation1 the most northerly of the meridional chain of immense walled-plains1 extending for more than #fjj miles from near the equator to ,s4 lat4 #dj deg41 would1 but for its propinquity to the limb1 rank with ,copernicus 7which in many respects it resembles7 among the most striking objects on the surface of the moon4 ,its length is about #ij miles from ,n4 to ,s41 and its breadth fully as much4 ,in shape it approximates very closely to that of a foreshortened regular hexagon4 ,the walls1 which at one point on the ,e4 rise to an altitude of nearly #aj1jjj feet1 are continuous1 except on this side1 where they are broken by the interference of an irregular depression1 and on the extreme ,s41 where they are intersected by cross-valleys4 ,within1 the terraces are remarkably distinct1 and the intervening valleys strongly marked4 ,the brilliant compound central mountain rises at its loftiest peak to a height of more than #cjjj feet4 ,on the ,n4 of it is an obscure circular ring1 which may possibly merely represent a fortuitous combination of ridges1 though it has all the appearance of a modified ring-plain4 ,on the ,mare1 some distance ,n4,e4 of the formation1 is a group of three ring-plains1 with two small craters 7associated with a ridge7 on the ,n4 of them4 ,two of the more westerly of these objects have prominent central mountains1 and the third a very dark interior4 ,at least three bright streaks originate on the ,e4 flank of ,langrenus1 which1 diverging widely1 traverse the ,mare ,foecunditatis4 ,,flattenings ,,on ,,the ,,moon',s ,,western ,,limb4--,about thirty years ago1 the ,rev4 ,henry ,cooper ,key drew attention to certain flattenings which he had noted on the ,w4 limb1 which are very apparent under favourable conditions of libration4 ,their position cannot be closely defined1 but the principal deviation from circularity extends from about ,s4 lat4 #aj deg4 to the region on the limb opposite the ,s4 border of the ,mare ,crisium4 ,,vendelinus4--,the second great enclosure pertaining to the meridional chain--a magnificent walled-plain of about the same dimensions as the last4 ,it is bounded by a very irregular rampart1 which1 under evening illumination1 is especially noteworthy1 though nowhere approaching the altitude of that of ,langrenus4 ,its continuity on the ,w4 is broken by the great ring-plain ,vendelinus ,c1 about #ej miles in diameter1 a formation resembling ,langrenus in miniature4 ,this is hexagonal in shape1 and has many rings and depressions on its ,w4 wall4 ,south of ,vendelinus ,c1 the wall of ,vendelinus runs up in a bold curve to the fine terraced ring- plain ,vendelinus ,b1 and is surmounted by a bright serpentine crest1 and traversed by several valleys running down the slope to the floor4 ,b has a small crater on its ,n4 wall1 and another in the interior4 ,there is a wide gap in the ,s4 border of ,vendelinus1 which is partially occupied by another somewhat smaller ring-plain1 bounded by a southerly extension of the ,e4 wall1 which includes on its outer slope many craters and other depressions1 and abuts near its ,n4 end on the large ring-plain ,vendelinus ,a1 which has a prominently terraced wall and a large bright central mountain4 ,between ,a and ,c extends a plateau that may be regarded as the ,n4 limit of the formation1 including1 among other minor details1 a fine cleft1 which traverses it from ,n4 to ,s41 and ultimately extends to a group of craters on the floor4 ,on the ,s4 side of the interior is one large ring-plain1 flanked on the ,w4 by two small craters4 ,near the ,n4 end are many bright little craters1 many of them unrecorded4 ,vendelinus ,c is bordered on the ,e4 by two large semicircular formations with low walls extending on to the floor4 ,mr4 ,w4,h4 ,maw and others have detected many minute depressions in connection with these curious objects2 and ,n4 of them1 on the outer slope of ,c1 where it runs out to the level of the plateau1 ,i have seen the surface at sunset riddled like a sieve with craterlets and little pits4 ,there is an irregular ring-plain ,n4 of ,a1 with linear walls1 and another1 much smaller and brighter1 on the ,n4 of this1 standing a little beyond the ,n4 limits of ,langrenus4 ,,la ,,peyrouse4--,a much foreshortened walled-plain1 #da miles in diameter1 close to the limb1 ,s4,w4 of ,langrenus4 ,there is a longitudinal ridge on the floor4 ,between it and ,langrenus are two large ring-plains with central mountains1 and on the ,n4,e41 ,la ,peyrouse ,a1 a bright crater1 adjoining which is ,la ,peyrouse ,,delta1 one of the most brilliant spots on the moon4 ,,ansgarius4--,a ring-plain1 #ej miles in diameter1 still nearer to the limb than the last4 ,,behaim4--,a great ring-plain1 #fe miles in diameter1 ,s4 of ,ansgarius1 and connected with it by ridges4 ,it has lofty walls and a central mountain4 ,,hecataeus4--,an immense walled-plain1 #aae miles in length1 on the ,s4,w4 of ,vendelinus1 with a very irregular rampart and a conspicuous central mountain4 ,it is flanked ,e4 and ,w4 by other large enclosures1 which can only be seen to advantage when libration is favourable4 ,w4 ,,humboldt4--,though close to the limb1 this enormous wall-surrounded plain1 some #acj miles in extreme length1 and estimated to have an area of #ab1jjj square miles1 is well worth observing under suitable conditions4 ,it ranks among the largest formations of its class1 and in many respects resembles ,bailly on the ,s4,e4 limb4 ,at one point on the ,e4 a peak rises to #af1jjj feet1 and on the opposite side there are peaks nearly as high4 ,the floor contains some detail--a crater1 nearly central1 associated with ridges1 and two dark spots1 one at the ,s4 and the other at the ,n4 end4 ,,phillips4--,abuts on the ,e4 side of ,w4 ,humboldt4 ,it is a walled-plain1 about #hj miles in length1 with a border much broken on the ,e41 and terraced within on the opposite side4 ,there are many hills and ridges on the floor4 ,,legendre4--,a fine ring-plain1 #df miles in diameter1 on the ,s4,e4 of the last4 ,according to ,schmidt1 there is a crater on the ,s4 side of the floor4 ,there is a small ring-plain1 ,,adams1 on the ,s4 ,,petavius4--,the third member of the great meridional chain3 a noble walled-plain1 with a complex rampart1 extending nearly #ajj miles from ,n4 to ,s41 which encloses a very rugged convex floor1 traversed by many shallow valleys1 and includes a massive central mountain and one of the most remarkable clefts on the visible surface4 ,to observe these features to the best advantage1 the formation should be viewed when its ,w4 wall is on the evening terminator4 ,at this phase a considerable portion of the interior on the ,n4 is obscured by the shadow of the rampart1 but the principal features on the ,s4 half of the floor1 and on the broad gently- shelving slope of the ,w4 wall1 are seen better than under any other conditions4 ,the border is loftiest on the ,e41 where the ring-plain ,wrottesley abuts on it4 ,it rises at this point to nearly #aa1jjj feet1 while on the opposite side it nowhere greatly exceeds #fjjj feet above the interior4 ,the terraces1 however1 on the ,w4 are much more numerous1 and1 with the associated valleys1 render this section of the wall one of the most striking objects of its class4 ,the ,n4 border is conspicuously broken by the many valleys from the region ,s4 of ,vendelinus1 which run up to and traverse it4 ,on the ,s41 also1 it is intersected by gaps1 and in one place interrupted by a large crater4 ,there is a remarkable bifurcation of the border ,s4 of ,wrottesley4 ,a lower section separates from the main rampart and1 extending to a considerable distance ,s4,e4 of it1 encloses a wide and comparatively level area which is crossed by two short clefts4 ,the central mountains of ,petavius1 rising at one peak to a height of nearly #fjjj feet above the floor1 form a noble group1 exceeding in height those in ,gassendi by more than #bjjj feet4 ,the convexity of the interior is such that the centre of it is about #hjj feet higher than the margin1 under the walls2 a protuberance which would1 nevertheless1 be scarcely remarked in situ1 as it represents no steeper gradient than about #a in #cjj on any portion of its superficies4 ,the great cleft1 extending from the central mountains to the ,s4,e4 wall1 and perhaps beyond1 was discovered by ,schroter on ,september #af1 #aghh1 and can be seen in a #b inch achromatic4 ,in larger instruments it is found to be in places bordered by raised banks4 ,,wrottesley4--,a formation1 about #be miles in diameter1 closely associated with the ,e4 wall of ,petavius1 the shape of which it has clearly modified4 ,its border on the ,e41 of the linear type1 rises nearly #ijjj feet above a light interior1 where there is a small bright central mountain and some mounds4 ,there is a prominent valley running along the inner slope of the ,w4 wall4 ,,palitzsch4--,if this extraordinary formation is observed when the moon is about three days old1 it resembles a great trough1 or deep elongated gorge flanking the ,w4 wall of ,petavius1 though it is a true ring-plain1 albeit of a very abnormal type1 about #fj miles in length and #bj miles in breadth1 with a somewhat dusky interior4 ,on the outer slope of its ,w4 wall is a bright ring-plain with a lofty border and a central mountain4 ,,hase4--,an irregular formation1 about #ej miles in diameter1 on the ,s4,w4 of ,petavius1 with which it is connected by extensions of the ,w4 and ,e4 walls of the latter4 ,its rampart1 some #gjjj feet above the floor1 is broken by depressions on the ,w42 and on the ,s4 is bounded by a smaller ring-plain with still loftier walls4 ,schmidt shows a large crater and three smaller ones on the ,w4 side of the floor4 ,,marinus4--,a ring-plain on the ,n4,e4 side of the ,mare ,australe1 between ,furnerius and the limb4 ,,furnerius4--,the fourth and most southerly component of the great meridional chain of walled-plains1 commencing on the ,n4 with ,langrenus3 a fine but irregular enclosure1 about #hj miles in extreme length and much more in breadth4 ,its rampart is very lofty1 and tolerably continuous on the ,n4 and ,w41 but on the other sides is interrupted by small craters and depressions4 ,at peaks on the ,e4 it attains a height of more than #aa1jjj feet above the interior1 and there are other peaks rising nearly as high4 ,there is a ring-plain 7,furnerius ,b7 with a central hill1 on the ,e4 side of the floor1 and numerous craters and crater-pits in other parts of it4 ,on the ,n4,w4 side of ,b there is a short cleft1 on the ,w41 a well-marked crater-row1 and on the ,e4 a long rill-valley4 ,the very brilliant crater 7,furnerius ,a7 on the ,n4,e4 glacis is the origin of two fine light streaks1 one extending ,s4 for more than #ajj miles1 and the other in the opposite direction for a great distance4 ,,fraunhofer4--,a ring-plain1 ,s4 of ,furnerius1 about #cj miles in diameter1 with a regular border rising about #ejjj feet above the floor4 ,a smaller ring-plain abuts on the ,n4,e4 side of it1 which has slightly disturbed its wall4 ,,oken4--,a large enclosure in ,s4 lat4 #dc deg4 with broken irregular walls4 ,it is too near the limb for observation4 ,,vega4--,schmidt represents this peculiar formation1 situated ,s4,e4 of ,oken1 as having a regular curved unbroken rampart on the ,e41 while the opposite border is occupied by four large partially overlapping ring-plains1 two of which contain small craters4 ,the floor is devoid of detail4 ,,pontecoulant4--,a great irregular walled plain1 about #ajj miles in length1 near the ,s4,w4 limb1 with a border rising in places to a height of #fjjj feet above the floor4 ,,hanno4--,a smaller and more regular enclosure1 adjoining ,pontecoulant on the ,n4,w41 and still nearer the limb4 ,,west ,,longitude #fj deg4 ,,to #dj deg4 ,,messier4--,the more westerly of a remarkable pair of bright craters1 about #i miles in diameter1 standing in an isolated position in the ,mare ,foecunditatis just ,s4 of the ,equator4 ,madler represents them as similar in every respect1 but ,webb1 observing them in #ahee and #ahef with a #c #g_/aj achromatic1 found them very distinctly different1--,messier1 the more westerly1 being not only clearly smaller than its companion1 but longer from ,w4 to ,e4 than from ,n4 to ,s41 as it undoubtedly is at the present time4 ,messier ,a1 however1 as the companion is termed1 though larger1 is certainly not circular1 as sometimes shown1 but triangular with curved sides4 ,it is just possible that change may have occurred here1 for ,madler carefully observed these objects more than three hundred times1 and1 it may be presumed1 under very different phases4 ,messier ,a is the origin of two slightly divergent light streaks1 resembling a comet's tail1 which extend over the ,mare towards its ,e4 border ,n4 of ,lubbock1 and are crossed obliquely by a narrower streak4 ,messier and ,messier ,a stand near the ,s4 and narrowest end of a tapering curved light area4 ,there is a number of craterlets and minute pits in the neighbourhood1 and under a high light two round dusky spots are traceable in connection with the comet marking1 one just beyond its northern1 and the other beyond its southern border1 near its ,e4 extremity4 ,,lubbock4--,a brilliant little crater1 about #d or #e miles in diameter1 near the ,e4 coast-line of the ,mare ,foecunditatis4 ,the region ,e4 of this object is particularly well worthy of scrutiny under a low sun1 on account of the variety of detail it includes4 ,on the ,s4,e4 run three fine parallel clefts1 originating near the ,n4 end of the ,pyrenees4 ,,guttemberg4--,a very fine ring-plain of peculiar shape1 about #de miles in width1 with a lofty wall1 broken on the ,n4,w4 by another ring-plain some #ad miles in diameter1 and on the ,s4,e4 by a small but distinct crater4 ,the border presents a wide opening towards the ,s41 which is traversed by a number of longitudinal valleys1 both the ,e4 and ,w4 sections of the wall being prolonged in this direction4 ,a fine crater-row runs round the outer slope of the ,e4 wall1 from the crater just mentioned to the ,n4 side of the formation4 ,it is best seen when the ,w4 wall is on the evening terminator4 ,there is also a broad valley on the ,s4 prolongation of the ,w4 wall4 ,the central mountain is bright but not large4 ,a cleft crosses the ,n4,w4 side of the floor4 ,north of ,guttemberg there is a curious oblong formation with low walls1 connected with the ,n4,e4 border by a ridge1 and with the ,n4 border by a remarkable row of depressions1 situated on a mound2 and beyond this object on the ,e4 are three parallel clefts running towards the ,n4,e4 ,on the ,w4 will be found some of the clefts belonging to the ,goclenius rill-system4 ,in the rugged region ,s4,e4 of the formation is a peculiar low ring with a very uneven floor and a large central hill4 ,the ,e4 wall of ,guttemberg may be regarded as forming a portion of the ,pyrenees ,mountains4 ,,goclenius4--,a ring-plain1 about #bh miles in diameter1 bearing much resemblance to ,plinius in form and size1 and1 like this formation1 associated with a fine system of clefts4 ,the lofty rampart1 tolerably continuous on the ,w41 is broken on the ,s4,w4 by a bright crater1 and on the ,n4,w4 by a remarkable triangular depression4 ,it is also traversed by a delicate valley extending from the crater on the ,s4,w4 to another on the ,n4,w4 border2 and at a point a little ,w4 of the first crater is dislocated by an intrusive mass of rock4 ,there are several gaps on the ,e4 and many spurs and irregularities in outline both within and without4 ,a great portion of the ,n4 wall is linear1 and joins the ,e4 section nearly at right angles4 ,west of the triangular depression it appears to be partially wrecked1 indications of the destruction being very evident if it be observed when the ,e4 wall is near the morning terminator4 ,the small bright central mountain is remarkable for its curious oblong shadow4 ,two clefts traverse the interior of ,goclenius4 7#a7 ,originates at the ,s4 wall1 ,e4 of the crater1 and runs ,e4 of the central mountain to the ,n4 wall2 7#b7 crosses the debris of the ruined ,n4,w4 border1 runs parallel to the first1 and extends nearly to the centre of the floor1 7#a7 ,re-appears at the foot of a mound outside the ,n4 wall1 and1 after crossing the outer ,w4 slope of the great ring-plain on the ,n4,w4 wall of ,guttemberg1 runs to the ,w4 side of an oblong formation ,n4 of it4 ,there are two other clefts1 closely parallel and ,w4 of this1 traversing the ,mare1 and terminating among the mountains on the ,n4,w4 ,these are crossed at right angles by what appears to be a fault1 running in a ,n4,w4 direction from the ,w4 side of ,guttemberg4 ,,macclure4--,one of a curious group of formations situated in the ,mare ,foecunditatis some distance ,s4,w4 of ,goclenius4 ,it is a bright ring-plain1 about #ae miles in diameter1 with a narrow gap in the ,n4,e4 wall and a small central hill4 ,a prominent ridge runs up to the ,n4 border2 and on the ,s4,w4 a rill-valley may be traced1 extending ,s4 to a bright deep little crater ,w4 of ,cook4 ,,crozier4--,a conspicuous ring-plain a few miles ,n4,n4,w4 of ,mac,clure1 and of about the same size4 ,it has a faint central hill4 ,neison refers to two long straight streaks extending from ,crozier towards ,messier4 ,,bellot4--,a brilliant little ring-plain ,n4,e4 of ,crozier4 ,,cook4--,a ring-plain1 about #be miles in diameter1 on the ,e4 side of the ,mare ,foecunditatis in ,s4 lat4 #ag deg41 with low and 7except on the ,s4,e47 very narrow walls4 ,there is a small circular depression on the ,s4 border1 and a prominent crater on the ,w4 side of the dark interior4 ,on the ,s4,s4,e4 is the curiously shaped enclosure ,cook d1 with very bright broad lofty walls and a fine central mountain4 ,on the plain ,w4 of ,cook is a conspicuous crater-row1 consisting of six or seven craters1 diminishing in size in both directions from the centre4 ,,colombo4--,a fine ring-plain1 about #ej miles in diameter1 situated in the highlands separating the ,mare ,foecunditatis and the ,mare ,nectaris4 ,the wall1 rising at one place to a height of #hjjj feet above the floor1 is very complicated and irregular1 being traversed within by many terraces1 and almost everywhere by cross-valleys4 ,its shape is greatly distorted by the large ring-plain a1 which abuts on its ,n4,e4 flank4 ,it loses its individuality altogether on the ,s41 its place being occupied by two large depressions1 and lofty mountains trending towards the ,s4,e4 ,in the centre there are several distinct bright elevations4 ,,magelhaens4--,the more northerly and the larger of a pair of ring-plains between ,colombo and ,goclenius1 with a bright and somewhat irregular though continuous border4 ,the dark interior includes a small central mountain4 ,its companion on the ,s4,w41 ,magelhaens a1 slightly overlaps it4 ,this also has a central hill1 and a crater on the outer slope of its ,e4 wall4 ,,santbech4--,a very prominent ring-plain1 #df miles in diameter1 on the ,s4,e4 side of the ,mare ,foecunditatis1 ,w4 of ,fracastorius4 ,the continuity of its fine lofty rampart is broken on the ,w41 where it rises nearly #aj1jjj feet above the floor1 by a brilliant little crater just below the crest1 and by a narrow gap on the ,s4 ,the wall on the ,e4 towers to a height of #ae1jjj feet above the interior4 ,on its broad outer slope1 near the summit1 there is a fine crater1 and ,s4 of this running obliquely down the slope a distinct valley4 ,on the ,n4,e41 where the glacis runs down to the level of the surrounding plain1 there is a large crateriform object with a broken ,n4 border1 and a small crater opposite the opening4 ,a long coarse valley runs from this latter object in a ,n4,e4 direction to the region ,w4 of ,bohnenberger4 ,santbech contains a prominent central peak4 ,,biot4--,a brilliant little ring-plain1 scarcely more than #g miles in diameter1 standing in an isolated position in the ,mare ,foecunditatis ,n4,e4 of ,wrottesley4 ,there is a number of bright streaks in its neighbourhood2 and a few miles ,e4 of it1 in the hilly region ,w4 of ,santbech1 another conspicuous crater of about the same size4 ,,borda4--,a ring-plain about #be miles in diameter1 ,s4,s4,w4 of ,santbech1 with a rampart low on the ,n4 and ,s41 but elsewhere of considerable height1 and a very conspicuous central mountain4 ,a wide deep valley flanked by lofty mountains extends from the ,n4 wall for many miles towards the ,n4,w4 ,it is an especially noteworthy object when the ,w4 wall of ,santbech is on the evening terminator1 as its somewhat winding course1 indicated by the bright summit-ridges of the bordering mountains1 can be followed some hours before either the interior of the valley or the region between it and ,santbech are in sunlight4 ,among the mountains ,w4 of ,borda there is a peak more than #aa1jjj feet in height4 ,,snellius4--,a very fine ring-plain1 #ej miles in diameter1 ,s4,e4 of ,petavius1 with terraced walls1 considerably broken on the ,s4,e4 by craters1 c4 ,it rises on the ,e4 nearly #gjjj feet above a dark floor1 which contains a central mountain4 ,n4,e4 of ,snellius is a smaller ring- plain 7,snellius a71 and due ,e4 a curious rough plateau1 bordered on the ,n4 and ,s4 by a number of small craters4 ,,stevinus4--,a somewhat larger ring-plain1 ,s4 of ,snellius1 with a border rising on the ,s4 to more than #aa1jjj feet above a dark interior1 which includes a bright central mountain4 ,,reichenbach4--,a very abnormally-shaped ring-plain1 about #cj miles in diameter1 with a rampart nearly #ab1jjj feet high4 ,the border is broken on the ,w41 ,s41 and ,e4 by craters and depressions1 and on the ,n4 is flanked by two overlapping ring-plains1 a and b4 ,on the ,s4,w4 lies a magnificent serpentine valley1 fully #ajj miles in length and about #ab miles in breadth at the ,n4 end1 but gradually diminishing as it runs southwards1 till it reaches a depression ,n4 of ,rheita1 where it terminates3 here is scarcely more than #d miles wide4 ,,rheita4--,a formation1 about #ce miles in diameter1 ,s4 of ,reichenbach1 with regular lofty walls1 rising at a peak on the ,n4,e4 to a height of more than #ad1jjj feet above the interior1 on which there is a small but prominent central mountain1 a smaller elevation ,w4 of the centre1 and two adjoining craters at the foot of the ,s4 wall4 ,on the ,e4 originates another fine valley1 very similar to that already mentioned in connection with ,reichenbach4 ,it runs in a ,s4,s4,w4 direction1 is about #ajj miles in length1 and1 in its widest part1 is about #ab miles across4 ,like the ,reichenbach valley1 it terminates at a small crater-like object1 which has a border broken down on the side facing the valley1 and a small central hill4 ,about midway between its extremities1 this great gorge is crossed by a wall of rock1 like a narrow bridge4 ,,janssen4--,an immense irregular enclosure1 reminding one of the very similar area1 bordered by ,walter1 ,lexell1 ,hell1 c41 in the third quadrant4 ,it extends about #aej miles from ,e4 to ,w41 and more than #ajj from ,n4 to ,s41 its limits on the ,n4 being rather indefinite4 ,its very rugged humpy surface includes one great central mountain1 and innumerable minor hills and ridges1 craters1 and crater-pits2 but the principal feature is the magnificent curved rill-valley running from the ,s4 side of ,fabricius across the rough expanse to the ,s4 side4 ,this fine object1 very coarse on the ,n41 passes the central mountain on the ,e4 side1 and becomes gradually narrower as it approaches the border2 before reaching which1 another finer cleft branches from it on the ,w41 and also runs to the ,s4 side of the plain4 ,,lockyer4--,a prominent deep ring-plain1 #cb miles in diameter1 with massive bright lofty walls1 standing just outside the ,s4,e4 border of ,janssen4 ,schmidt shows a minute crater on the ,s4 rim4 ,i have seen a crater within1 at the inner foot of the ,w4 wall1 and a central peak4 ,,fabricius4--,a ring-plain1 #ee miles in diameter1 with a lofty terraced border1 rising on the ,s4,w4 to a height of nearly #aj1jjj feet above the interior4 ,it is partially included by the rampart of ,janssen1 and the great rill-valley on the floor of the latter appears to cut through its ,s4 wall4 ,there is a long central mountain on the floor1 with a prominent ridge extending along the ,e4 side of it4 ,w4 of ,fabricius 7between it and the border of ,janssen7 lies a very irregular enclosure1 with three distinct craters within it2 and on the ,e41 running from the wall to the ,e4 side of ,janssen1 is a straight narrow valley4 ,both ,fabricius and ,janssen should be viewed under a low morning sun4 ,,steinheil4--,a double ring-plain1 ,w4 of ,janssen1 #bg miles in diameter4 ,the more easterly formation sinks to a depth of nearly #ab1jjj feet below the summit of the border4 ,,metius4--,this ring-plain1 of about the same size as ,fabricius1 but with a still loftier barrier1 abuts on the ,n4 wall of this formation1 and has caused a very obvious deformation in its contour4 ,it is prominently terraced internally1 and on the ,w4 the wall rises at one peak to a height of #ac1jjj feet above the floor1 which contains a deep crater on the ,w4 of the centre1 and many ridges4 ,,biela4--,a considerable ring-plain1 about #ee miles in diameter1 ,s4,w4 of ,janssen1 with a wall broken on the ,n4,w41 ,s41 and ,e4 by rings and large enclosures4 ,there is a central mountain1 but apparently no other details on the floor4 ,,rosenberger4--,this formation1 about #ej miles in diameter1 is one of the remarkable group of large rings to which ,vlacq1 ,hommel1 ,pitiscus1 c41 belong4 ,its walls1 though of only moderate altitude1 are distinctly terraced4 ,in addition to a prominent central mountain 7,e4 of which ,schmidt shows two craters71 there is a large crater on the ,s4 side of the floor1 and many smaller craters and crater-pits4 ,,hagecius4--,the most westerly member of the ,vlacq group of formations4 ,it is situated on the ,s4,w4 of ,rosenberger1 and is about #ej miles in diameter4 ,the rampart on the ,e4 is continuous and of the normal type1 but on the opposite side is broken by a number of smaller rings4 ,,west ,,longitude #dj deg4 ,,to #bj deg4 ,,censorinus4--,a brilliant little crater1 with very bright surroundings1 in the ,mare ,tranquilitatis1 nearly on the moon's equator1 in ,w4 long4 #cb deg4 #bb min4 ,another smaller but less conspicuous crater adjoins it on the ,w4 ,on the ,mare to the ,s4 extends a delicate cleft which trends towards the ,sabine and ,ritter rill system4 ,,capella4--,forms with ,isodorus1 its companion on the ,e4 7which it partially overlaps71 a very noteworthy object4 ,it is about #cj miles in diameter1 with finely terraced walls1 broken on the ,s4,w4 by broad intrusive rill-valleys4 ,the rampart on the ,n4,e4 is also cut through by a magnificent valley1 which extends for many miles beyond the limits of the formation4 ,there is a fine central mountain1 on which ,m4 ,gaudibert discovered a crater1 the existence of which has been subsequently verified by ,professor ,weinek on a ,lick observatory negative4 ,,isodorus4--,the rampart of this fine ring-plain1 which is of about the same size as ,capella1 rises at a peak on the ,w4 to a height of more than #ac1jjj feet above the interior1 which1 except a small bright crater at the foot of the ,e4 wall and a smaller one adjoining it on the ,n41 contains no detail4 ,the region between ,isodorus and the equator includes many interesting objects1 among them ,isodorus b1 an irregular formation open towards the ,n41 and containing several craters4 ,,bohnenberger4--,a ring-plain about #bb miles in diameter1 situated on the ,w4 side of the ,mare ,nectaris1 under the precipitous flanks of the ,pyrenees1 whose prominent shadows partially conceal it for many hours after sunrise4 ,the circular border is comparatively low1 and1 except on the ,n41 continuous4 ,here there is a gap1 and on the ,w4 of it an intrusive mass of rock4 ,from its very peculiar shadow at sunrise1 the wall on the ,e4 appears to be very irregular4 ,the club-shaped central mountain is of considerable size1 but not conspicuous4 ,s4 of ,bohnenberger stands the very attenuated ring1 ,bohnenberger ,a4 ,it is of about the same diameter1 has a large deep crater on its ,n4 rim1 and a smaller one1 distinguished with difficulty1 on its ,s4,e4 rim4 ,on the ,n4 of ,bohnenberger there is a bright little ring-plain connected with the formation by a lofty ridge1 under the ,e4 flank of which ,schmidt shows a crater-chain4 ,an especially fine cleft originates on the ,e4 side of this crater1 which1 following an undulating course over the ,mare ,nectaris1 terminates at ,rosse1 ,n4 of ,fracastorius4 ,,torricelli4--,a remarkable little formation in the ,mare ,tranquilitatis1 ,n4 of ,theophilus1 consisting of two unequal contiguous craters ranging from ,w4 to ,e41 whose partition wall has nearly disappeared1 so that1 under a low sun1 when the interior of both is filled with shadow1 the pair resemble the head of a javelin4 ,the larger1 western1 ring is about #aj miles in diameter1 and the other about half this size4 ,there is a gap in the ,w4 wall of the first1 and a long spur projecting from its ,s4 side2 and a minute crater on the ,s4 border of the smaller object4 ,torricelli is partially enclosed on the ,s4 by a circular arrangement of ridges4 ,there is a delicate cleft running in a meridional direction on the ,mare1 ,e4 of the formation1 and another on the ,n41 running from ,w4 to ,e4 ,,hypatia4--,a ring-plain1 about #cj miles in extreme length1 of very abnormal shape1 on the ,e4 side of the ,mare1 ,n4,n4,e4 of ,theophilus1 with a wall rising at a peak on the ,e4 to a height of more than #gjjj feet above a dusky floor1 which does not apparently contain any detail4 ,a small crater breaks the uniformity of the border on the ,w4 ,beyond the wall on the ,s4,e4 lies the fine bright crater ,hypatia ,a1 with another less prominent adjoining it on the ,s4,w4 ,,theophilus4--,the most northerly of three of the noblest ring-mountains on the visible surface of the moon1 situated on the ,n4,e4 side of the ,mare ,nectaris4 ,it is nearly #fd miles in diameter1 and is enclosed by a mighty rampart towering above the floor at one peak on the ,w4 to the height of #ah1jjj feet1 and at two other peaks on the opposite side to nearly #af1jjj and #ad1jjj4 ,the border1 though appearing nearly circular with low powers1 is seen1 under greater magnification1 to be made up of several more or less linear sections1 which give it a polygonal outline4 ,it is prominently terraced within1 the loftier terraces on the ,w4 rising nearly to the height of the crest of the wall1 and including several craters and elongated depressions4 ,on the ,w4 glacis is a row of large inosculating craters2 and near its foot1 ,s4,e4 of ,madler1 a short unrecorded rill- valley4 ,the magnificent bright central mountain is composed of many distinct masses surmounted by lofty peaks1 one of which is about #fjjj feet above the floor1 and covers an area of at least #cjj square miles4 ,except a distinct crater on the ,s4,w4 quarter1 this appears to be the only object within the ring4 ,,cyrillus4--,the massive border of ,theophilus partially overlaps the ,n4,w4 side of this great walled-plain1 which is even more complex than that of its neighbour1 and far more irregular in form1 exhibiting many linear sections4 ,its crest on the ,s4,e4 is clearly inflected towards the interior1 a peculiarity that has already been noticed in connection with ,copernicus and some other objects4 ,on the inner slope of this wall there is a large bright crater1 in connection with which have been detected two delicate rills extending to the summit4 ,i have not seen these1 but one of the crater-rows shown by ,schmidt1 between this crater and the crest1 has often been noted4 ,the ,n4,e4 wall is very remarkable4 ,it appears to be partially wrecked4 ,if observed at an early stage of sunrise1 a great number of undulating ridges and rows of hillocks will be seen crossing the region ,e4 of ,theophilus4 ,they resemble a consolidated stream of ropy lava which has flowed through and over the wall and down the glacis4 ,the arrangement of the ridges within ,cyrillus is very noteworthy1 as is also the triple mountain near the centre of the floor4 ,the fine curved cleft thereon traverses the ,w4 side1 sweeping round the central mountains1 and then turning to the south4 ,i have only occasionally seen it in its entirety4 ,there are also two oblong dark patches on the ,s4 side of the interior4 ,the ,s4 wall of ,cyrillus is broken by a narrow pass opening out into a valley situated on the plateau which bounds the ,w4 side of the oblong formation lying between it and ,catherina1 and overlooking a curious shallow square-shaped enclosure abutting on the ,s4,w4 side of ,cyrillus4 ,,catherina4--,the largest of the three great formations3 a ring-plain with a very irregular outline1 extending more than #gj miles in a meridional direction1 and of still greater width4 ,the wall is comparatively narrow and low on the ,n4,e4 7#hjjj feet above the floor71 but on the ,n4,w4 it rises to more than double this height1 and is broken by some large depressions4 ,the inner slope on the ,s4,e4 is very gentle1 and includes two bright craters1 but exhibits only slight indications of terraces4 ,the most remarkable features on an otherwise even interior are the large low narrow ring 7with a crater within it71 occupying fully a third of the area of the floor1 and a large ring-plain on the ,s4 side4 ,,madler4--,the interest attaching to this formation is not to be measured by its size1 for it is only about #bj miles in diameter1 but by the remarkable character of its surroundings4 ,its bright regular wall1 rising #fjjj feet on the ,e4 and only about half as much on the ,w41 above a rather dark interior1 is everywhere continuous1 except at one place on the ,n4 ,here there is a narrow gap 7flanked on the ,e4 by a somewhat obscure little crater7 through which a curious bent ridge coming up from the ,n4 passes1 and1 extending on to the floor1 expands into something resembling a central mountain4 ,under a high sun ,madler has a very peculiar appearance4 ,the lofty ,e4 wall is barely perceptible1 while the much lower ,w4 border is conspicuously brilliant2 and the ,e4 half of the floor is dark1 while the remainder1 with two objects representing the loftier portions of the intrusive ridge1 is prominently white4 ,under an evening sun1 with the terminator lying some distance to the ,w41 a very remarkable obscure ring with a low border1 a valley running round it on the ,w4 side1 and two large central mounds1 may be easily traced4 ,this object is connected with ,madler by what appears to be under a higher sun a bright elbow-shaped marking1 in connection with which ,i have often suspected a delicate cleft4 ,between the obtuse-angled bend of this object and the ,w4 wall of ,madler1 two large circular dark spots may be seen under a high sun2 and on the surface of the ,mare ,n4 of it1 a great number of delicate white spots4 ,,beaumont4--,a ring-plain about #cj miles in diameter1 on the ,s4,e4 side of the ,mare ,nectaris1 midway between ,theophilus and ,fracastorius1 with the ,n4,e4 side of which it is connected by a chain of large depressions4 ,its border is lofty1 regular1 and continuous on the ,s4 and ,e41 but on the ,w4 it is low1 and on the ,n4 sinks to such a very inconsiderable height that it is often scarcely traceable4 ,it exhibits two breaks on the ,s4,w41 through one of which passes a coarse valley that ultimately runs on the ,e4 side of the depressions just referred to4 ,the interior is pitted with many craters1 one on the ,w4 side being shallow but of considerable size4 ,i once counted twenty with a #d inch ,cooke achromatic1 and ,dr4 ,sheldon of ,macclesfield subsequently noted many more4 ,a ridge1 prominent under oblique light1 follows a winding course from the ,n4,w4 side of ,beaumont to the ,w4 side of ,theophilus1 and there is another lower ridge ,e4 of it4 ,between them is included a region covered with minute hillocks and asperities4 ,among these objects are certain dusky little crater-cones1 which ,dr4 ,klein of ,cologne regards as true analogues of some terrestrial volcanoes4 ,they are very similar in character to those1 already alluded to1 in the dusky area between ,copernicus and ,gambart4 ,,kant4--,a conspicuous ring-plain1 #bc miles in diameter1 situated in a mountainous district ,e4 of ,theophilus1 with lofty terraced walls and a bright central peak4 ,adjoining it on the ,w4 is a mountain mass1 projecting from the coast-line of the ,mare1 on which there is a peak rising to more than #ad1jjj feet above the surface4 ,,fracastorius4--,this great bay or inflexion at the extreme ,s4 end of the ,mare ,nectaris1 about #fj miles in diameter1 is one of the largest and most suggestive examples of a partially destroyed formation to be found on the visible surface4 ,the ,w4 section of the rampart is practically complete and unbroken1 rising at one peak to a height of #fjjj feet above the interior4 ,it is very broad at its ,s4 end1 and its inner slope descends with a gentle gradient to the floor4 ,towards the ,n41 however1 it rapidly decreases in width1 but apparently not in altitude1 till near its bright pointed ,n4 extremity4 ,under a low sun1 some long deformed crateriform depressions may be seen on the slope1 and a bright little crater on the crest of the border near its ,n4 end4 ,the southern rampart is broken by three large craters1 and a fine valley1 running some distance in a ,s4 direction1 which diminishes gradually in width till it ultimately resembles a cleft1 and terminates at a small crater4 ,the ,e4 border is very lofty and irregular1 rising at the ,n4 corner of the large triangular formation1 which is such a prominent feature upon it1 to a height of #gjjj feet1 and at a point on the ,s4,e4 to considerably more than #hjjj feet above the floor4 ,n4 of the former peak it becomes much lower and narrower1 and is finally only represented by a very attenuated strip of wall1 hardly more prominent than the brighter portions of the border of ,stadius at sunrise1 terminating at an obscure semi-ring-plain4 ,between this and the pointed ,n4 termination of the ,w4 border there is a wide gap1 open to the north for a space of about #cj miles1 appearing1 except under very oblique illumination1 as smooth and as devoid of detail as the grey surface of the ,mare ,nectaris itself4 ,if1 however1 this interval is observed at sunrise or sunset1 it is seen to be not quite so structureless as it appears under different conditions1 for a number of mounds and large humpy swellings1 with low hills and craterlets1 extend across it1 and occupy a position which we are justified in regarding as the site of a section of the rampart1 which1 from some cause or other1 has been completely destroyed and overlaid with the material1 whatever this may be1 of the ,mare ,nectaris4 ,the floor of ,fracastorius is1 as regards the light streaks and other features upon it1 only second in interest to those of ,plato and ,archimedes1 and will repay systematic observation4 ,between thirty and forty light spots and craters have been recorded on its surface1 most of them1 as in these formations1 being situated either on or at the edges of the light streaks4 ,on the higher portion of the interior 7near the centre7 is a curious object consisting apparently of four light spots1 arranged in a square1 with a craterlet in the middle1 all of which undergo 7as ,i have pointed out elsewhere7 notable changes of aspect under different phases4 ,there are at least two distinct clefts on the floor1 one running from the ,w4 wall towards the centre1 and another on the ,s4,e4 side of the interior4 ,the last throws out two branches towards the ,s4,w4 ,,rosse4--,a fine bright deep crater in the ,mare ,nectaris1 ,n4 of the pointed termination of the ,w4 wall of ,fracastorius1 with which it is connected by a bold curved ridge1 with a crater upon it4 ,a ray from ,tycho1 striking along the ,e4 wall of ,fracastorius passes near this object4 ,a rill from near ,bohnenberger terminates at this crater4 ,,polybius4--,a ring-plain1 about #ag miles in diameter1 in the hilly region ,s4,e4 of ,fracastorius4 ,the border is unbroken1 except on the ,n41 where it is interrupted by a group of depressions4 ,there is a long valley on the ,s4,w41 at the bottom of which ,schmidt shows a crater-chain4 ,,neander4--,this ring-plain1 #cd miles in diameter1 a short distance ,w4,s4,w4 of ,piccolomini1 has a somewhat deformed rampart1 which1 however1 except on the ,n41 where there is a narrow gap occupied by a small crater1 is continuous4 ,it rises on the ,e4 nearly #hjjj feet above the floor1 on which there is a central mountain about #bejj feet high4 ,schmidt shows some minor hills1 a large crater on the ,n4,e4 side1 and three smaller craters in the interior4 ,,piccolomini4--,a ring-plain of a very massive type1 about #eg miles in diameter1 ,s4 of ,fracastorius1 with complex and prominently terraced walls1 surmounted by very many peaks2 one of which on the ,e4 attains a height of #ad1jjj feet1 and another1 ,n4 of it1 on the same side1 an altitude of #ae1jjj feet above the interior4 ,the crest of this grand rampart is tolerably continuous1 except on the ,s4,w41 where1 for a distance of twenty miles or more1 its character as regards form and brightness is entirely changed4 ,under a low sun1 instead of a continuous bright border1 we note a wide gap occupied by a dusky rugged plateau1 which falls with a gentle gradient to the floor1 and is traversed by three or four parallel shallow valleys running towards the ,s4 ,i can recall no lunar formation which presents an appearance at all like this3 one is impressed with the idea that it has resulted from the collapse of the upper portion of the wall1 and the flow of some viscous material over the wreck and down the inner slope4 ,the difference between the reflective power of this matter1 whatever may be its nature1 and the broad bright declivities of the inner slopes1 are beautifully displayed at sunset4 ,the cross-valleys are more easily traced under low morning illumination2 but to appreciate the actual structure of the wall1 it should be observed under both phases4 ,the ,n4,w4 section of the border includes many pockets1 or long elliptical depressions1 which at an early stage of sunrise give a scalloped appearance to the crest4 ,except the great bright central mountain with its numerous peaks1 there does not appear to be any prominent detail on the floor4 ,there is a large ring-plain beyond the foot of the glacis on the ,w4 with two craters on the ,e4 side of it1 another on the ,s41 and a fine rill-valley running up to its ,n4 side from near the crest of the ,w4 wall4 ,on the ,n4 side of ,piccolomini is a remarkable group of deformed and overlapping enclosures1 mingled with numberless craters and little depressions4 ,the plain on the ,n4,e4 is crossed by a fine cleft4 ,,pons4--,a complete formation of irregular shape1 about #bj miles in greatest diameter1 on the ,s4,e4 side of the ,altai range1 in ,w4 long4 #ba deg4 ,it consists of a crowd of rings and craters enclosed by a narrow wall4 ,,stiborius4--,an elongated ring-plain1 about #bb miles in diameter1 ,s4 of ,piccolomini1 with a lofty wall1 broken in one place on the ,n4 by a very conspicuous crater4 ,schmidt shows a distinct crater in the centre of the floor4 ,i have only seen a central mountain in this position4 ,there is a large crater on the ,n4,w41 a ring-plain on the ,s4,w4 side1 and a multitude of little craters on the surrounding plain4 ,,riccius4--,a ring-plain1 #ea miles in diameter1 of a very irregular type1 ,s4,e4 of the last4 ,it is enclosed by a complex wall 7which is in places double71 broken by large rings on the ,s4 ,the very conspicuous little ring-plain ,riccius ,a is situated on the ,n4 of it1 and other less prominent features4 ,the interior includes a bright crater and some smaller objects of the same class4 ,,zagut4--,the most easterly of a group of closely associated irregular walled-plains1 of which ,lindenau and ,rabbi ,levi are the other members1 all evidently deformed and modified in shape by their proximity4 ,it is about #de miles in diameter1 and is enclosed by a wall which on the ,s4,w4 attains a height of about #iejj feet1 and is much broken on the ,n4 by a number of depressions4 ,a large ring-plain1 some #bj miles in diameter1 occupies a considerable portion of the ,w4 side of the interior2 ,e4 of which1 and nearly central1 there is a large bright crater1 but apparently no other conspicuous details4 ,on the ,s4,e4 side of ,zagut lies an elliptical ring-plain1 about #bh miles in diameter1 named by ,schmidt ,,celsius4 ,the border of this is open on the ,n41 the gap being occupied by a large crater1 whose ,s4 wall is wanting1 so that the interiors of both formations are in communication4 ,,lindenau4--,this formation1 about #ce miles in diameter1 is bounded on the ,w4 by a regular unbroken wall nearly #hfjj feet in height2 but which on the ,e4 and ,n4,e4 is far loftier and more complex1 rising to about #ab1jjj feet above the floor1 consisting of four or more distinct ramparts1 separated by deep valleys1 and extending towards ,rabbi ,levi4 ,neison points out that under a high light ,lindenau appears to have a bright uniform single wall4 ,there is a small central mountain and some minor inequalities in the interior4 ,,rabbi ,,levi4--,a larger but less obvious formation than either of its neighbours1 ,zagut and ,lindenau1 abutting on the ,s4 side of them4 ,it is about #ee miles in diameter1 and is enclosed by a border somewhat difficult to trace in its entirety1 except under oblique light4 ,there are some large craters within it1 of which one on the ,n4 side of the floor is especially prominent4 ,,nicolai4--,a tolerably regular ring-plain1 #ah miles in diameter1 ,s4 of ,riccius1 with a border1 rising more than #fjjj feet above a level floor1 on the ,n4 side of which ,schmidt shows a minute crater4 ,the bright plain surrounding this formation abounds in small craters2 and on the ,w4 is a number of curious enclosures1 many of them overlapping4 ,,vlacq4--,a member of a magnificent group of closely associated formations situated on the greatly disturbed area between ,w4 long4 #cj deg4 and #de deg4 and ,s4 lat4 #ej deg4 and #fj deg4 ,it is #eg miles in diameter1 and is enclosed by terraced walls1 rising on the ,w4 about #hjjj feet1 and on the ,e4 more than #aj1jjj feet above the floor4 ,they are broken on the ,s4 by a fine crater4 ,in addition to a conspicuous central peak1 there are several small craters1 and low short ridges in the interior4 ,,hommel4--,adjoins ,vlacq on the ,s4 ,it is a somewhat larger and a far more irregular formation4 ,on every side except the ,w41 where the border is unbroken1 and descends with a gentle slope to the dark interior2 ring- plains and smaller depressions encroach on its outline1 perhaps the most remarkable being ,hommel a on the ,n41 which has an especially brilliant wall1 that includes a conspicuous central mountain1 a large crater1 and other details4 ,the best phase for observing ,hommel and its surroundings is when the ,w4 wall is just within the evening terminator4 ,,pitiscus4--,the most regular of the ,vlacq group4 ,it is situated on the ,n4,e4 of ,hommel 7a curious oblong-shaped enclosure1 ,hommel h1 with a very attenuated ,e4 wall1 and a large crater on a floor1 standing at a higher level than that of ,pitiscus1 intervening74 ,it is #eb miles in diameter1 and is surrounded by an apparently continuous rampart1 except on the ,e41 where there is a crater1 and on the ,s4,w41 where it abuts on ,hommel h4 ,here there is a wide gap crossed by what has every appearance of being a fault1 resembling that in ,phocylides on a smaller scale4 ,there is a fine crater on the ,n4 side of the interior connected with the ,s4 wall by a bright ridge4 ,just beyond the ,e4 border there is a shallow ring-plain of a very extraordinary shape4 ,,nearch4--,a ring-plain1 about #ce miles in diameter1 on the ,s4,w4 of ,hommel1 forming part of the ,vlacq group4 ,,tannerus4--,a ring-plain1 about #ai miles in diameter1 between ,mutus and ,bacon4 ,it has a central mountain4 ,,mutus4--,a fine but foreshortened walled plain1 #ea miles in diameter4 ,there are two ring-plains of about equal size on the floor1 one on the ,n41 and the other on the ,s4 side4 ,the wall on the ,w4 rises to nearly #ad1jjj feet above the interior4 ,,manzinus4--,a walled plain1 nearly #fb miles in diameter1 with a terraced rampart rising to a height of more than #ad1ejj feet above the interior4 ,schmidt shows three craterlets on the floor1 but no traces of the small central peak which is said to stand thereon1 but to be only visible in large telescopes4 ,,schomberger4--,a large walled-plain adjoining ,simpelius on the ,s4,w4 ,too near the limb for satisfactory observation4 ,,west ,,longitude #bj deg4 ,,to #j deg4 ,,delambre4--,a conspicuous ring-plain1 #cb miles in diameter1 a little ,s4 of the equator1 in ,w4 long4 #ag deg4 #cj min41 with a massive polygonal border1 terraced within1 rising on the ,w4 to the great height of #ae1jjj feet above the interior1 but to little more than half this on the opposite side4 ,its outline approximates to that of a pentagon with slightly curved sides4 ,a section on the ,s4,e4 exhibits an inflexion towards the centre4 ,the crest is everywhere continuous except on the ,n41 where it is broken by a deep crater with a bright rim4 ,the north-easterly trend of the ridges and hillocks on the ,e4 is especially noteworthy4 ,the central peak is not prominent1 but close under it on the ,e4 is a deep fissure1 extending from near the centre1 and dying out before it reaches the ,s4 border4 ,at the foot of the ,n4,e4 glacis there are traces of a ring with low walls4 ,,theon1 ,,sen4--,a brilliant little ring-plain1 ,e4,n4,e4 of ,delambre1 #aa miles in diameter1 and of great depth1 with a regular and perfectly unbroken wall4 ,north of it is a bright little crater4 ,,theon1 ,,jun4--,a ring-plain similar in size and in other respects to the last1 situated about #bc miles ,s4 of it on a somewhat dusky surface4 ,between the pair is a curious oblong-shaped mountain mass2 and on the ,e4 a long cliff 7of no great altitude1 but falling steeply on the ,e4 side7 extending ,s4 towards ,taylor a4 ,just below the escarpment1 ,i find a brilliant little pair of craterlets1 of which ,neison only shows one4 ,,alfraganus4--,a large bright crater1 about #i miles in diameter1 with very steep walls1 some distance ,s4,s4,w4 of ,delambre1 and standing on the ,w4 edge of a large but very shallow and irregular depression ,w4 of ,taylor4 ,there is a remarkable chain of craters on the ,w4 of it4 ,alfraganus is the centre of a system of light streaks radiating in all directions1 one ray extending through ,cyrillus to ,fracastorius4 ,,taylor4--,a deep spindle-shaped ring-plain1 ,s4 of ,delambre1 about #bb miles in length4 ,the wall appears to be everywhere continuous1 except at the extreme ,n4 and ,s4 ends1 where there are small craters4 ,the outer slopes1 both on the ,e4 and ,w41 are very broad and prominent1 but apparently not terraced4 ,there is an inconspicuous central hill4 ,on the ,w4 is the irregular enclosure1 already referred to under ,alfraganus4 ,three or four short winding valleys traverse the ,n4 edge of this formation1 and descend to the dark floor4 ,on the ,n4,e4 is the remarkable ring-plain ,taylor a1 #ah miles in diameter1 rising1 at an almost isolated mountain mass on the ,e4 border1 to a height of #gjjj feet above the interior4 ,the more regular and ,w4 section of this formation is not so lofty1 and falls with a gentle slope to the dark uneven floor1 on which there is some detail in the shape of small bright ridges and mounds4 ,on the surface1 ,n4,w4 of ,taylor a1 is a curious linear row of bright little hills4 ,taylor and the vicinity is better seen under low evening illumination than under morning light4 ,,hipparchus4--,except under a low sun1 this immense walled-plain is by no means so striking an object as a glance at its representation on a chart of the moon would lead one to expect2 for the border1 in nearly every part of it1 bears unmistakable evidence of wreck and ruin1 its continuity being interrupted by depressions1 transverse valleys1 and gaps1 and it nowhere attains a great altitude4 ,this imperfect enclosure extends #ig miles from ,n4 to ,s41 and about #hh miles from ,e4 to ,w41 and in shape approximates to that of a rhombus with curved sides4 ,one of the most prominent bright craters on its border is ,hipparchus ,g1 on the ,w4 ,another1 of about the same size1 is ,hipparchus ,e1 on the ,n4 of ,horrocks4 ,on the ,e4 there is a moderately bright crater1 ,hipparchus ,f2 and ,s4 of this1 on the same side1 two others1 ,k and ,i4 ,the interior is crossed by many ridges1 and near the centre includes the relics of a low ring1 traversed by a narrow rill-like valley4 ,schmidt shows a cleft running from ,f across the floor to the ,s4 border4 ,a valuable monograph of ,hipparchus1 by ,mr4 ,w4,b4 ,birt1 was published in #ahgj4 ,,horrocks4--,this fine ring-plain1 #ah miles in diameter1 stands on the ,n4 side of the interior of ,hipparchus1 close to the border4 ,it has a continuous wall1 rising on the ,e4 to a height of nearly #hjjj feet above the interior1 and a distinct central mountain4 ,,halley4--,a ring-plain1 #ba miles in diameter1 on the ,s4,w4 border of ,hipparchus1 with a bright wall1 rising at one point on the ,e4 to a height of #gejj feet above the floor1 which is depressed about #djjj feet below the surface4 ,two craterlets on the floor1 one discovered by ,birt on ,rutherfurd's photogram of #ahfe1 and the other by ,gaudibert1 raised a suspicion of recent lunar activity within this ring4 ,a magnificent valley1 shown in part by ,schmidt as a crater-row1 runs from the ,s4 of ,halley to the ,w4 side of ,albategnius4 ,,hind4--,a ring-plain1 #af miles in diameter1 a few miles ,w4 of ,halley1 with a peak on its ,e4 wall #aj1jjj feet above the floor4 ,the border is broken both on the ,s4,e4 and ,n4,e4 by small craters4 ,horrocks1 ,halley1 and ,hind may be regarded as strictly belonging to ,hipparchus4 ,,albategnius4--,a magnificent walled-plain1 #fe miles in diameter1 adjoining ,hipparchus on the ,s41 surrounded by a massive complex rampart1 prominently terraced1 including many depressions1 and crossed by several valleys4 ,it is surmounted by very lofty peaks1 one of which on the ,n4,e4 stands nearly #ae1jjj feet above the floor4 ,the great ring-plain ,albategnius ,a1 #bh miles in diameter1 intrudes far within the limits of the formation on the ,e41 and its towering crest rises more than #aj1jjj feet above its floor1 on which there is a small central mountain4 ,the central mountain of ,albategnius is more than #djjj feet high1 and1 with the exception of a few minor elevations1 is the only prominent feature in the interior1 though there are many small craters4 ,schmidt counted forty with the ,berlin refractor1 among them #ab on the ,e4 side1 arranged like a string of pearls4 ,,parrot4--,an irregularly-shaped formation1 #da miles in diameter1 ,s4 of ,albategnius1 with a very discontinuous margin1 interrupted on every side by gaps and depressions1 large and small2 the most considerable of which is the regular ring-plain ,parrot a1 on the ,e4 ,an especially fine valley1 shown by ,schmidt to consist in part of large inosculating craters1 cuts through the wall on the ,s4,w41 and runs on the ,e4 side of ,argelander towards ,airy4 ,the floor of ,parrot is very rugged4 ,,descartes4--,this object1 about #cj miles in diameter1 situated ,n4,w4 of ,abulfeda1 is bounded by ill-defined1 broken1 and comparatively low walls2 interrupted on the ,s4,e4 by a fine crater1 ,descartes ,a1 and on the ,s4,w4 by another1 smaller4 ,there is also a brilliant crater outside on the ,n4,w4 ,schmidt shows a crater-row on the floor1 which ,i have seen as a cleft4 ,,dollond4--,a bright crater1 about #f miles in diameter1 on the ,n4,e4 side of ,descartes4 ,between it and the latter there is a rill-valley4 ,,tacitus4--,a bright ring-plain1 about #bh miles in diameter1 a few miles ,e4 of ,catherina1 with a lofty wall rising both on the ,e4 and ,w4 to more than #aa1jjj feet above the floor4 ,its continuity is broken on the ,n4 by a gap occupied by a depression1 and there is a conspicuous crater below the crest on the ,s4,w4 ,the central mountain is connected with the ,n4 wall by a ridge1 recalling the same arrangement within ,madler4 ,a range of lofty hills1 an offshoot of the ,altai range1 extends from ,tacitus towards ,fermat4 ,,almanon4--,this ring-plain1 with its companion ,abulfeda on the ,n4,e41 is a very interesting telescopic object4 ,it is about #cf miles in diameter1 and is surrounded by an irregular border of polygonal shape1 the greatest altitude of which is about #fjjj feet above the floor on the ,w4 ,it is slightly terraced1 and is broken on the ,s4 by a deep crater pertaining to the bright and large formation ,tacitus b1 the ,e4 border of which casts a fine double-peaked shadow at sunrise4 ,on the ,n4,w4 there is another bright crater1 the largest of the row1 running in a ,w4,s4,w4 direction1 and forming a ,w4 extension of the remarkable crater-chain tangential to the borders of ,almanon and ,abulfeda4 ,the only objects on the floor are three little hills1 in a line1 near the centre1 a winding ridge on the ,w4 side of it1 and two or three other low elevations4 ,,abulfeda4--,a larger and more massive formation than ,almanon1 #ci miles in diameter1 the ,e4 wall rising about #aj1jjj feet above the interior1 which is depressed more than #cjjj feet4 ,it is continuous on the ,w41 but much broken by transverse valleys on the ,s4,e41 and by little depressions on the ,n4 ,on the ,s4,e4 originates the very curious bright crater-row which runs in a straight line to the ,n4,w4 wall of ,almanon1 crossing for the first few miles the lofty table-land lying on the ,s4,e4 side of the border4 ,with the exception of a low central mountain1 the interior of ,abulfeda contains no visible detail4 ,the rampart is finely terraced on the ,e4 and ,w4 ,the ,e4 glacis is very rugged4 ,,argelander4--,this conspicuous ring-plain1 about #bj miles in diameter1 is1 if we except two smaller inosculating rings on the ,s4,w4 flank of ,albategnius1 the most northerly of a remarkable serpentine chain of seven moderately-sized formations1 extending for nearly #ahj miles from the ,s4,w4 of ,parrot to the ,n4 side of ,blanchinus4 ,its border is lofty1 slightly terraced within1 and includes a central peak4 ,,airy4--,about #bb miles in diameter1 connected with ,argelander by a depression bounded by linear walls4 ,its border1 double on the ,s4,e41 is broken on the ,s4 by a prominent crater1 with a smaller companion on the ,w4 of it2 and again on the ,n4,e4 by another not so conspicuous4 ,it has a central peak4 ,the next link in the chain of ring-plains is ,airy c1 a very irregular object1 somewhat larger1 and with1 for the most part1 linear walls4 ,,donati4--,a ring-plain on the ,s4 of ,airy c1 about #bb miles in greatest length4 ,it is very irregular in outline1 with a lofty broken border1 especially on the ,n4 and ,s41 where there are wide gaps4 ,there is another ring on the ,s4,e4 ,,faye4--,the direction of the chain swerves considerably towards the ,e4 at this formation1 which resembles ,donati both in size and in irregularity of outline4 ,the wall1 where it is not broken1 is slightly terraced4 ,there is a craterlet on the ,s4 rim and a central crater in the interior4 ,,delaunay4--,adjoins ,faye on the ,s4,e41 and is a larger and more complex object1 of irregular form1 with very lofty peaks on its border4 ,a prominent ridge of great height traverses the formation from ,n4 to ,s41 abutting on the ,w4 border of ,lacaille4 ,delaunay is the last link in the chain commencing with ,argelander4 ,,lacaille4--,an oblong enclosure situated on the ,n4 side of ,blanchinus1 and apparently about #cj miles in greatest diameter4 ,the border is to a great extent linear and continuous on the ,n41 but elsewhere abounds in depressions4 ,two large inosculating ring-plains are associated with the ,n4,e4 wall4 ,,blanchinus4--,a large walled-plain on the ,w4 of ,purbach and abutting on the ,s4 side of ,lacaille4 ,it much resembles ,purbach in shape1 but has lower walls4 ,schmidt shows a crater on the ,n4 side of the floor1 which ,i have seen1 and a number of parallel ridges which have not been noted1 probably because they are only visible under very oblique light4 ,,geber4--,a bright ring-plain1 #be miles in diameter1 ,s4 of ,almanon1 with a regular border1 rising to a height on the ,w4 of nearly #ijjj feet above the floor4 ,there is a small crater on the crest of the ,s4 wall1 and another on the ,n4 ,a ring-plain about #h miles in diameter adjoins the formation on the ,n4,e4 ,according to ,neison1 there is a feeble central hill1 which1 however1 is not shown by ,schmidt4 ,,sacrobosco4--,this is one of those extremely abnormal formations which are almost peculiar to certain regions in the fourth quadrant4 ,it is about #ej miles in greatest diameter1 and is enclosed by a rampart of unequal height1 rising on the ,e4 to #ab1jjj feet above the floor1 but sinking in places to a very moderate altitude4 ,on the ,n4 its contour is1 if possible1 rendered still more irregular by the intrusion of a smaller ring-plain4 ,on the ,n4,e4 side of the floor stands a very bright little crater and two others on the ,s4 of the centre1 each with central mountains4 ,,fermat4--,an irregular ring-plain #be miles in diameter on the ,w4 of ,sacrobosco4 ,its partially terraced wall is broken on the ,n4 by a gap which communicates with the interior of a smaller formation4 ,there are some low hills on the floor1 which is depressed #fjjj feet below the crest of the border4 ,,azophi4--,a prominent ring-plain1 #cj miles in diameter1 ,e4,n4,e4 of ,sacrobosco1 its lofty barrier towering nearly #aa1jjj feet above a somewhat dusky interior1 which includes some light spots4 ,a massive curved mountain arm runs from the ,s4 side of this formation to a small ring-plain ,w4 of ,playfair4 ,,abenezra4--,when observed near the morning terminator1 this noteworthy ring-plain1 #bg miles in diameter1 seems to be divided into two by a curved ridge which traverses the formation from ,n4 to ,s41 and extends beyond its limits4 ,the irregular border rises on the ,w4 to a height of more than #ad1jjj feet above the deeply-sunken floor1 which includes several craters1 hills1 and ridges4 ,,apianus4--,a magnificent ring-plain1 #ch miles in diameter1 ,n4,w4 of ,aliacensis1 with lofty terraced walls1 rising on the ,n4,e4 to about #ijjj feet above the interior1 and crowned on the ,w4 by three large conspicuous craters4 ,the border is broken on the ,n4 by a smaller depression and a large ring with low walls4 ,the dark-grey floor appears to be devoid of conspicuous detail4 ,,playfair4--,a ring-plain1 #bh miles in diameter1 with massive walls4 ,it is situated on the ,n4 of ,apianus1 and is connected with it by a mountain arm4 ,the rampart is tolerably continuous1 but varies considerably in altitude1 rising on the ,s4 to a height of more than #hjjj feet above the interior4 ,on the ,e41 extending towards ,blanchinus1 is a magnificent unnamed formation1 bounded on the ,e4 by a broad lofty rampart flanking ,blanchinus1 ,lacaille1 ,delaunay1 and ,faye2 and on the ,w4 by ,playfair and the mountain arm just mentioned4 ,it is fully #fj miles in length from ,n4 to ,s4 ,sunrise on this region affords a fine spectacle to the observer with a large telescope4 ,the best phase is when the morning terminator intersects ,aliacensis1 as at this time the long jagged shadows of the ,e4 wall of ,playfair and of the mountain arm are very prominent on the smooth1 greyish-blue surface of this immense enclosure4 ,,pontanus4--,an irregular ring-plain1 #bh miles in diameter1 ,s4,s4,w4 of ,azophi1 with a low broken border1 interrupted on the ,s4,w4 by a smaller ring-plain1 which forms one of a group extending towards the ,s4,w4 ,the dark floor includes a central mountain4 ,,aliacensis4--,this ring-plain1 #ec miles in diameter1 with its neighbour ,werner on the ,n4,e41 are beautiful telescopic objects under a low sun4 ,its lofty terraced border rises at one peak on the ,e4 to the tremendous height of #af1ejj feet1 and at another on the opposite side to nearly #ab1jjj feet above the floor4 ,the wall on the ,s4 is broken by a crater1 and on the ,w4 traversed by narrow passes4 ,there is also a prominent crater on the inner slope of the ,n4,e4 wall4 ,the floor includes a small mountain1 several little hills1 and a crater4 ,,werner4--,a ring-plain1 #de miles in diameter1 with a massive rampart crowned by peaks almost as lofty as any on that of ,aliacensis1 and with terraces fully as conspicuous4 ,it has a magnificent central mountain1 #dejj feet high4 ,at the foot of the ,n4,e4 wall ,madler observed a small area1 which he describes as rivalling the central peak of ,aristarchus in brilliancy4 ,webb1 however1 was unable to confirm this estimate1 though he noted it as very bright1 and saw a minute black pit and narrow ravine within it4 ,neison subsequently found that the black pit is a crater-cone4 ,it would perhaps be rash1 with our limited knowledge of minute lunar detail1 to assert that ,madler over-estimated the brightness of this area1 which may have been due to a recent deposit round the orifice of the crater-cone4 ,,poisson4--,an irregular formation on the ,w4 of ,aliacensis1 extending about #ej miles from ,w4 to ,e41 but much less in a meridional direction4 ,its ,n4 limits are marked by a number of overlapping ring-plains and craters1 and it is much broken elsewhere by smaller depressions4 ,the ,e4 wall is about #gjjj feet in height4 ,,gemma ,,frisius4--,a great composite walled-plain1 #hj miles or more in length from ,n4 to ,s41 with a wall rising at one place nearly #ad1jjj feet above the floor4 ,it is broken on the ,n4 by two fine ring-plains1 each about #bj miles in diameter1 and on the ,e4 by a third open to the ,e4 ,there is a central mountain1 and several small craters on the floor1 especially on the ,w4 side4 ,,busching4--,a ring-plain ,s4 of ,zagut1 about #cf miles in diameter1 with a moderately high but irregular wall4 ,there are several craterlets within and some low hills4 ,,buch4--,adjoins ,busching on the ,s4,e4 ,it is about #ca miles in diameter1 and has a less broken barrier4 ,there is a large crater on the ,e4 wall1 and another smaller one on the ,s4,w4 ,schmidt shows nothing on the floor1 but ,neison noted two minute crater-cones4 ,,maurolycus4--,this unquestionably ranks as one of the grandest walled- plains on the moon's visible surface1 and when viewed under a low sun presents a spectacle which is not easily effaced from the mind4 ,like so many of the great enclosures in the fourth quadrant1 it impresses one with the notion that we have here the result of the crowding together of a number of large rings which1 when they were in a semi-fluid or viscous condition1 mutually deformed each other4 ,it extends fully #aej miles from ,e4 to ,w41 and more from ,n4 to ,s42 so it may be taken to include an area on the lunar globe which is1 roughly speaking1 equal to half the superficies of ,ireland4 ,this vast space1 bounded by one of the loftiest1 most massive1 and prominently-terraced ramparts1 includes ring-plains1 craters1 crater-rows1 and valleys1--in short1 almost every type of lunar formation4 ,it towers on the ,e4 to a height of nearly #ad1jjj feet above the interior1 and on the ,w41 according to ,schmidt1 to a still greater altitude4 ,a fine rill-valley curves round the outer slope of the ,w4 wall1 just below its crest1 which is an easy object in a #h #a_/b inch reflector when the opposite border is on the morning terminator1 and could doubtless be seen in a smaller instrument2 and there is an especially brilliant crater on the ,s4 border1 which is not visible till a somewhat later stage of sunrise4 ,the central mountain is of great altitude1 its loftiest peaks standing out amid the shadow long before a ray of sunlight has reached the lower slopes of the walls4 ,it is associated with a number of smaller elevations4 ,i have seen three considerable craters and several smaller ones in the interior4 ,,barocius4--,a massive formation1 about #ej miles in diameter1 on the ,s4,w4 side of ,maurolycus1 whose border it overlaps and considerably deforms4 ,its wall rises on the ,e4 to a height of #ab1jjj feet above the floor1 and is broken on the ,n4,w4 by two great ring-plains4 ,on the inner slope of the ,s4,e4 border is a curious oblong enclosure4 ,there is nothing remarkable in the interior4 ,on the dusky grey plain ,w4 of ,maurolycus and ,barocius there is a number of little formations1 many of them being of a very abnormal shape1 which are well worthy of examination4 ,i have seen two short unrecorded clefts in connection with these objects4 ,,stofler4--,a grand object1 very similar in size and general character to ,maurolycus1 its neighbour on the ,w4 ,to view it and its surroundings at the most striking phase1 it should be observed when the morning terminator lies a little ,e4 of the ,w4 wall4 ,at this time the jagged1 clean-cut1 shadows of the peaks on ,faraday and the ,w4 border1 the fine terraces1 depressions1 and other features on the illuminated section of the gigantic rampart1 and the smooth bluish-grey floor1 combine to make a most beautiful telescopic picture4 ,at a peak on the ,n4,e41 the wall attains a height of nearly #ab1jjj feet1 but sinks to a little more than a third of this height on the ,e4 ,it is apparently loftiest on the ,n4 ,the most conspicuous of the many craters upon it is the bright deep circular depression ,e4 on the ,s4 wall1 and another1 rather larger and less regular1 on the ,n4,w41 which has a very low rim on the side facing the floor1 and a craterlet on either side of the apparent gap4 ,a large lozenge-shaped enclosure abuts on the wall1 near the crater ,e41 with a border crowned by a number of little peaks1 which at an early stage of sunrise resemble a chaplet of pearls4 ,the floor of ,stofler is apparently very level1 and in colour recalls the beautiful steel-grey tone of ,plato seen under certain conditions4 ,i have noted several distinct little craters on its surface1 mostly on the ,n4,e4 side2 and on the ,e4 side a triangular dark patch1 close to the foot of the wall1 very similar in size and appearance to those within ,alphonsus4 ,,faraday4--,a large ring-plain1 about #ce miles in diameter1 overlapping the ,s4,w4 border of ,stofler2 its own rampart being overlapped in its turn by two smaller ring-plains on the ,s4,e41 and by two still smaller formations 7one of which is square-shaped7 on the ,n4,w4 ,the wall is broad and very massive on the ,e4 and ,n4,e41 prominently terraced1 and includes many brilliant little craters4 ,schmidt shows a ridge and several craters in the interior4 ,,licetus4--,an irregular formation1 about #ej miles in maximum width1 on the ,s4 of ,stofler1 with the flanks of which it is connected by a coarse valley4 ,neison points out that it consists of a group of ring-plains united into one1 owing to the separating walls having been partially destroyed4 ,this seems to be clearly the case1 if ,licetus is examined under a low sun4 ,on the ,e4 side of the ,n4 portion of the formation1 the wall rises to nearly #ac1jjj feet4 ,,fernelius4--,a ring-plain1 about #cj miles in diameter1 abutting on the ,n4 wall of ,stofler4 ,it is overlapped on the ,e4 by another similar formation of about half its size4 ,there are many craters and depressions on the borders of both1 and a large crater between the smaller enclosure and the ,n4,e4 outer slope of ,stofler4 ,schmidt shows eight craters on the floor of ,fernelius4 ,,nonius4--,a ring-plain1 about #bj miles in diameter1 abutting on the ,n4 wall of ,fernelius4 ,there is a prominent bright crater on the ,w4 of it1 and another on the ,n41 from which a delicate valley runs towards the ,w4 side of ,walter4 ,,clairaut4--,a very peculiar formation1 about #dj miles in diameter1 ,s4 of ,maurolycus1 affording another good example of interference and overlapping4 ,the continuity of its border1 nowhere very regular1 has been entirely destroyed on the ,s4 by the subsequent formation of two large rings1 some #aj or #ab miles in diameter1 the more easterly of which has1 in its turn1 been partially wrecked on the ,n4 by a smaller object of the same class4 ,there is also a ring-plain ,n4,e4 of ,clairaut1 which has very clearly modified the shape of the border on this side4 ,two craters on the floor of ,clairaut are easy objects4 ,,bacon4--,a very fine ring-plain1 #dj miles in diameter1 ,s4,w4 of ,clairaut4 ,at one peak on the ,e4 the terraced wall rises to nearly #ad1jjj feet above the interior4 ,it is broken on the ,s4 by three or four craters4 ,on the ,w4 there is an irregular inconspicuous enclosure1 whose contiguity has apparently modified the shape of the border4 ,there are two large rings on the ,n4 7the more easterly having a central peak71 and a third on the ,e4 ,the floor appears to be devoid of prominent detail4 ,,cuvier4--,a walled-plain1 about #ej miles in diameter1 on the ,s4,e4 of ,clairaut4 ,the border on the ,e4 rises to #ab1jjj feet2 and on the ,n4,w4 is much broken by depressions4 ,neison has seen a mound1 with a minute crater ,w4 of it1 on the otherwise undisturbed interior4 ,,jacobi4--,a ring-plain ,s4 of ,cuvier1 about #dj miles in diameter1 with walls much broken on the ,n4 and ,s41 but rising on the ,e4 to nearly #aj1jjj feet4 ,there is a group of craters 7nearly central7 on the floor4 ,the region ,s4 of this formation abounds in large unnamed objects4 ,,lilius4--,an irregular ring-plain1 #ci miles in diameter1 with a rampart on the ,e4 nearly #aj1jjj feet above the floor4 ,a smaller ring between it and ,jacobi has considerably inflected the wall towards the interior4 ,it has a conspicuous central mountain4 ,,zach4--,a massive formation1 #df miles in diameter1 on the ,s4 of ,lilius1 with prominently terraced walls1 rising on the ,e4 to #ac1jjj feet above the interior4 ,a small ring-plain1 whose wall stands #fjjj feet above the floor1 is associated with the ,n4 border4 ,two other rings1 on the ,s4,w4 and ,n4,e4 respectively1 have craters on their ramparts and central hills4 ,,pentland4--,a fine conspicuous formation under a low sun1 even in a region abounding in such objects4 ,it is about #ej miles in diameter1 with a border exceeding in places #aj1jjj feet in height above the floor1 which includes an especially fine central mountain4 ,,kinau4--,one of the group of remarkable ring-plains extending in a ,n4,w4 direction from ,pentland4 ,,simpelius4--,another grand circumvallation1 almost as large as ,pentland1 but unfortunately much foreshortened4 ,one of its peaks on the ,e4 rises to a height of more than #ab1jjj feet above the floor1 on which there is a small central mountain4 ,between ,simpelius and ,pentland are several ring- plains1 most of which appear to have been squeezed and deformed into abnormal shapes4 ,,curtius4--,a magnificent formation1 about #ej miles in diameter1 with one of the loftiest ramparts on the visible surface1 rising at a mountain mass on the ,n4,e4 to more than #bb1jjj feet1 an altitude which is only surpassed by peaks on the walls of ,newton and ,casatus4 ,there is a bright crater on the ,s4,e4 border and another on the ,w4 ,the formation is too near the ,s4 limb for satisfactory scrutiny4 ,between ,curtius and ,zach is a fine group of unnamed enclosures4 ,,appendix ,,description ,,of ,,the ,,map ,the accompanying map1 eighteen inches in diameter1 represents the moon under mean libration4 ,meridian lines and parallels of latitude are drawn at every #aj deg41 except in the case of the meridians of #hj deg4 ,e4 and ,w4 longitude1 which are omitted to avoid confusion1 and as being practically needless4 ,these lines will enable the observer1 with the aid of the ,tables in the ,appendix1 to find the position of the terminator at any time required4 ,as astronomical telescopes exhibit objects inverted1 maps of the moon are always drawn upside down1 and with the right and left interchanged1 as in the diagram above1 which also shows how the quadrants are numbered4 ,this circle drawing of circle1 intended to be 4#aegjh in diameter1 represents a circle of one degree in diameter at the centre of the map1 and as the length of one selenographical degree is #ah4hga miles1 it represents an area of nearly #bhj square miles4 ,the catalogue is so arranged that1 beginning with the ,w4 limb1 and referring to the lists under the first and fourth1 and the second and third quadrants1 all the formations falling within the meridians #ij deg4 to #fj deg41 #fj deg4 to #dj deg41 #dj deg4 to #bj deg41 #bj deg4 to #j deg4 7the central meridian71 and from #j deg4 to #bj deg41 and so on1 to the ,e4 limb1 will be found in convenient proximity in the text4 ,in the ,catalogue1 ,n4 ,s4 ,e4 ,w4 are used as abbreviations for the cardinal points4 ,,list ,,of ,,the ,,maria1 ,,or ,,grey ,,plains1 ,,termed ,,seas1 c4 ,,first ,,quadrant4 ,mare ,tranquilitatis 7nearly the whole71 page #e4 11 ,foecunditatis 7the ,n4 portion71 #e4 11 ,serenitatis1 #e4 11 ,crisium1 #f4 11 ,frigoris 7a portion71 #e4 11 ,vaporum 7nearly the whole71 #f4 11 ,humboldtianum1 #f4 11 ,smythii 7a portion71 #ci4 ,lacus ,mortis1 #ec4 11 ,somniorum4 ,palus ,somnii4 11 ,nebularum 7a portion71 #fb4 11 ,putredinis1 #fa4 ,sinus ,medii 7a portion71 #f4 ,,second ,,quadrant4 ,mare ,imbrium1 #e4 11 ,nubium 7the ,n4 portion71 #e4 11 ,frigoris 7a portion71 #e4 11 ,vaporum 7a portion71 #f4 ,oceanus ,procellarum 7the ,n4 portion71 #e4 ,palus ,nebularum 7a portion71 #fb4 ,sinus ,iridum1 #hj4 11 ,medii 7a portion71 #f4 11 ,roris1 #ij4 11 ,aestuum4 ,,third ,,quadrant4 ,mare ,nubium 7the greater portion71 #e4 11 ,humorum1 #f4 ,oceanus ,procellarum 7the ,s4 portion71 #e4 ,sinus ,medii 7a small portion71 #f4 ,,fourth ,,quadrant4 ,mare ,foecunditatis 7the greater portion71 #e4 11 ,nectaris1 #g4 11 ,tranquilitatis 7a small portion71 #e4 11 ,australe1 #abg4 11 ,smythii 7a portion71 #ci4 ,sinus ,medii 7a portion71 #f4 ,,list ,,of ,,some ,,of ,,the ,,most ,,prominent ,,mountain ,,ranges1 ,,promontories1 ,,isolated ,,mountains1 ,,and ,,remarkable ,,hills4 ,,first ,,quadrant4 ,the ,alps4 ,the western portion of the range4 ,the ,apennines4 ,the extreme northern part of the range4 ,the ,caucasus4 ,the ,haemus4 ,the ,taurus4 ,the ,north ,polar ,range4 ,on the limb extending from ,n4 lat4 #ha deg4 towards the ,e4 ,the ,humboldt ,mountains4 ,on the limb from ,n4 lat4 #gb deg4 to ,n4 lat4 #ec deg4 ,mount ,argaeus4 ,a mountain mass rising some #hjjj feet above the ,mare ,serenitatis in ,n4 lat4 #bj deg41 ,w4 long4 #bh deg41 ,n4,w4 of ,dawes4 ,prom4 ,acherusia4 ,a bright promontory at the ,w4 extremity of the ,haemus range1 rising nearly #ejjj feet above the ,mare ,serenitatis4 ,n4 lat4 #ag deg41 ,w4 long4 #bb deg4 ,cape ,agarum4 ,the ,n4 end of a projecting headland on the ,s4,w4 side of the ,mare ,crisium1 in ,n4 lat4 #ad deg41 ,w4 long4 #ff deg41 rising nearly #aa1jjj feet above the ,mare4 ,le ,monnier ,a4 ,an isolated mountain more than #cjjj feet high1 standing about midway between the extremities of the bay3 probably a relic of a once complete ring4 ,secchi4 ,south of this formation there is a lofty prominent isolated mountain4 ,manilius ,a and beta4 ,two conspicuous mountains ,n4 of ,manilius2 ,a1 the more westerly1 being more than #ejjj feet1 and beta about #bjjj feet in height4 ,autolycus ,a4 ,a mountain of considerable altitude1 ,s4 of this formation4 ,mont ,blanc4 ,principal peak1 ,n4 lat4 #df deg41 ,w4 long4 #j deg4 #cj min41 nearly #ab1jjj feet in height4 ,cassini epsilon and delta4 ,two adjoining mountain masses ,n4 of ,cassini1 more than #ejjj feet high4 ,eudoxus4 ,s4,e4 of this formation1 in ,n4 lat4 #dc deg41 ,w4 long4 #aj deg41 are two bright mountain masses1 the more southerly rising #gjjj1 and the other #djjj feet above the surface4 ,mount ,hadley4 ,the northern extremity of the ,apennines1 in ,n4 lat4 #bg deg4 ,w4 long4 #e deg41 rising more than #ae1jjj feet above the ,mare4 ,mount ,bradley4 ,a promontory of the ,apennines1 in ,n1 lat4 #bc deg41 ,w4 long4 #a deg41 nearly #ad1jjj feet above the ,mare ,imbrium4 ,the ,silberschlag ,range1 running from near the ,s4,e4 side of ,julius ,caesar to the region ,w4 of ,agrippa4 ,,second ,,quadrant4 ,the ,alps4 ,the eastern and greater portion4 ,the ,apennines4 ,nearly the whole of the range4 ,the ,carpathians4 ,the ,teneriffe ,mountains4 ,s4,e4 of ,plato4 ,highest peak1 #hjjj feet4 ,the ,straight ,range4 ,east of the last1 in ,n4 lat4 #dh deg41 ,e4 long4 #bj deg4 ,the ,harbinger ,mountains4 ,n4,w4 of ,aristarchus4 ,the ,hercynian ,mountains4 ,near the ,n4,e4 limb1 ,e4 of ,otto ,struve1 ,n4 lat4 #be deg4 ,mount ,huygens4 ,a mountain mass projecting from the escarpment of the ,apennines1 in ,n4 lat4 #bj deg41 ,e4 long4 #c deg41 one peak rising to #ah1jjj feet above the ,mare ,imbrium4 ,mount ,wolf4 ,a great square-shaped mountain mass1 near the ,s4,e4 extremity of the ,apennines1 in ,n4 lat4 #ag deg41 ,e4 long4 #i deg41 the loftiest peak rising to nearly #ab1jjj feet above the ,mare ,imbrium4 ,eratosthenes ,i and ,x4 ,two isolated mountains ,n4 of this formation1 in ,n4 lat4 #bj deg42 ,x is #ahjj feet in height4 ,pico4 ,a magnificent isolated mountain1 ,s4 of ,plato1 in ,n4 lat4 #de deg41 ,e4 long4 #i deg41 rising some #hjjj feet above the ,mare ,imbrium4 ,pico ,b4 ,a triple-peaked mountain a few miles ,s4 of ,pico4 ,piton4 ,a bright isolated mountain #gjjj feet high1 in ,n4 lat4 #a deg41 ,e4 long4 #a deg4 ,fontinelle ,a4 ,a conspicuous isolated mountain about #cjjj feet high1 ,s4 of ,fontinelle4 ,archimedes ,z4 ,a triangular-shaped group ,e4 of ,archimedes1 in ,n4 lat4 #ca deg41 ,e4 long4 #h deg41 the highest of the peaks rising more than #bjjj feet4 ,caroline ,herschel4 ,e4 of this formation is a double-peaked mountain rising to #acjj feet4 ,gruithuisen delta and gamma4 ,on the ,n4 of this bright crater1 in ,n4 lat4 #cf deg41 ,e4 long4 #dj deg41 rises a fine mountain1 delta1 nearly #fjjj feet in height1 and on the ,n4,e4 of it the larger mass gamma1 almost as lofty4 ,mairan4 ,there is a group of three bright little mountains1 the loftiest about #hjj feet above the ,mare1 some distance ,e4 of this formation4 ,euler beta4 ,a fine but small mountain group1 more than #cfjj feet high1 on the ,mare ,imbrium1 ,s4,e4 of ,euler4 ,the ,laplace ,promontory4 ,a magnificent headland on the ,n4 side of the ,sinus ,iridum1 rising about #ijjj feet above the latter1 and about #gjjj feet above the ,mare ,imbrium4 ,cape ,heraclides4 ,a fine but less prominent headland on the opposite side of the bay1 rising more than #djjj feet above it4 ,lahire4 ,a large bright isolated mountain in the ,mare ,imbrium1 ,n4,e4 of ,lambert1 in ,n4 lat4 #bg deg41 ,e4 long4 #be deg4 ,it is1 according to ,schroter1 nearly #ejjj feet high4 ,delisle beta4 ,a curious club-shaped mountain on the ,s4,e4 of this formation1 nearly #djjj feet in height4 ,pytheas beta4 ,an isolated mountain1 #ijj feet high1 in ,n4 lat4 #bj deg41 ,e4 long4 #bc deg4 ,kirch4 ,there is a small isolated hill a few miles ,n4 of this formation4 ,kirch ,,gamma4 ,a bright mountain about #gjj feet high1 in ,n4 lat4 #ci deg41 ,e4 long4 #c deg4 ,piazzi ,smyth beta4 ,a small bright isolated mountain on a ridge ,s4 of this1 is a noteworthy object under a low sun4 ,lambert ,,gamma4 ,in ,n4 lat4 #bf deg41 ,e4 long4 #ah deg42 a remarkable curved mountain about #cjjj feet in height1 a brilliant object under a low sun4 ,d',alembert ,mountains4 ,a range on the ,e4 limb running ,s4 from ,n4 lat4 #ab deg4 ,wollaston4 ,an isolated triangular mountain about midway between this and ,wollaston ,b4 ,,third ,,quadrant4 ,the ,riphaean ,mountains4 ,an isolated range ,s4 of ,landsberg in ,s4 lat4 #g deg41 ,e4 long4 #bh deg4 ,they run in a meridional direction1 and rise at one peak to nearly #cjjj feet above the ,oceanus ,procellarum4 ,the ,percy ,mountains extend from the eastern flank of ,gassendi towards ,mersenius1 forming the north-eastern border of the ,mare ,humorum4 ,prom4 ,aenarium4 ,a steep bluff situated at the northern end of a plateau1 some distance ,e4 of ,arzachel1 in ,s4 lat4 #ah deg41 ,e4 long4 #i deg4 ,it rises some #bjjj feet above the ,mare ,nubium4 ,euclides zeta and chi4 ,two mountain masses ,n4 of this formation in ,s4 lat4 #e deg42 zeta rises about #agjj feet above the ,mare2 both are evidently offshoots from the ,riphaean range4 ,landsberg ,h4 ,an isolated hill in ,s4 lat4 #d deg41 ,e4 long4 #be deg4 ,nicollet ,c4 ,s4,e4 of ,nicollet1 in ,s4 lat4 #bb deg41 ,e4 long4 #ag deg42 is hemmed in by a mountain mass rising to more than #bjjj feet above the ,mare ,nubium4 ,the ,stag's-,horn ,mountains4 ,at the ,s4 end of the straight wall1 or railroad1 in ,s4 lat4 #bd deg41 ,e4 long4 #h deg41 a curious mountain mass rising about #bjjj feet above the ,mare ,nubium4 ,lacroix delta4 ,a mountain more than #gjjj feet high1 ,n4 of ,lacroix4 ,flamsteed ,e4 ,a mountain of more than #cjjj feet in ,s4 lat4 #d deg41 ,e4 long4 #ea deg4 ,d',alembert ,mountains4 ,a very lofty range on the ,e4 limb1 extending to ,s4 lat4 #aa deg4 ,the ,cordilleras4 ,close to the ,e4 limb2 they lie between ,s4 lat4 #h deg4 and ,s4 lat4 #bc deg4 ,rook ,mountains4 ,on the ,e4 limb1 extending from about ,s4 lat4 #ah deg4 to ,s4 lat4 #ce deg4 ,according to ,schroter1 they attain a height of #be1jjj feet4 ,dorfel ,mountains4 ,on the ,s4,e4 limb between ,s4 lat4 #eg deg4 and ,s4 lat4 #hj deg4 ,leibnitz ,mountains4 ,on the ,s4 limb extending ,w4 from ,s4 lat4 #hj deg4 beyond the ,pole on to the ,fourth ,quadrant4 ,perhaps the loftiest range on the limb4 ,madler's measures give more than #bg1jjj feet as the height of one peak1 and there are several others nearly as high4 ,,fourth ,,quadrant4 ,the ,altai ,mountains4 ,a fine conspicuous serpentine range1 extending from the ,e4 side of ,piccolomini in a north-easterly direction to the region between ,tacitus and ,catherina1 a length of about #bge miles4 ,the loftiest peak is over #ac1jjj feet4 ,the average height of the southern portion is about #fjjj feet4 ,the region lying on the ,s4,e4 of this range is a vast tableland1 devoid of prominent objects1 rising gradually towards the mountains1 which shelve rapidly down to an equally barren expanse on the ,n4,w4 ,the ,pyrenees4 ,these mountains1 on the ,e4 of ,guttemberg1 border the western side of the ,mare ,nectaris4 ,their loftiest peak1 rising nearly to #ab1jjj feet1 is on the ,s4,e4 of ,guttemberg4 ,,list ,,of ,,the ,,principal ,,ray-,,systems1 ,,light-,,surrounded ,,craters1 ,,and ,,light- ,,spots4 ,in this list1 which does claim to be exhaustive1 most of the objects noted by ,schmidt are incorporated4 ,,first ,,quadrant4 ,autolycus4 ,encircled by a delicate nimbus1 throwing out four or five prominent rays extending towards ,archimedes4 ,seen best under evening illumination4 ,aristillus4 ,the centre of a noteworthy system of delicate rays extending ,w4 towards the ,caucasus2 and on the ,s4 disappearing among the rays of ,autolycus4 ,they are traceable on the ,mare ,nubium near ,kirch4 ,theaetetus4 ,a very brilliant group of little hills ,e4 of this formation4 ,eudoxus ,a4 ,a light-surrounded crater ,w4 of ,eudoxus1 with distinct long streaks1 one of which extends to the ,s4 wall of ,aristoteles4 ,aristoteles ,a4 ,a light-surrounded crater in the ,mare ,frigoris1 ,n4,e4 of ,aristoteles4 ,aratus4 ,a very conspicuously brilliant crater in the ,apennines1 with a smaller light-surrounded crater ,w4 of it4 ,sulpicius ,gallus4 ,a light spot near4 ,manilius4 ,surrounded by a light halo and streaks4 ,taquet4 ,has a prominent nimbus1 and indications of very delicate streaks4 ,plinius ,a4 ,is surrounded by a well-marked halo4 ,posidonius gamma4 ,among the hills ,e4 of this formation a light spot resembling ,linne1 according to ,schmidt4 ,he first saw it in #ahfg1 when it had a delicate black spot in the centre4 ,dr4 ,vogel observed and drew it in #ahga with the great refractor at ,bothkamp4 ,these observations were confirmed by ,schmidt in #ahge with the #ad-;feet refractor at ,berlin4 ,littrow4 ,a very bright light-spot with streaks1 on the site of a little crater and well-known cleft ,e4 of this ring-plain4 ,romer4 ,a light-surrounded mountain on the ,e4 ,macrobius4 ,two light-surrounded craters on the ,e4 of this formation1 the more northerly being the brighter4 ,cleomedes ,a4 7,on the floor47 ,surrounded by a nimbus and rays4 ,large crater1 ,a1 on the ,e4 has also a nimbus and rays4 ,agrippa4 ,exhibits faint rays4 ,godin4 ,exhibits faint rays4 ,proclus4 ,a well-known ray-centre1 some of the rays prominent on part of the ,mare ,crisium4 ,taruntius4 ,has a very faint nimbus1 with rays1 on a dark surface4 ,dionysius4 ,a brilliant crater with a prominent1 bright1 excentrically placed nimbus on a dark surface1 on which distinct rays are displayed4 ,hypatia ,b4 ,a very small bright crater on a dark surface3 surrounded by a faint nimbus4 ,apollonius4 ,among the hills ,s4 of this1 there is a small bright streak system4 ,eimmart4 ,there is a large white spot ,n4,w4 of this4 ,geminus is associated with a system of very delicate rays4 ,menelaus4 ,a brilliant object4 ,it is traversed by a long ray from ,tycho4 ,,second ,,quadrant4 ,anaxagoras4 ,the centre of an important ray-system4 ,timocharis is surrounded by a pale irregular nimbus and faint rays1 most prominently developed on the ,w4 side of the formation4 ,copernicus4 ,next to ,tycho1 the most extended ray-centre on the visible surface4 ,some distance on the ,e41 in ,e4 long4 #be deg41 ,n4 lat4 #aa deg41 lies a very small but conspicuous system1 and in ,e4 long4 #bb deg41 ,n4 lat4 #h deg4 a bright light spot among little hills4 ,gambart ,a4 ,a bright crater with large nimbus and rays4 ,landsberg ,a4 ,a light-surrounded crater on a dark surface1 with companions1 referred to under the ,third ,quadrant4 ,encke4 ,there is a light-surrounded crater ,s4 of this4 ,kepler4 ,a noted ray-centre4 ,it is surrounded by an extensive halo1 especially well developed on the ,e41 across the ,mare ,procellarum4 ,bessarion4 ,two bright craters3 the more northerly is prominently light-surrounded1 while its companion is less conspicuously so4 ,aristarchus4--,the most conspicuous bright centre on the moon1 the origin of a complicated ray-system4 ,delisle4 ,s4 of this formation there is a tolerably bright spot on the site of some hills4 ,timaeus4 ,a ray-centre4 ,euler4 ,feeble halo with streaks4 ,galileo4 ,between this and ,reiner is a curious bright formation with short rays1 referred to in the ,catalogue1 under ,reiner4 ,cavalerius4 ,a light streak originating in the ,w4 wall1 and extending on to the ,oceanus ,procellarum4 ,olbers4 ,a considerable ray-system1 but seldom distinctly visible4 ,lichtenberg4 ,faintly light-surrounded4 ,,third ,,quadrant4 ,tycho4 ,the largest and best known system on the visible surface4 ,zuchius4 ,a remarkable ray-system1 but one which is only well seen when libration is favourable4 ,bailly4 ,n4 of the centre of this great enclosure are two very distinct radiating streaks4 ,schickard4 ,four conspicuous light spots1 probably craters1 on the ,s4,e4 ,byrgius ,a4 ,a brilliant ray-centre1 most of the rays trending eastward from a nimbus4 ,hainzel4 ,there are several bright spots ,e4 of this formation4 ,mersenius4 ,two or three light-rays originate from a point on the ,w4 rampart4 ,mersenius ,c4 ,a light-surrounded crater with short rays4 ,grimaldi4 ,there are three bright spots on the ,w4 wall4 ,damoiseau4 ,a light-surrounded crater ,w4 of ,damoiseau1 ,e4 long4 #eh deg41 ,s4 lat4 #f deg4 ,flamsteed ,c4 ,a light-surrounded crater on a dark surface4 ,lubieniezky ,a4 ,crater with halo on a dark surface4 ,lubieniezky ,f4 ,crater with halo on a dark surface4 ,lubieniezky ,g4 ,crater with halo on a dark surface4 ,birt a4 ,a light-surrounded crater4 ,landsberg4 ,e4 of ,landsberg1 four light-surrounded craters1 forming with ,landsberg ,a 7in the ,second ,quadrant7 an interesting group4 ,lohrmann ,a4 ,a light-surrounded crater1 with a light area a few miles ,n4 of it4 ,s4 lat4 #a deg41 ,e4 long4 #fa deg4 ,euclides4 ,has a conspicuous nimbus with traces of rays1 a typical example4 ,guerike4 ,there is a crater1 with nimbus1 ,w4 of this1 in ,e4 long4 #ab deg41 ,s4 lat4 #aa deg4 #e min4 ,parry4 ,a very brilliant light-spot in the ,s4 wall4 ,parry ,a4 ,surrounded by a bright nimbus4 ,alpetragius ,b4 ,a conspicuous light-surrounded crater1 one of the most remarkable on the moon4 ,alpetragius d 7,e4 long4 #aa deg41 ,s4 lat4 #ac deg4 #h min474 ,a bright spot1 seen by ,madler as a crater1 but which1 as ,schmidt found in #ahfh1 no longer answers to this description4 ,mosting ,c4 ,a light-surrounded crater4 ,lalande4 ,has a large nimbus and distinct rays4 ,hell4 ,a large ill-defined spot in ,e4 long4 #d deg41 ,s4 lat4 #cc deg4 ,this is most probably the site of the white cloud seen by ,cassini4 ,mercator4 ,there is a brilliant crater and light area under ,e4 wall4 ,,fourth ,,quadrant4 ,stevinus a4 ,a crater ,e4 of ,stevinus2 it is a centre of wide extending rays4 ,furnerius ,a4 ,prominently light-surrounded1 with bright streaks1 radiating for a long distance ,n4 and ,s4 ,messier ,a4 ,the well-known ,comet rays1 extending ,e4 of this4 ,langrenus4 ,has a large but very pale ray-system4 ,it is best seen under a low evening sun4 ,three long streaks radiate towards the ,e4 from the foot of the glacis of the ,s4,e4 wall4 ,censorinus4 ,a very brilliant crater with faint rays4 ,theophilus4 ,the central mountain is faintly light-surrounded4 ,madler4 ,this ring-plain and the neighbourhood on the ,n4 and ,n4,w41 include many bright areas and curious streaks4 ,almanon4 ,about midway between this and ,argelander is a very brilliant little crater4 ,beaumont4 ,between this and ,cyrillus stand three considerable craters with nimbi4 ,cyrillus ,a4 ,a prominent light-surrounded crater4 ,alfraganus4 ,a light-surrounded crater with rays4 ,,position ,,of ,,the ,,lunar ,,terminator ,though the position of the ,lunar ,terminator is given for mean midnight throughout the year in that very useful publication the ,companion to the ,observatory1 it is frequently important in examining or comparing former drawings and observations to ascertain its position at the times when they were made4 ,for this purpose the subjoined tables 7which first appeared in the ,selenographical ,journal7 will be found useful1 as they give for any day between ,a4,d4 #aghj and ,a4,d4 #aijj the selenographical longitude of the point where the terminator crosses the moon's equator1 which it does very nearly at right angles4 ,tables and examples ,,lunar ,,elements ,moon's mean apparent diameter - #ca min4 #h sec4 ,moon's maximum apparent diameter - #cc min4 #cc4bj sec4 ,moon's minimum apparent diameter - #bi min4 #bc4fe sec4 ,moon's diameter1 in miles - #bafc miles4 ,volume 7earth's #a7 - #a_/di4bj or #j4jbjcc4 ,mass 7earth's #a7 - #a_/ha4dj or #j4jabh4 ,density 7earth's #a7 - #j4fjdai1 or #c4ddd the density of water 7water being unity74 ,surface area1 about #ad1fjj1jjj square miles 7earth's surface area1 #aif1hgj1jjj miles7 ,earth's surface area #a1 moon's - ,about #b_/bg or #j4jgdjg4 ,action of gravity at surface - #j4afdhi or #a_/f4jfe of the earth's4 ,surface of moon never seen - #j4dajj4 ,surface of moon seen at one time or another - #j4eijj4 ,synodical revolution1 or interval from new moon to new moon 7commonly called a lunation7 - #bi d4 #ab h4 #dd m4 #b4fhd s4 - #bi4ecjehhg days4 ,sidereal revolution1 or time taken in passing from one star to the same star again - #bg d4 #g h4 #dc m4 #aa4ede s4 - #bg4cbaffad days4 ,tropical revolution1 or time taken in passing from the first point of ,aries to the same point again - #bg d4 #g h4 #dc m4 #d4fh s4 - #bg4cbaehb days4 ,anomalistic revolution1 or time taken in passing from perigee to perigee - #bg d4 #ac h4 #ah m4 #cg4dd s4 - #bg4eedfj days4 ,nodical revolution1 or time taken in passing from rising node to rising node - #bg d4 #e;h4 #em4 #ce4ha s4 - #bg4babbb days4 ,distance 7mean7 in terms of the equatorial radius of the earth - #fj4bg4 ,distance in miles 7mean7 - #bch1hdj miles4 ,distance1 maximum - #beb1igb miles4 ,distance1 minimum - #bba1fad miles4 ,mean excentricity of moon's orbit - #j4jedijhjg4 ,inclination of moon's orbit to the ecliptic 7mean7 - #e deg4 #h min4 #ci4if sec4 ,inclination of moon's axis to the ecliptic - #hg deg4 #bg min4 #ea sec4 ,inclination of moon's equator to the ecliptic - #a deg4 #cb min4 #i sec4 ,maximum libration in latitude - #f deg4 #dd min4 ,maximum libration in longitude - #g deg4 #de min4 ,maximum total libration from earth's centre - #aj deg4 #af min4 ,maximum diurnal libration - #a deg4 #a min4 #bh4h sec4 ,angle subtended by one degree of selenographical latitude and longitude at the centre of the moon's disc1 when at its mean distance - #af4eff sec4 ,length of a degree under these conditions - #ah4hga miles4 ,selenographical arc at the centre of the moon's surface1 subtending an angle of one second of arc - #c min4 #cg4ca sec4 ,miles at the centre of the moon's disc1 subtending an angle of one second of arc - #a4aci ,it must be remembered that this value is increased1 in departing from the centre1 in the proportion of the secants of the angular distance from the centre4 ,period of similar phase - #ei d4 #a;h4 #bhm4 #b lunations4 ,or1 more accurately - #ddb d4 #bc h4 #ae lunations4