,,gas ,,burners ,,old ,,and ,,new4 ,,gas ,,burners ,,old ,,and ,,new4 ,a ,historical and ,descriptive ,treatise ,,on ,,the ,,progress ,,of ,,invention ,,in ,,gas ,,lighting2 ,,embracing ,,an ,,account ,,of ,,the ,,theory ,,of ,,luminous ,,combustion4 ,,by ,,owen ,,merriman4 ,reprinted from the ,,journal ,,of ,,gas ,,lighting4 ,london3 ,,walter ,,king1 #aa1 ,,bolt ,,court1 ,,fleet ,,street1 ,e4 ,c4 #ahhd4 ,w4 ,,king ,,and ,,sell1 ,,printers1 #ab1 ,,gough ,,square1 ,,fleet ,,street1 ,,london4 ,transcriber's ,note3 ,figure #aa and ,figure #ab are identical4 ,,preface4 ,the little work here presented to the public appeared originally in the pages of the ,journal of ,gas ,lighting4 ,in the hope that it may thereby become of service to a wider circle of readers1 it has been revised and done into its present shape4 ,the object of the writer will be attained if it is the means of lessening1 in any degree1 the suspicion and prejudice 7born of ignorance7 which1 alas6 yet prevail with regard to gas and gas lighting4 ,,contents4 ,,page ,,introduction #i ,,the ,,first ,,gas-,,burner #ac ,,the ,,batswing ,,burner #ae ,,the ,,union-,,jet ,,or ,,fishtail ,,burner #ag ,,how ,,light ,,is ,,produced ,,from ,,coal ,,gas #bj ,,improvements ,,in ,,flat-,,flame ,,burners #be ,b,r,oe,n,n,e,r',s ,,burners #ca ,,the ,,hollow-,,top ,,burner #ce ,,bray',s ,,burners #ch ,,argand ,,burners #dd ,,sugg',s ,,argands #dh ,,the ,,douglass ,,burner #eb ,,governor ,,burners #ee ,,regenerative ,,burners #fa ,,incandescent ,,burners #gc ,,conclusion #gi ,,chapter ,i4 ,,introduction4 ,sidenote3 ,gas consumers and gas producers4 ,the subject of gas-burners and the development of light from coal gas is of considerable interest1 alike to the consumer and the producer of gas4 ,when it is known that one burner may develop twice as much light as another1 for the same consumption of gas--the first cost of the one being no higher than that of the other--its importance to the former will scarcely be disputed4 ,to the gas consumer it is obviously of great value to know how he may most effectively and economically develop the illuminating power of the gas which is supplied to him2 and so obtain the fullest return1 in lighting effect1 for the money which he expends4 ,not quite so obvious is its relation to the latter4 ,to a person totally unacquainted with the recent history of gas lighting1 and ignorant of the policy which has guided the most prosperous gas undertakings to their successful issues1 it may appear that the manufacturer of gas is not closely concerned with the utilization of the commodity which he supplies4 ,such an one might argue1 and with a certain show of reason1 that the sole business of the gas maker is with its production2 that after providing1 in the consumer's service-pipe1 a full and continuous supply of gas1 of the stipulated quality1 his care ends2 and that henceforth the utilization and management of the illuminant rests with the consumer himself4 ,but1 by any one who is at all conversant with the subject1 it will be readily conceded that the interest of the manufacturer of gas1 in this matter1 is only second to that of the consumer4 ,in the gas industry1 as in any other business undertaking1 the concern prospers or declines according as the interests of the customers are considered or neglected4 ,this has been conclusively demonstrated in the history of many gas undertakings4 ,so long as their management was conducted in exclusive and selfish regard solely to their own internal affairs--looking with supreme indifference or careless apathy upon the needs of the consumers--so long was their career marked by difficulties and embarrassments4 ,no sooner1 however1 were the claims of the consumers recognized1 and efforts put forth to further their interests1 than the prospects of the concern brightened2 and by adhering to1 and extending the same line of action1 the goal of commercial prosperity was eventually reached4 ,seeing1 therefore1 that the subject is of so supreme importance to consumers of gas1 and that the interests of the consumer are closely interwoven with those of the manufacturer1 it is eminently desirable that there should be more generally diffused a correct knowledge of the principles of economical gas consumption1 and of the extent to which these principles are applied in the various burners which1 from time to time1 have been invented4 ,no further apology ought therefore to be required in presenting to the reader the following disquisition on gas-burners4 ,it may1 however1 be of advantage for me to state in brief1 at the commencement1 what are the objects ,i have in view1 and what the chief considerations which have led me to write this treatise4 ,sidenote3 ,waste of gas4 ,i purpose1 then1 to tell of the progress that has been made in apparatus for the development of light from coal gas2 to relate how the crude and imperfect devices of the early inventors have been gradually improved upon2 and1 while not ignoring the drawbacks connected with recently invented burners1 or the defects inherent to their construction1 to show1 in the superior achievements of these burners1 how great an advance has been made upon the apparatus formerly in use4 ,it will be1 also1 my endeavour to make plain the little understood phenomenon of the production of light by the combustion of coal gas2 and to show the extent to which the illuminating power developed is dependent upon the burner employed4 ,that there is need for such information as ,i propose to furnish must be sufficiently obvious to any one who has considered the waste of gas which takes place through ignorance of the laws of its combustion1 and through the use of defective burners4 ,in a report presented to the ,board of ,trade by the ,london ,gas ,referees in #ahga1 it was stated that a number of burners had been tested1 taken from various places of business in the ,metropolis2 the major portion of which gave out only one-half1 and some of them not more than one-fourth1 of the illuminating power capable of being developed from the gas4 ,although1 since the time that report was penned1 considerable progress has been made in the construction of burners1 and in the more general adoption of efficient burners by the public1 much yet remains to be done4 ,doubtless it would still be within the mark to assert that fully one-fifth of the gas consumed by the public might be saved by the adoption of better burners1 and by the observance of the conditions necessary for their satisfactory operation2 and when it is borne in mind that the gas-rental of the ,united ,kingdom amounts to a sum of certainly not less than ,l#i1jjj1jjj per annum1 the saving which might be effected assumes truly great proportions4 ,the field on which ,i propose to enter can hardly be said to be already occupied4 ,nowhere that ,i know of is the subject of gas-burners fully treated of in a manner available for the general reader4 ,with the exception of the admirable chapter contributed by ,mr4 ,r4 ,h4 ,patterson to ,king's ,treatise on ,coal ,gas1 ,i am not aware that the subject has been dealt with to any complete extent by recent writers4 ,but1 admirable as is that contribution to the literature of the subject1 being written for technical readers1 it is neither so popular in style nor so elementary in character as to fulfil the purpose which ,i have in view in writing the present series of articles4 ,briefly stated1 my sole purpose is to make the subject of the combustion of gas for the production of light intelligible to the simplest2 and to present an interesting account of the progress of invention in the perfection of gas-burners4 ,while passing lightly over many modifications of apparatus which have been of but limited or temporary service1 ,i shall not scruple to dwell at length upon such burners as have done much to further the extension of gas lighting1 or whose construction exhibits a considerable advance upon previous attainments4 ,and while it will be my endeavour to clothe my remarks in such language as shall be understanded of the people1 in speaking of the theory of combustion ,i hope to be sufficiently explicit to enable my readers to form a clear conception of the scientific principles underlying the phenomena of which ,i treat4 ,sidenote3 ,progress of gas lighting4 ,a further justification--if such1 indeed1 were needed--for the appearance of this treatise might be found in the remarkable impetus which has been given1 within recent years1 to the perfection of the details of gas manufacture and the improvement of gas-burners4 ,of course1 ,i refer to the beneficial consequences to the gas industry which have followed the brief1 if conspicuous1 career of electricity as an illuminating agent4 ,that the interest in improved illumination which has been aroused by the short-lived popularity of the electric light1 and the extravagant claims put forward on its behalf1 have stimulated to the development of the resources of gas lighting1 is sufficiently obvious to the most superficial observer4 ,and not only has the manufacturer of gas been benefited1 but the public have reaped no inconsiderable advantage4 ,at the present day1 gas is sold at a far cheaper rate1 as well as of a higher quality1 than at any former period4 ,nor is the advent of cheap gas the only direction in which the public have gained4 ,although not so patent to the majority1 the improvements that have been effected in the methods of burning gas1 so as to obtain the fullest advantage from its use1 are calculated to confer benefits equally real1 and not less valuable4 ,it is hardly too much to say that the last few years have witnessed a greater advance in the apparatus employed in the combustion of gas than had been effected during the whole previous history of gas lighting4 ,this being so1 it may not be unacceptable if ,i attempt to pass in review some of the various burners that have been invented and used for obtaining light from coal gas2 showing the successive improvements that are exhibited in their construction1 and the extent to which they apply the principles of combustion4 ,it may be that what ,i have to relate will awaken some minds to the consciousness that gas lighting has not altogether retired into obscurity on the advent of electricity--nay1 that it has even assumed a bolder front2 and1 with increased resources and accession of strength1 is prepared firmly to maintain its position as at once the most convenient1 economical1 and reliable of artificial illuminants4 ,,chapter ,,ii4 ,,flat-,,flame ,,burners4 ,,the ,,first ,,gas-,,burner4 ,the first gas-burner was a very simple and unpretentious contrivance4 ,in one of the earliest works on gas lighting#a we read3 ,the extremities of the pipes have small apertures1 out of which the gas issues2 and the streams of gas1 being lighted at those apertures1 burn with a clear and steady flame as long as the supply of gas continues4 ,familiar as it is to us1 and from its familiarity unnoticed1 the phenomenon presented by the flame thus produced continuing to burn as long as the supply of gas continued1 was doubtless1 to the first experimenters1 a wonderful sight4 ,though we may smile at the question1 it is not difficult to understand the incredulity of the honourable member who1 when ,murdock was examined before a ,committee of the ,house of ,commons1 in #ahji1 asked the witness3 ,do you mean to tell us that it will be possible to have a light without a wick8 ,yes2 ,i do indeed1 replied ,murdock4 ,ah1 my friend1 replied the member1 you are trying to prove too much4 #a ,accum's ,treatise on ,gas-,lights4 ,third edition1 #ahaf4 ,sidenote3 ,the dawn of gas lighting4 ,it was but natural1 seeing that oil-lamps and candles were the only forms of artificial illumination in use prior to the introduction of gas lighting1 that the earliest attempts at illumination by gas should be in imitation of the effects produced by those means4 ,accordingly we find that one of the first gas-burners employed was the ,argand1 modelled upon the oil-lamp of that name1 which had been found to give superior results2 while in more general use1 and for some time almost the sole apparatus available1 were single jets1 giving a flame similar in appearance to that of a common candle1 together with various combinations of these jets4 ,a fair idea of the mode of illumination practised during the earliest period of gas lighting may be gleaned from the following extract from a paper describing the lighting of ,messrs4 ,phillips and ,lee's cotton-mill at ,manchester1 read before the ,royal ,society1 in #ahjh1 by ,mr4 ,william ,murdock3-- ,the gas-burners are of two kinds4 ,the one is upon the principle of the ,argand lamp1 and resembles it in appearance2 the other is a small curved tube with a conical end1 having three circular apertures or perforations1 of about #a-cjth of an inch in diameter1 one at the point of the cone1 and two lateral ones1 through which the gas issues1 forming three divergent jets of flame1 somewhat like a fleur-de-lis4 ,the shape and general appearance of this tube has procured for it1 among the workmen1 the name of the cockspur burner4 ,illustration3 ,,fig4 #a4--;,,early ,,gas-,,burners4 7,from ,accum's ,treatise on ,gas-,lights47 ,nor was much advance made upon these arrangements down to the year #ahaf1 judging from ,accum's ,treatise 7before cited71 as the subjoined extract from that work1 together with the above illustrations1 will show3-- ,the burners are formed in various ways--either a tube ending with a simple orifice1 at which the gas issues in a stream1 and if once lighted will continue to burn with the most steady and regular light imaginable1 as long as the gas is supplied2 or two concentric tubes of brass or sheet iron are placed at a distance of a small fraction of an inch from each other1 and closed at the bottom4 ,the gas which enters between these cylinders1 when lighted1 forms an ,argand lamp1 which is supplied by an internal and external current of air in the usual manner4 ,or the two concentric tubes are closed at the top with a ring1 having small perforations1 out of which the gas can issue2 thus forming small distinct streams of light4 ,it is interesting1 in view of the present demand for increased illumination1 and for burners of high illuminating power1 to note the amount of light produced by the burners then in use4 ,in ,mr4 ,murdock's paper we find it stated that each of the ,argands in use at ,messrs4 ,phillips and ,lee's establishment gave a light equal to that of #d candles 7mould candles of #f to the pound72 and each of the cockspurs a light equal to #b-a_/d of the same candles4 ,from which meagre results we conclude that1 besides being burnt in an ignorant and wasteful manner1 the gas consumed was wofully deficient in illuminating power4 ,,the ,,batswing ,,burner4 ,sidenote3 ,who invented the batswing burner8 ,a notable advance was made when the batswing burner was invented4 ,to whom we are indebted for this invention seems involved in some doubt4 ,although ,clegg1 in the historical introduction to his valuable work1#b says1 very distinctly1 that the batswing burner was introduced by a ,mr4 ,stone1 an intelligent workman employed by ,mr4 ,winsor1 it is not so much as mentioned by ,accum1 even in the third edition of his ,treatise2 and ,accum1 it may be remarked1 was for some time closely associated with ,winsor in the promotion of the latter's ambitious and visionary schemes4 ,yet1 if ,clegg's statement be correct1 it would almost appear to fix the date of the introduction of this burner as prior to #ahaf4 ,but to whomsoever is due the credit of its invention1 certain is it that the batswing burner was a considerable improvement upon the old cockspur4 ,producing a better light for the gas consumed1 it assisted to demonstrate still further the superiority of gas lighting over other methods of illumination2 and as it could be supplied at a trifling cost1 and contained no delicately adjusted nor easily injured parts1 it enabled the benefits of the new method of lighting to be extended to wherever artificial light was required4 #b ,clegg's ,treatise on ,coal ,gas1 #ahda1 p4 #ba4 ,illustration3 ,,fig4 #b4--;,,batswing ,,burner4 ,sidenote3 ,superiority of the batswing over the cockspur burner4 ,from the cockspur and single jet burners the gas ascended in streams1 rising into the air until it came in contact with sufficient oxygen to completely consume it4 ,in order that this might take place without producing a flame of an inordinate length1 and without much smoke1 the orifices were restricted to a very small size2 and the gas issuing from these at considerable pressure tended to draw in1 and mix with the air in its course4 ,besides the loss of illuminating power caused by this mixture of air with the gas flame 7similar to what takes place in a ,bunsen burner71 the cooling influence upon the small body of flame of the mass of metal composing the burner1 operated still further to reduce the quantity of light which the gas was calculated to yield4 ,with the batswing the gas was spread out producing1 when ignited1 a thin sheet of flame1 by which means the gas was enabled to combine more readily with the air necessary to effect complete combustion4 ,the size of the flame being1 in comparison with that of the cockspur1 so much larger proportionately to the metal burner1 the cooling effect of the latter was not so apparent4 ,the increased size of flame1 also1 of itself1 tended to improve the illuminating power2 each portion of flame contributing to elevate and sustain the temperature of the whole1 and so to heighten the intensity of incandescence to which the light-giving particles were raised4 ,sidenote3 ,batswing and ,argand burners compared4 ,even with the ,argands of that day1 the batswing compared not unfavourably4 ,the former burner1 having the regulation of its air supply under complete control1 gives the best results when the gas is supplied to it at a low pressure2 as then the requisite quantity of air to ensure complete combustion of the gas can be delicately adjusted by means of a chimney of suitable length4 ,when the gas and air have been nicely adjusted to each other1 the flame becomes extremely sensitive to any change of pressure in the gas supply2 a diminution of the supply1 by reducing the quantity of gas issuing from the burner without at the same time proportionately diminishing the supply of air1 tends to destroy the illuminating power by the cooling action of the surplus air2 while an increased pressure1 by allowing more gas to issue than the air can consume1 causes the flame to smoke4 ,but at the time to which ,i now refer the principles of combustion were little understood1 still less applied in the construction of burners4 ,besides this1 the pressure of the gas in the mains was excessive2 and there being no method adopted of controlling it at the burner1 the construction of a good ,argand was1 under the circumstances1 almost impossible4 ,the batswing was not so prejudicially affected by an excess of pressure4 ,pressure to some extent was1 indeed1 required to enable the flame to attain its normal shape2 while any excess forced the gas through the flame without permitting it to be raised to incandescence before being consumed1 and although necessitating loss of light1 caused no inconvenience like a smoking flame4 ,another important advantage which the batswing possessed over the ,argand burner was its simplicity of construction2 and the absence of accessories1 such as the glass chimney--dispensing with the cleaning and attention which the latter required4 ,had the benefits of gas lighting been dependent upon the use of apparatus so fragile1 and requiring so much care and attention as the ,argand1 the range of its applicability must have been considerably limited1 and its prospects of commercial success much less assured4 ,the introduction of a series of cheap but effective burners1 however1 altered the conditions of gas lighting1 and marked the commencement of a new era in artificial illumination4 ,the possibility of obtaining1 by means of a burner so simple and apparently insignificant as the batswing1 results little1 if at all1 inferior to what could be obtained by the use of the most complicated and expensive1 was of advantage alike to the consumer and the producer of gas4 ,to the former it gave the benefits of an increased illumination1 without requiring any corresponding outlay2 to the latter it promised a growing extension of the use of coal gas1 and thus furnished the surest guarantee of future progress and prosperity4 ,,the ,,union-,,jet1 ,,or ,,fishtail ,,burner4 ,sidenote3 ,who invented the union-jet burner8 ,the batswing had been for some years in extensive use before a burner was produced worthy in any degree to compare with it in respect to simplicity and efficiency4 ,the invention of the union-jet1 or fishtail burner1 furnished a competitor equally simple2 little1 if at all1 inferior as regards efficiency2 and1 to some extent1 superior to the former burner in general adaptability4 ,although so much behind in point of time1 the new burner speedily rivalled the older batswing in popular favour2 and in its various modifications and improvements may be said1 without fear of contradiction1 to have received a wider application than any other gas-burner4 ,as in the case of the batswing1 so with regard to this burner3 few details are recorded of its invention4 ,but1 slight as is the information available1 such as we have is more satisfactory and more authentic than the meagre notice of ,clegg1 which is all that is known of the invention of the former burner4 ,it appears to be established beyond doubt that the union-jet is the joint invention of ,mr4 ,james ,b4 ,neilson1 the inventor of the hot-blast1 and ,mr4 ,james ,milne1 of ,glasgow1 founder of the engineering firm of ,milne and ,son4 ,about the year #ahbj1 or soon after 7as in that year ,mr4 ,neilson was appointed ,manager of the ,glasgow ,gas-,works71 these gentlemen were experimenting with gas-burners1 when they discovered that by allowing two jets of gas1 of equal size1 to impinge upon each other at a certain angle1 a flat-flame was produced1 with increased light4 ,this was the origin of the union-jet2 so called from the manner in which the flame is produced4 ,at first separate nipples were employed for the two jets2 but1 very soon1 ,mr4 ,milne hit upon the expedient of drilling two holes1 at the required angle1 in the same nipple4 ,in this manner1 with slight modifications1 the burner has continued to be constructed down to the present day4 ,illustration3 ,,fig4 #c4--;,,fishtail ,,burner4 ,the explanation of the preference accorded to this burner over its predecessor1 the batswing1 is to be found chiefly1 ,i think1 in the very different shapes of the respective flames produced by the two burners4 ,the batswing1 in its original form1 produced a flame of great width1 but of no corresponding height4 ,the extremities of the flame1 stretching out from the burner so far on either hand1 were easily affected by an agitation of1 or commotion in the surrounding atmosphere2 a slight draught or current of air causing the flame to smoke at these points4 ,the extreme width of flame also precluded the use of this burner in globes4 ,the flame produced by the union-jet burner1 as first constructed1 was very different to the one just described4 ,longer than that of the batswing1 and considerably narrower 7but widening gradually from its base1 at the burner1 to its apex71 it presented somewhat nearly the appearance of an isosceles triangle2 or more closely1 perhaps 7with its slightly-forked apex71 the tail of a fish1 from which resemblance it is commonly designated the fishtail burner4 ,this form of flame was better adapted for use in globes1 and also better withstood the effects of draughts4 ,and it is perhaps not unreasonable to suppose that as in shape it approached more closely to the kind of flame with which the people had been familiar in oil lamps1 the flame produced by the union-jet burner was more agreeable to the eye than that of the batswing1 and that this seemingly trivial consideration will account1 to some extent at least1 for the undue favour shown towards it4 ,for it must not be assumed1 because of the widespread popularity to which the union-jet so early attained1 and which it has continued to enjoy1 that it was of necessity a better burner 7in the sense of developing more light for the gas consumed7 than the one which preceded it4 ,on the contrary1 in this regard it was not quite so effective as the batswing4 ,nor is this result surprising1 looking at the different methods adopted in the two burners for producing the same effects of light and flame4 ,sidenote3 ,union-jet and batswing burners compared4 ,from the batswing burner the gas issued in a thin but widely-extending stream1 presenting1 when ignited1 a continuous sheet of flame2 its height and width depending upon the pressure at which the gas was supplied1 but always offering an unbroken surface of flame to the air4 ,although1 from the excessive pressures which1 in the early days of gas lighting1 were generally employed1 the flame drew upon its surface too much air for the attainment of the fullest lighting efficiency obtainable from the gas2 yet the form given to the issuing stream of gas precluded the air from entering the interior of the flame1 and still further reducing its illuminating power4 ,with the union-jet burner the conditions were greatly changed2 and this latter evil1 of the introduction of cold air into the interior of the flame1 was one of the consequences entailed by the means it employed for producing its flame4 ,from this burner the gas issued in two narrow streams1 like single jets1 which1 directly after emerging from the burner1 impinged upon each other at a given angle2 the mutual shock given to the streams of gas when thus arrested causing them to spread out in a lateral direction1 and 7the high velocity at which the gas issued being expended7 to unite1 and ascend in a sluggish stream until consumed4 ,that injury to the illuminating power of the flame should result from causes connected with the manner of producing it will be understood on considering some of the phenomena associated with the production of a gas flame4 ,sidenote3 ,how air is drawn upon a gas flame4 ,when a jet or stream of gas issues into a still atmosphere1 it produces in its immediate neighbourhood1 on all sides1 an area of low pressure1 to occupy which the contiguous air rushes in4 ,induced air currents are thus set up in close proximity to1 and having the same direction as the issuing stream of gas1 and varying in force with the pressure1 or velocity1 at which the gas issues4 ,the non-luminous flame of the ,bunsen burner1 and of the so-called atmospheric burner employed in gas cooking and heating stoves 7which is produced by burning a mixture of gas and air71 is obtained by taking advantage of this tendency of a stream of gas1 issuing under pressure1 to draw air upon itself2 and it is to the same circumstance that ordinary illuminating flames owe the continuous supply of air necessary to keep up combustion4 ,for the effect is heightened when the gas is inflamed2 because1 the gaseous products of combustion being expanded by the intense heat to which they are subjected1 their velocity of ascension is vastly increased4 ,having regard to these considerations1 it will be clearly perceived how that1 in producing the flame of the union-jet burner1 the two streams of gas1 in the act of combining together1 drew into the very midst of the flame a portion of the air with which they were surrounded2 and this air1 reducing the temperature of the flame1 and diluting the illuminating gas by the inert nitrogen introduced1 as well as by its oxygen causing a too early oxidation of the carbon particles in the flame1 operated to reduce the illuminating power otherwise obtainable from the gas4 ,the foregoing remarks1 it must be borne in mind1 refer to the union-jet burner in its original form4 ,numerous improvements have been effected1 from time to time1 in its construction1 as well as in that of the batswing1 which1 by reducing its liability thus to convey air into the flame1 have increased its efficiency2 while1 at the same time1 the shape of the flame has been improved4 ,indeed1 the result of successive improvements in the construction of both burners has been so to modify the shape of their respective flames that1 in their latest and most improved form1 the flames produced by the two burners are practically identical in appearance1 although the manner of their production remains as widely diverse as at the first4 ,the improvements that led up to1 and the causes that produced this result1 will be more fully explained in the sequel4 ,,how ,,light ,,is ,,produced ,,from ,,coal ,,gas4 ,i have before remarked that1 in the early period of its use1 one of the chief obstacles to the development of the lighting power of coal gas was the excessive pressure at which it was generally supplied4 ,to understand the action of pressure in influencing the amount of light which a given quantity of gas will afford1 it is necessary to know something of the nature and properties of flame4 ,moreover1 the conditions upon which is dependent the illuminating power of a gas flame are so intimately related to each other1 that the precise functions due to each cannot well be separated from the complete effect produced by the combined operation of all4 ,i shall not1 therefore1 be needlessly digressing from my subject if1 at this juncture1 ,i explain the manner in which combustion takes place in the flame of an ordinary gas-burner4 ,in doing this1 ,i shall endeavour to clothe my remarks in very plain language2 using no more technicalities than are absolutely required by the exigencies of the subject4 ,in this way ,i hope to make my meaning clear to the simplest4 ,at the same time1 without pretending to be scientifically complete1 the explanation of the phenomena of combustion which ,i shall furnish will1 ,i trust1 be sufficiently explicit to enable the reader to form a right estimate of the principles which regulate the production of light when coal gas is consumed4 ,the end chiefly kept in view is to show clearly the extent to which the degree of light evolved is dependent upon the burner employed1 and the manner in which the gas is consumed4 ,if my remarks are the means of causing the reader to look with intelligent interest upon the familiar phenomena of gaslight1 they will not have been written altogether in vain4 ,sidenote3 ,what is coal gas8 ,seeing that this treatise is compiled especially for those whose knowledge as to what coal gas consists of is extremely limited1 it may be of advantage to preface my observations on its combustion1 and the production of light therefrom1 by a few remarks as to its composition4 ,coal gas1 as generally supplied1 is made up of a variety of distinct gases2 of which1 however1 only some three or four exist in any considerable proportion4 ,about #ej per cent41 by volume 7or half of the whole71 is hydrogen2 from #cj to #dj per cent4 consists of marsh gas2 while carbonic oxide is usually present to the extent of from #e to #ae per cent4 ,these three gases1 which constitute the great bulk of what is known as common gas--that is1 gas made from ordinary bituminous coal1 as distinguished from that produced from the more costly cannel--are of little or no value as regards the amount of light they are capable of affording4 ,the flames produced by the burning of the two former gases evolve much heat1 but are of very feeble illuminating power4 ,the latter gives a flame of a deep blue colour1 producing scarcely any light1 but1 like the other two1 an intense heat4 ,the power of coal gas to yield a luminous flame is dependent upon the small quantity of heavy hydrocarbons which it contains--a constituent1 or series of constituents1 of which common gas only contains a proportion varying between #c and #g per cent41 although in cannel gas it reaches as high as #ae or #bj per cent4 ,these heavy hydrocarbons are gases composed1 like marsh gas1 of carbon and hydrogen2 but containing in their composition1 for each unit of volume1 a greater aggregate of the two elements1 as well as a relatively higher proportion of carbon1 than exists in marsh gas4 ,one of the simplest members of the series1 and that which is usually present in by far the largest amount1 is called olefiant gas4 ,it contains twice as much carbon1 combined with only the same quantity of hydrogen1 as is contained in marsh gas4 ,but besides olefiant gas there are minute quantities of other gases of the same series1 having an analogous composition1 but differing in the amount and relative proportions they contain of the two elements of which they are composed4 ,all the gases of this series1 when properly burnt1 are capable of affording a brightly luminous flame2 but when consumed alone it is somewhat difficult1 on account of the high proportion of carbon which they contain1 to effect their combustion without the production of smoke4 ,it is1 then1 to the heavy hydrocarbons which are part of it--insignificant as their amount may appear--that the luminosity of a gas flame is solely due4 ,the other constituents which ,i have mentioned as forming so much larger a proportion of the whole1 besides contributing to the heat of the flame1 serve only to dilute these richer gases1 and so promote their more complete combustion4 ,sidenote3 ,how gas burns4 ,the various simple gases which constitute ordinary coal gas do not all burn together in the flame2 the temperature required to effect their ignition being lower for some of them than for others4 ,thus1 hydrogen is the first to burn1 taking fire readily as soon as it issues from the burner2 while the combustion of the heavy hydrocarbons does not commence until they enter the hotter portions of the flame1 and is not completed until they reach its farthest extremity4 ,neither is the process of combustion in both cases the same4 ,the former gas is at once completely consumed2 the latter first undergo decomposition by the heat of the flame1 being resolved into their elements--hydrogen and carbon--before being fully consumed4 ,this decomposition of the hydrocarbons is a factor of supreme importance in the development of the lighting power of the flame4 ,the hydrogen they contain1 being more easily ignited than the carbon1 burns first2 and the latter is set free1 in the solid form1 as minute particles of soot4 ,these particles of solid carbon1 being liberated in the midst of the flame1 are immediately subjected to its most intense heat2 they thus become white-hot before they reach the outer verge of the flame1 and come in contact with sufficient oxygen to effect their complete combustion4 ,the amount of light developed by any coal-gas flame is directly proportional to the degree of intensity to which the temperature of these carbon particles is raised1 and the length of time they remain in the flame before being finally consumed4 ,it becomes1 therefore1 a matter of considerable importance to know the conditions which are most conducive to the early liberation in the flame of free carbon1 and the attainment by it of an exalted temperature4 ,sidenote3 ,what is a gas flame8 ,looking at the flame 7say7 of a common slit burner1 it is seen to be divided into two sharply defined and wholly distinct portions4 ,first1 there is--immediately surrounding the burner head1 and extending to some distance from it--a dark1 transparent area1 which1 on closer examination1 is found to consist of unignited gas enclosed in a thin envelope of bright blue flame4 ,second1 there is 7beyond this central area7 a zone1 or belt1 of brightly luminous flame1 white and opaque2 the latter property indicating the presence of solid matter at this part of the flame4 ,that the dark central portion of the flame consists chiefly of unignited gas may be shown in various ways1 in addition to the evidence afforded by its complete transparency4 ,thus1 if a small glass tube be taken1 and its lower end inserted in the flame at this point1 the unburnt gas will pass up the tube1 and may be lighted at its upper extremity4 ,a splinter of wood thrust through this portion of the flame is charred first at the two edges of the flame2 while1 in like manner1 a piece of platinum foil remains dull in the centre of the flame1 and glows only at the points of contact with the outer air4 ,the presence of solid carbon in the luminous portion of the flame may be shown by inserting therein any cold substance 7such as a piece of metal or porcelain71 which1 reducing the temperature of the heated particles of carbon below the point at which they are consumed1 becomes instantly coated on its under surface with a deposit of soot4 ,or1 if the flame be suddenly cooled by gently blowing upon its surface1 the same result is brought about2 clouds of soot are given off1 and the flame smokes4#c #c ,the behaviour of gas flames when exposed to the action of the wind 7as exemplified in the naked lights of open markets and similar situations7 affords an instructive illustration of the theory of luminous combustion4 ,a sudden gust causes the flame to smoke1 by reducing the temperature of the liberated carbon below the point at which it can combine with the oxygen of the air4 ,a continuous wind blowing upon the flame destroys its luminosity altogether1 because the heat-intensity of the flame is lowered below the temperature necessary to decompose the hydrocarbons2 consequently1 these latter burn without the preliminary separation of carbon1 and a non-luminous flame is produced--exactly as in the ,bunsen or atmospheric burner4 ,illustration3 ,,fig4 #d4--,,showing ,,the ,,two ,,zones ,,of ,,the ,,flame1 ,,and ,,the ,,method ,,of ,,demonstrating ,,the ,,presence ,,of ,,unburnt ,,gas ,,in ,,the ,,flame4 ,sidenote3 ,how the flame is cooled4 ,the existence1 in the midst of the flame1 of an area of unconsumed gas is due to the cold gas1 as it issues from the burner1 cooling the interior of the flame below the temperature required for its ignition1 as well as to its not at once meeting with sufficient air for complete combustion4 ,the causes which affect the luminous zone of the flame are not so readily explained4 ,it has been stated that the luminosity of the flame is due to the particles of carbon1 which are separated out of the hydrocarbons in the gas1 being raised to a white heat4 ,to decompose the hydrocarbons1 a very high temperature is required2 and1 on account of the cooling effect of the stream of cold gas1 this is not attained except at some distance from the burner4 ,the abstraction of heat by the burner itself is also a cause of the reduction of the temperature of the flame2 and1 on this account1 burners of porcelain1 steatite1 or similar composition1 being bad conductors of heat1 have an advantage over those made of metal4 ,so considerable is the cooling influence of the gas stream1 that1 within certain limits1 the distance1 from the burner head1 at which the luminosity of a flame commences1 is proportionate to the velocity with which the gas issues2 or1 in other words1 the pressure at which it is delivered from the burner4 ,the effect is heightened by the tendency 7which has been before remarked7 of a stream of gas1 issuing under pressure1 to draw upon itself and mix with the surrounding air4 ,thus1 with each increment of pressure the luminous zone of the flame is farther removed1 until a point is reached at which the gas is so mixed with air before being consumed that the luminosity of the flame is completely destroyed4 ,sidenote3 ,effects of pressure in the gas supply4 ,but it must not be assumed1 because of the foregoing remarks1 that the pressure at which the gas issues from the burner is altogether an unmixed evil4 ,in flat-flame burners it fulfils the important function of promoting intensity of combustion1 by bringing the white-hot particles of carbon into intimate and rapid contact with the air that is necessary for complete combustion4 ,in ,argand burners this duty is discharged by the glass chimney2 but with flat-flame burners it devolves entirely upon the pressure at which the gas issues from the burner4 ,it will be seen1 therefore1 that the pressure of the gas is a factor of considerable importance in determining the amount of light afforded by a gas flame1 as it is a matter requiring careful adjustment with each and every burner4 ,on the one hand1 with an excessive pressure the intensity of combustion is increased2 but the separated carbon does not remain so long in the flame4 ,the area of luminosity is thereby decreased1 and the total light yielded is reduced4 ,on the other hand1 with insufficient pressure the combustion is not energetic enough to raise the particles of carbon to a white heat2 consequently1 the illuminating power of the flame is feeble1 or else the carbon escapes unconsumed as smoke4 ,the thickness of the flame produced by any burner has also an important bearing upon the degree of light afforded2 and this property of thickness1 again1 is dependent upon the width of slit1 in the case of batswings 7or1 in the case of union-jets1 upon the size of orifices71 and the pressure at which the gas is supplied4 ,the thickness of the flame yielded by any burner will obviously vary inversely with the pressure at which the gas is supplied to it4 ,with a thin flame1 all parts of the flame are so completely exposed to the air1 that the particles of carbon are no sooner raised to the temperature required to enable them to give out light than they are entirely consumed4 ,with a thicker flame the carbon separated in the midst of the flame exists for a sensibly longer period of time in the white-hot state before it reaches the outside of the flame1 and meets with sufficient oxygen for its complete combustion4 ,thus we find that the best flat-flame burners have comparatively wide orifices2 while the pressure at which the gas is delivered from the burner is carefully reduced to the lowest point at which a firm flame is obtained1 without smoke4 ,similarly1 in the best ,argands the pressure is considerably diminished within the burner1 and the gas allowed to issue gently through relatively large holes2 while the chimney is carefully adapted to draw upon the surface of the flame just sufficient air to completely consume the quantity of gas which the burner is calculated to deliver4 ,,improvements ,,in ,,flat-,,flame ,,burners4 ,although1 there is no doubt1 they were made empirically1 and in ignorance of the real effects of pressure upon the flame1 the first steps towards increasing the efficiency of flat-flame burners were in the right direction of reducing the excessive pressure at which the gas was formerly allowed to burn4 ,they consisted in the adoption of simple arrangements for obstructing the passage of the gas through the burner1 and so retarding its flow4 ,the crudeness of the means which were employed is sufficient evidence that the end aimed at was1 at best1 but dimly discerned4 ,the body of the burner was stuffed with wool1 or pieces of wire gauze2 which impeded the progress of the gas2 reduced the quantity that would otherwise have been consumed2 and1 consequently1 diminished the velocity with which it issued from the burner4 ,unfortunately1 owing to the imperfect methods in use at that day for condensing and purifying the gas1 the burners so constructed became choked with the tarry matters held in suspension1 and carried forward by the gas2 and so1 after a comparatively short period of service1 were rendered entirely inoperative4 ,but1 altogether apart from the inconvenience and loss thus entailed 7which1 when improved modes of manufacture had removed the cause1 ceased to be experienced71 the arrangement was ill adapted for the purpose which it was designed to serve4 ,the rough and uneven nature of the material employed to stuff the burner caused the gas to eddy and swirl as it issued into the atmosphere1 and prevented it being supplied equally to all parts of the flame4 ,the consequence was that the advantages which ought to have been derived from the diminished pressure were neutralized by the unsteady flow acquired by the stream of gas2 and the illuminating power developed by the flame was little improvement upon what could previously be obtained by the manipulation of the tap controlling the supply of gas to the burner4 ,besides which1 from its unevenness1 the appearance of the flame was not so satisfactory4 ,it was not until the principles which regulate the production of light from coal gas came to be known and observed in the construction of burners1 that a modification of the old idea was arrived at1 which enabled the benefits of a reduced pressure to be obtained without any of the attendant evils hitherto experienced4 ,sidenote3 ,the first real improvement of the union-jet burner4 ,a modification in the construction of the union-jet which1 though slight1 was nevertheless a real improvement1 appears to have been made at an early period in the history of this burner4 ,instead of having the top of the burner perfectly flat1 it was made slightly concave2 more especially at its centre1 where the two jets of gas emerge4 ,the effect of this alteration was to enable the stream of gas to spread out better2 and thus to cause the flame to become broader at its base4 ,the shape of the flame was thereby improved2 and 7what is of more consequence7 its illuminating power increased1 because air was not drawn so readily into the midst of the flame4 ,the value of the arrangement is shown by the fact that it has been retained ever since1 and is made use of in the latest and most improved burners of this class4 ,prior to #ahfj1 numerous novel contrivances were introduced as improved burners2 but all were not equally valuable with the simple arrangement just described4 ,the construction of many of them1 indeed1 betrayed a lamentable ignorance of the first principles of gas combustion4 ,for instance1 one is described as a fishtail with four converging holes2 and there is an aperture in the centre of the burner for the admission of atmospheric air into the flame6 ,another was a batswing with two or more slits1 producing a series of flames amalgamated into one2 by which means it was supposed that an improved duty was obtained from the gas--unmindful1 or1 more probably1 in ignorance of the fact that the same quantity of gas1 properly consumed through one slit1 would yield a better light4 ,sidenote3 ,the double-flame burner4 ,a burner which1 at different times1 and under various names1 has been brought repeatedly into notice is the double-flame2 consisting of two batswing or union-jet burners set at an angle to each other1 so that their flames converge1 and merge into one4 ,when two gas flames are made to coalesce in this manner1 a greater amount of light is developed than the sum of that yielded by the separate flames2 provided that1 in the combined flame1 the gas is properly consumed1 without smoke4 ,the reason for this increase is twofold4 ,first1 the increased quantity of gas burnt in one flame enables a higher average temperature to be maintained2 and1 in addition1 a smaller surface of flame is exposed to the cooling action of the atmosphere than when the same quantity of gas is consumed in two flames4 ,second1 the pressure at which the gas burns is diminished1 because the initial velocity with which the streams of gas issue from the two burners is expended in impinging against each other1 and a thicker flame results2 the apparatus being1 as far as its effect is concerned1 a union-jet burner on a large scale4 ,the increase of light so obtained appears to have been noticed at an early period2 as a burner embodying the same principle is described and figured in ,clegg's ,treatise1 published in #ahdh4 ,in ,clegg's burner the gas issued from two perforated parallel plates inclined to each other2 but at a more recent period two fishtail burners were employed1 being mounted on separate tubes which branched out to a short distance from each other4 ,occasionally1 for experimental and show purposes1 it has been constructed with the two branches hinged together1 so as to show the different effects produced when the two burners are used separately and in combination4 ,at the present day it is made1 by various makers1 as one burner with two nipples1 as shown in the annexed illustration2 which doubtless is its most perfect form4 ,illustration3 ,,fig4 #e4--;,,duplex ,,burner4 ,the advantages of the double flame are not so obvious under the conditions which obtain at the present day as at the period when it was first introduced4 ,the increase of light it affords is most apparent when the gas is being consumed at an excessive pressure4 ,although1 in general1 it may be taken that any two flames1 when combined1 will develop a higher duty1 per cubic foot of gas consumed1 than separately2 yet it would appear that this is not so in every case4 ,when the gas is being consumed at the critical pressure which gives the best results1 the flames are so near the smoking point that the slight diminution of pressure experienced when the streams of gas impinge upon each other is sufficient to cause the combined flame to smoke4 ,moreover1 to such a stage of perfection have the ordinary flat-flame burners now been brought1 that1 for all ordinary consumptions1 it may be safely affirmed that equal1 if not superior results can be obtained with a single as with a double flame4 ,where1 however1 larger quantities of gas are required to be dealt with than can be effectively consumed in a single burner1 the principle of combining two or more burners together1 so that their flames shall mutually assist each other1 may be advantageously employed2 as is seen in the combination of flat-flame burners in the large lamps now employed in improved street lighting4 ,illustration3 ,,fig4 #f4--,,scholl',s ,,platinum ,,light ,,perfecter4 ,sidenote3 ,scholl's ,platinum ,light ,perfecter4 ,an ingenious device for improving the efficiency of union-jet burners was brought out some twenty years ago by a ,mr4 ,scholl1 of ,london1 and known as ,scholl's ,platinum ,light ,perfecter1 which is shown in the accompanying illustration4 ,it consisted of a little brass ring1 carrying a plate of platinum about #j4d inch long by #j4ae inch wide4 ,the ring fitted on to the top of the burner in such a manner that the platinum plate was held1 in a vertical position1 between the two orifices from which the gas emerged4 ,the jets of gas1 instead of impinging upon each other1 impinged against the plate1 and united above to form the flame4 ,by the interposition of the metal plate1 the velocity of the gas was much reduced2 and a thicker and more sluggish flame was produced1 with the result of increasing its illuminating power4 ,when the apparatus was used upon a burner having very small orifices1 and delivering its gas at a high pressure1 the increase of light obtained was very striking2 but with lower pressures the advantage derived from its use was correspondingly diminished4 ,this is very clearly shown by the following table1 which is extracted from a report1 by ,captain ,webber and ,mr4 ,rowden1 on experiments upon gas-burners1 carried out at the ,paris ,universal ,exhibition1 #ahfg4d #d ,see ,journal of ,gas ,lighting1 ,vol4 ,,xviii41 p4 #hh4 ---------------------------------------- ------------------------------ ,kind of ,burner4 ,cubic ,pressure ,illuminating ,power4 ,feet of in --------------------,increase ,gas ,inches4 ,without ,with per per ,perfecter4,perfecter4 ,cent4 ,hour4 ---------------------------------------- ----------------------------- ,leoni's fishtail1 ,no4 #b 4 #c #j4hd #a4c #d4a #bae ,leoni's fishtail1 ,no4 #c 4 #c #j4df #b4d #d4f #ia #d #j4gj #b4h #f4e #acb #c #j4ca #c4d #e4j #dg ,leoni's fishtail1 ,no4 #d 4 #d #j4dg #d4e #g4f #fh #e #j4ga #e4j #i4b #hd #d #j4db #e4c #f4i #cj ,leoni's fishtail1 ,no4 #e 4 #e #j4fj #f4a #h4c #cf #f #j4ha #g4a #aj4j #dje ,leoni's fishtail1 ,no4 #f 4 #d #j4ca #f4b #h4j #bif #e #j4df #h4j #aj4d #cjg ---------------------------------------- ----------------------------- #e ,flame flickers4 #f ,do4 #g ,flame flickers a great deal4 ,burners were also made with the metal plate forming part of the burner head2 and1 instead of being of platinum1 it was sometimes formed of thin steel1 or other commoner metal4 ,where platinum was used1 some advantage probably accrued from its becoming incandescent2 but1 of course1 any benefit arising from this source was not obtained when steel was employed4 ,the remarks which have been made respecting the limited applicability of the double-flame burner will apply1 with equal force1 to the apparatus under notice4 ,although it effected an undoubted improvement when applied to burners ill adapted to the pressure at which the gas was supplied1 equally good results could be obtained without its aid1 when a burner was employed suited to the quality and pressure of the gas supplied4 ,sidenote3 ,leoni's flat-flame burners4 ,perhaps the most efficient flat-flame burners available prior to #ahfg were those made by ,mr4 ,s4 ,leoni1 of ,london4 ,one of these is shown in fig4 #g4 ,this maker produced both batswing and union-jets2 various sizes being made of each burner4 ,besides affording fairly good results from the gas consumed1 the burners were supplied at a very moderate price4 ,their distinguishing feature was the peculiar substance of which the burner-tips were formed4 ,this was a material invented by ,mr4 ,leoni1 and named by him adamas4 7,the precise composition of adamas is a trade secret2 but it appears to consist of a mixture of various minerals or earths1 moulded in a clayey or plastic condition1 and then burnt47 ,previous to his invention1 the tip of the burner1 or the burner head1 had been made1 almost exclusively1 of iron or brass4 ,there were1 however1 some grave defects inherent in the use of metal for this purpose4 ,the orifices of union-jets and the slits of batswings in course of time became much obstructed by the corrosion of the metal2 and the efforts made to remove the obstruction only served to destroy the burner more quickly1 by increasing the size and injuring the precise shape of the apertures4 ,the adamas tips1 on the other hand1 perfectly withstood the high temperature to which they were exposed1 were quite incorrodible1 and were sufficiently hard to endure a considerable degree of even rough usage4 ,by constructing the tip of this material1 the efficiency of the burner was improved in many ways4 ,the liability of the burner to corrosion being removed1 and the inconvenience due to this cause done away with1 the life of the burner was prolonged1 and the expense of renewal consequently reduced4 ,but1 in addition to these advantages1 there was yet another direction in which the adamas tip contributed to enhance the utility of the burner4 ,this was in maintaining a higher temperature of the flame2 and arose from its inferior capacity1 compared with metal1 for conducting heat from the flame4 ,that the advantage derived from this source1 although unimportant1 was not altogether imaginary1 will be apparent when it is mentioned that metal burners1 when in operation1 usually attain to a temperature of from #djj deg4 to #ejj deg4 ,fahr4--an indication of the amount of heat being continuously abstracted from the flame4 ,the adoption of a non-conducting material for the burner-tip1 while it did not entirely prevent1 considerably reduced the loss of heat4 ,illustration3 ,,fig4 #g4--,,leoni',s ,,flat-,,flame ,,burner4 ,two varieties of each class of burner were made by ,mr4 ,leoni4 ,in the one burner1 the adamas tip was inserted into an iron stem2 in the other1 the tip was inserted in a brass body1 which fitted on to the iron stem4 ,between the brass body and the iron stem of the latter burner there was affixed a layer of wool1 designed to check the pressure at which the gas was supplied4 ,owing1 very probably1 to the unsuitability of the material 7wool7 used for this purpose1 the result was not satisfactory2 as1 according to the statements of ,messrs4 ,webber and ,rowden1 in the report previously cited1 no difference could be detected1 in many experiments1 between the results yielded by the burner with or without the layer of wool4 ,some light is shed upon this apparent anomaly by certain experiments made by the writer to determine the pressure at which gas issues from various burners4 ,with one of ,leoni's ,no4 #d union-jets1 under an initial pressure of #a inch 7the pressure at the inlet when the burner is in operation71 the pressure at the outlet of the burner1 when the layer of wool was employed1 was #j4aa inch2 but from the same burner1 when the layer of wool was removed1 the gas issued at a pressure of only #j4jg inch4 ,thus the effect of inserting the layer of wool in the burner was exactly the opposite of that which it was intended to produce2 the pressure of the issuing gas stream being increased instead of diminished4 ,b,r,oe,n,n,e,r',s ,,burners4 ,the credit of having produced the first flat-flame burners designed upon scientifically correct principles belongs undoubtedly to ,herr ,julius ,broenner1 of ,frankfort-on-the-,maine4 ,long before the date of his invention1 efforts had been made to reduce the pressure of the gas within the burner4 ,but these endeavours were carried out in so hap-hazard a fashion as to lead to the belief that no definite conception was entertained as to what was really required4 ,as we have seen1 layers of wool had been employed2 but the area of the interstices1 or the gas-way through the material1 was a matter of the merest accident4 ,and there was not the slightest guarantee that the same conditions should prevail in any two burners4 ,herr ,broenner shrewdly detected the cause of former failures1 as he clearly perceived the end which it was requisite to attain1 and towards which previous inventors had been but blindly groping4 ,having formed a right estimate of the requirements to be fulfilled1 and the difficulties to be surmounted1 he set about accomplishing the desired result by other means4 ,there were two causes which had chiefly contributed to the unsuccessful issues of previous attempts4 ,one was the uncertain and indefinite operation of the means employed for diminishing the pressure2 the other was the inadequate provision for enabling the gas to lose the current1 or swirl1 acquired in passing the diminishing arrangement1 and come to a state of comparative rest before issuing into the atmosphere4 ,both these errors were successfully avoided in ,broenner's invention--the former by making the inlet to the burner of restricted and definite dimensions1 and of less area than the outlet1 or slit2 the latter by enlarging the chamber1 or place of expansion within the burner1 as well as by the different arrangement adopted for diminishing the pressure4 ,illustration3 ,a ,,top4 ,b ,,top4 ,,fig4 #h4--;,b,r,oe,n,n,e,r',s ,,burners4 ,sidenote3 ,construction of ,broenner's burners4 ,the general appearance of ,broenner's burner is pear-shaped2 and in size it is considerably larger than an ordinary burner designed to pass an equal quantity of gas4 ,it consists of a cylindrical brass body surmounted by a steatite top1 and tapering to a very small diameter at its lower end1 or inlet2 the latter being closed by a plug of steatite1 in which is a rectangular slot1 or aperture1 of accurately defined dimensions4 ,the size of this aperture determines the quantity of gas which1 at any particular pressure1 is admitted to the burner2 and the slit1 or outlet of the burner1 being of greater area than the inlet1 ensures the gas being delivered from the burner at a lower pressure than that at which it enters it4 ,by varying the respective dimensions of these two openings1 and their relation to each other1 the burner may be regulated to deliver its gas at any required pressure short of the initial pressure at the entrance to the burner4 ,the enlargement of the cylindrical body provides an expansion chamber1 wherein the velocity of the stream of gas which rushes through the narrow opening at the inlet of the burner is checked1 and any agitation or unsteadiness which may have been imparted to it is subdued before the gas issues into the atmosphere and is consumed4 ,there are two kinds of tops for the burners1 which are distinguished by the letters ,a and ,b4 ,the ,b top is of the ordinary semi-spherical type1 giving a true batswing-shaped flame2 the ,a top is flatter1 almost square in form1 and yields a flame taller than1 but not so broad as the former4 ,in consequence of this difference in the shape of its flame1 the latter burner is better adapted for use in globes4 ,the general appearance of the burners1 and their distinguishing peculiarities1 will be clearly understood from the illustrations4 ,sidenote3 ,properties of steatite4 ,the material of which the more important parts of the burner are constructed is eminently adapted for the purpose4 ,steatite is a mineral which1 as found in nature1 is so soft as to be readily turned in a lathe1 and shaped to any design2 but when heated up to about #bjjj deg4 ,fahr4 it becomes almost as hard and durable as flint1 while perfectly retaining its form and colour4 ,these properties peculiarly qualify it for receiving a slit or orifice1 which1 though of minute proportions1 must be accurately formed to precise dimensions4 ,besides which1 like adamas1 its capacity for conducting heat away from the flame is so limited that1 in this respect1 it has a considerable advantage over metal for the purpose of being formed into gas-burners4 ,sidenote3 ,varied adaptability of the ,broenner burner4 ,the following tables1 which are extracted from the report of the ,committee of the ,british ,association appointed to investigate the means for the development of light from coal gas of different qualities1#h exhibit the very satisfactory results obtained by the use of these burners4 ,in ,table ,i41 the gas operated upon was cannel gas 7such as is generally supplied in ,scotland71 and possessed an illuminating power1 when employed in the standard burner1 of #bf candles per #e cubic feet4 ,table ,,ii4 contains the results of determinations with common gas 7such as is used in ,london1 and generally throughout the greater part of ,england72 #e cubic feet of which1 in the standard burner1 gave an illuminating power of #af candles4 ,the first and second columns of the tables refer to the different sizes of the tops and bottoms of the particular burners employed2 there being in all some #af sizes of the one1 and #aa sizes of the other4 ,these1 being interchangeable1 permit of a great variety of combinations2 and enable a burner to be selected suited to any particular quality or pressure of gas4 ,for as with pressure1 so with illuminating power3 ,in order to obtain the utmost lighting efficiency1 different burners are required for gases differing in quality or their degree of richness4 ,a burner which1 with gas of one quality1 will yield excellent results1 may1 under the same conditions of pressure and supply1 be totally unsuited to gas of another quality4 ,that this should be so will be evident from a consideration of what has been said as to the theory of burning gas to the best advantage2 and1 in brief1 results from the richer gas containing in its composition a greater proportion of carbon1 and so requiring an increased supply of air for its thorough combustion4 ,this increased supply of air can only be obtained 7with flat-flame burners7 by causing the gas to issue into the atmosphere at a higher pressure2 and so it comes about that1 compared with the quantity of gas to be delivered through them1 the slits of batswing and the orifices of union-jet burners must be considerably narrower when intended for cannel gas than when common gas is to be consumed4 ,in other words1 in order to develop its full illuminating power1 it is essential that the pressure at which the gas issues from the burner should be proportioned to its quality4 ,the gist of the matter is set forth in the general statement that the poorer the quality of the gas1 the lower must be the pressure at which it is consumed2 and vice versa4 #h ,see ,journal of ,gas ,lighting1 ,vol4 ,,xxxii41 p4 #dbc1 and ,vol4 ,,xxxvi41 p4 #cgf4 ,,table ,i4 ---------------------------------------- ------------------------------ ,,at #j4e-;,,inch ,,at #a4j-;,,inch ,,at #a4e-;,,inch ,,pressure4 ,,pressure4 ,,pressure4 ---------------------------------------- ---------------------- ,no4 ,no4 ,cubic,illumi-,illumi- ,no4 ,no4 ,cubic,illumi-,illumi- of of ,feet nating nating of of ,feet nating nating ,burner4,top4per ,power4 ,power ,burner4,top4per ,power4 ,power ,hour4 per ,five ,hour4 per ,five ,cub4 ,ft4 ,cub4 ,ft4 ---------------------------------------- ---------------------- #b #b #a4bj #e4jg #bd4ac #b #b #a4dj #e4be #ah4ge #b #c #a4dj #f4fd #bc4ga #b #c #a4ie #g4cg #ah4ij #b #d -- ,smokes -- #b #d #b4cj #aj4cc #bb4df #b #e -- -- #b #e #b4dj #aa4bd #bc4db #b #f -- -- #b #f -- ,smokes -- ---------------------------------------- ---------------------- #b-a_/b #b #a4dj #e4ec #ai4ge #b-a_/b #b #a4ij #h4cj #ba4hd #b-a_/b #c #a4gj #h4dh #bd4id #b-a_/b #c #b4cj #aj4ad #bb4jd #b-a_/b #d #b4jc #aj4cc #be4di #b-a_/b #d #b4gj #ab4jh #bb4cg #b-a_/b #e -- ,smokes -- #b-a_/b #e #b4he #ad4bi #be4jg #b-a_/b #f -- -- #b-a_/b #f #c4jj #ae4ba #be4ce ---------------------------------------- ---------------------- #c #b #a4de #f4bg #ba4fb #c #b #b4jj #h4dh #ba4bj #c #c #a4ij #h4ff #bb4gi #c #c #b4dj #aa4cd #bc4fc #c #d #b4ac #aa4bd #bf4ci #c #d #b4hj #ad4hd #bf4ej #c #e -- ,smokes -- #c #e #c4ae #ag4jd #bg4bj #c #f -- -- #c #f #c4be #ah4jg #bg4hj ---------------------------------------- ---------------------- #c-a_/b #b #a4ej #e4ha #ai4cf #c-a_/b #b #b4ab #h4he #bj4hg #c-a_/b #c #a4ie #h4cj #ba4bh #c-a_/b #c #b4ee #ab4fc #bd4gf #c-a_/b #d #b4ee #ab4jh #bc4fh #c-a_/b #d #c4jj #ad4dg #bf4ab #c-a_/b #e #b4hj #ad4ch #be4fh #c-a_/b #e #c4ej #ah4jg #be4ha #c-a_/b #f #c4jj #ae4eh #be4ig #c-a_/b #f #c4fj #ai4de #bg4ja ---------------------------------------- ---------------------- #d #b #a4fj #f4cf #ai4hg #d #b #b4cj #i4gg #ba4bd #d #c #b4aj #aj4fi #be4de #d #c #b4ij #ac4hc #bc4hd #d #d #b4fe #ac4cg #be4bc #d #d #c4cj #ag4jf #be4he #d #e #c4de #ag4fa #be4eb #d #e #d4aj #ba4eg #bf4cj #d #f #c4ee #ah4jg #be4de #d #f #d4bj #bb4dj #bf4ff ---------------------------------------- ---------------------- #e #b #a4gg #g4ch #bj4he #e #b #b4fj #i4fh #ah4ha #e #c #b4cj #aa4ij #be4hg #e #c #c4cj #ac4fd #bj4fg #e #d #c4cj #ae4dj #bc4cc #e #d #d4jj #ai4ia #bd4ad #e #e #d4aj #bj4gd #be4bi #e #e #e4jj #be4cf #be4cf #e #f #d4cj #bb4fh #bf4cg #e #f #e4cj #bg4ff #bf4aj ---------------------------------------- ---------------------- ,,table ,,ii4 ---------------------------------------- ----------------------------- ,,at #j4e-;,,inch ,,at #a4j-;,,inch ,,at #a4e-;,,inch ,,pressure4 ,,pressure4 ,,pressure4 ---------------------------------------- --------------- ,no4 ,no4 ,cubic,illumi-,illum4,cubic,illumi-,illu m4 ,cubic,illumi-,illum4 of of ,feet nating ,power ,feet nating ,power ,feet nating ,power ,top4,bot-per ,power4 per per ,power4 per per ,power4 per tom4,hour4 ,five ,hour4 ,five ,hour4 ,five ,cub4 ,cub4 ,cub4 ,ft4 ,ft4 ,ft4 ---------------------------------------- ----------------------- ,a#b #a -- -- -- #a4e #b4g #i4j #b4j #d4j #aj4j #b #a4f #b4i #i4a #b4d #e4b #aj4h #c4a #f4h #aa4j #ba_/b #b4j #c4i #i4h #b4i #f4h #aa4g #c4h #i4d #ab4d ,a#c #c #b4a #d4d #aj4e #c4b #g4h #ab4b #d4d #aj4f #ab4j #ca_/b #b4e #d4h #i4f #c4h #i4b #ab4a #d4i #ab4b #ab4d #d #b4e #e4d #aj4h #c4h #i4f #ab4g #e4b #ac4f #ac4a #da_/b #c4j #f4d #aj4g #d4e #aj4h #ab4j #e4i #ad4h #ab4e #e #c4b #g4g #b4j #e4a #ac4b #ac4j #f4h #ah4j #ac4b #f #c4g #h4g #aa4h #e4h #ae4e #ac4c #g4g #ba4j #ac4f #g #c4e #h4f #ab4c #e4i #af4j #ac4f #h4d #bc4j #ac4g #h #c4g #i4j #ab4b #f4b #af4h #ac4e #h4f #bc4d #ac4f ,b#a #a -- -- -- #a4c #b4c #h4h #a4h #c4e #i4g ,b#b #b #a4c #b4c #h4h #b4a #d4d #aj4e #b4h #f4d #aa4d #ba_/b #a4f #c4j #i4d #b4e #f4j #ab4j #c4d #h4d #ab4d ,b#c #c #b4j #c4h #i4j #c4j #g4b #ab4j #d4a #aj4a #ab4c #ca_/b #b4c #d4c #i4c #c4d #g4g #aa4c #d4e #aa4j #ab4b ,b#d #d #b4c #d4g #j4b #c4f #h4h #ab4b #e4j #ac4j #ac4j #da_/b #b4g #e4i #aj4i #d4c #aj4d #ab4a #e4f #ae4j #ac4d ,b#e #e #c4a #g4j #aa4c #d4i #ab4i #ac4b #f4e #ah4j #ac4h ,b#f #f #c4h #i4f #ab4f #e4i #af4d #ac4h #h4j #bc4j #ad4d ,b#g #g #d4j #aj4b #ab4h #f4f #ai4j #ad4d #i4j #bf4j #ad4d ,b#h #h #d4g #aa4h #ab4f #g4c #bb4j #ae4a #i4f #cj4j #ae4g ---------------------------------------- ----------------------- ,sidenote3 ,pressure of gas with the ,broenner burner4 ,doubtless the chief cause of the remarkable efficiency of the ,broenner over previous burners is to be found in the pressure at which the gas flows from the burner and is consumed4 ,in the course of some experiments made to determine the pressure at which gas is delivered from various burners1 the writer found that from a ,no4 #d ,broenner1 with an initial pressure--i4e41 the pressure at the inlet when the burner is in operation--of #a inch1 the gas issued at a pressure of only #j4je inch2 and with an initial pressure of #j4e inch1 the outlet pressure was only #j4jc inch4 ,on the other hand1 a ,no4 #d steatite flat-flame burner1 without any arrangement for retarding the flow of the gas1 under the same initial pressure gave at the outlet #j4af inch and #j4je inch respectively4 ,the absence of anything within the burner to cause the gas to swirl1 or to issue with an unsteady flow1 must also be credited with contributing1 in no slight degree1 to the favourable results yielded by these burners4 ,,the ,,hollow-,,top ,,burner4 ,in the hollow-top burner we have one of the most notable improvements which have been effected in flat-flame burners4 ,a simple modification of the batswing--the earliest of flat-flame burners--it is not more complicated in its details than is that burner4 ,yet1 simple as it is1 its construction exhibits an important advance upon the original batswing4 ,indeed1 this burner may be said to embody the only considerable improvement that has been made in the distinctive features of the batswing since the introduction of the latter burner1 which1 as we have seen1 took place as early as the year #ahaf4 ,sidenote3 ,the hollow-top an improved batswing burner4 ,in its outward form1 the hollow-top burner differs little1 if at all1 from the batswing2 but a slight modification which has been adopted in the arrangement of its interior has produced a very marked result in improving the shape of the flame yielded by the burner1 and1 to some extent1 in the results1 as regards illuminating power1 which it is capable of affording4 ,in this burner1 as its name implies1 the interior of the top or head of the burner is hollowed out1 forming an enlargement of the cavity or chamber within the burner1 and 7what is chiefly important7 making the shell of the dome-shaped burner head of equal thickness throughout4 ,in the ordinary batswing1 in consequence of the varying thickness of the burner at this part1 the slit is much deeper in the middle than at any other part of its length1 and gradually decreases in depth towards each end4 ,as the resistance to the passage of the gas1 or the friction which it encounters1 increases with the depth of the slit1 the gas passes out from the burner at the ends of the slit more readily than in the middle2 producing a wide-stretching flame1 of scanty height in proportion to its width4 ,from the same cause the flame is not of equal thickness throughout2 being thinner in the middle than at the ends4 ,moreover1 the outer extremities of the flame1 extending so far beyond the body of the burner1 are unable to retain the form given to them by the lateral flow of the gas at the ends of the slit2 the resistance1 presented by the atmosphere1 together with the natural tendency of the gas to ascend1 causing the under portion of the flame to fold back upon itself4 ,as one result of this combination of untoward circumstances1 the flame is liable to smoke with a slight agitation of the surrounding air4 ,in the hollow-top burner1 the slit is of equal depth throughout its length2 and the resistance offered to the passage of the gas being the same in all parts of the slit1 the gas flows through the middle as readily as at the ends--nay1 in reality rather more so1 owing to the innate ascensive power of the gas1 due to its being lighter than air4 ,the peculiar hollowing-out of the head of the burner1 also1 withdraws the ends of the slit out of the direct course or current of the gas through the burner2 so that the tendency of the stream of gas to issue at these points1 in preference to going through the middle of the slit1 is further checked4 ,the consequence is that the shape of the flame is considerably improved2 it being taller1 more compact1 and not so broad as that of the batswing4 ,in addition1 the flame being of equal thickness throughout1 its illuminating power is somewhat improved2 while1 from its compactness1 it is better enabled to resist atmospheric influences4 ,with this alteration in the shape of the flame all original resemblance to a batswing is entirely destroyed2 but the appearance of the flame of the new burner is much more agreeable to the eye than that of the older batswing4 ,illustration3 ,,fig4 #i4--,,original ,,hollow-,,top ,,burner4 7,from ,wadsworth's ,specification47 ,sidenote3 ,who invented the hollow-top burner4 ,as has been exemplified in so many instances in the history of invention1 the hollow-top burner was not appreciated at its true value until long after it had been brought into existence4 ,it appears to have been originally invented by ,joseph and ,james ,wadsworth1 of ,marple and ,salford1 and was patented by them in #ahfj4 ,according to the specification of the inventors1 the burners might be made either in solid or sheet metal1 as will be seen from the accompanying illustrations1 copied from the drawings in the specification4 ,but there were difficulties in the way of casting the burners in solid metal which do not seem to have been surmounted2 and those produced under the patent appear to have been made exclusively of sheet brass4 ,for many years these burners were made and sold without their peculiarities attracting any marked attention2 which would seem to imply that their faulty construction precluded the attainment of all the advantages afforded by the burner as we know it4 ,sidenote3 ,sugg's hollow-top burner4 ,the superior results which the hollow-top burner was calculated to afford did not become fully apparent until the burner was made of non-conducting material1 and greater care exercised in its construction4 ,this appears to have been done in ,germany earlier than in this country4 ,but1 in ,england1 it was undoubtedly ,mr4 ,sugg who first turned his attention to the improvement of the burner1 and demonstrated its merits4 ,mr4 ,sugg commenced the manufacture of this burner in steatite in the year #ahfh2 and since that time the burner has been extensively employed1 and its advantages widely recognized4 ,the superiority of hollow-top burners produced by ,mr4 ,sugg to those previously manufactured1 is chiefly the result of their being made in steatite instead of in metal4 ,with this material1 greater exactness and uniformity are obtained in the shape and dimensions of the burner than when metal is employed2 besides which there is 7what has been before referred to7 the advantage arising from its inferior conductive capacity for heat1 and its non-liability to corrosion4 ,another improvement1 also due to ,mr4 ,sugg1 and which is productive of noticeable results1 consists in cutting the slit of the burner with a circular saw1 applied from above1 so as to make the ends of the slit curved instead of horizontal2 by which means the tendency of the gas to issue laterally at the ends of the slit1 and form horns to the flame1 is lessened4 ,mr4 ,sugg's table-top burner 7which was introduced in #ahhj71 in addition to the characteristic features of the hollow-top1 has a rim-like projection from the burner1 below the slit2 its object being to protect the flame from the disturbing influence of the uprush of air in its immediate vicinity1 and so preserve its shape unaltered1 while diminishing its liability to smoke4 ,prior to ,mr4 ,sugg--namely1 in the early part of #ahgi--,mr4 ,bray had successfully obviated this injurious action upon the flame of the ascending current of air1 by affixing to the burner two arms of brass1 so placed as to be immediately under the projecting wings of the flame4 ,illustration3 #ahfh ,,burner4 #ahgd ,,burner4 ,,table-,,top ,,burner4 ,,fig4 #aj4--,,sugg',s ,,hollow-,,top ,,burners4 ,,bray',s ,,burners4 ,the burners of ,messrs4 ,george ,bray and ,co4 have deservedly acquired a world-wide reputation1 and are in extensive use wherever gas lighting is known4 ,their distinguishing characteristic1 and that which has won for them the high repute in which they are held1 is the union of cheapness with remarkable efficiency4 ,in all the various descriptions and classes of burners which are produced by this firm1 the characteristic referred to is preserved2 although it is needless to add that the different varieties are not equally efficient4 ,of the three forms of flat-flame burners we have been considering--batswing1 union-jet1 and hollow-top--the one which1 more than any other1 has been the speciality of the firm is the union-jet2 and it is with the development of this class of burner that the name of ,bray is most intimately and honourably associated4 ,illustration3 ,,union-,,jet4 ,,hollow-,,top ,,or ,,slit-,,union4#i ,,batswing4 ,,fig4 #aa4--;,,bray',s ,,regulator ,,burners4 #i ,the name slit-union1 by which ,mr4 ,bray prefers to designate this burner1 he states to be derived from the resemblance of its flame to that of the union-jet burner2 while it is produced by means of a slit4 ,sidenote3 ,bray's regulator burner4 ,sidenote3 ,bray's special burner4 ,the regulator union-jet1 which was the first notable burner produced by ,messrs4 ,bray1 has received1 perhaps1 a wider application than any other single gas-burner4 ,it consists of a cylindrical brass case1 screwed at one end for insertion into the fittings1 and at the other containing a tip of enamel--a material invented by ,mr4 ,bray1 and apparently of somewhat similar composition to the adamas of ,mr4 ,leoni--the enamel tip being perforated1 in the usual manner1 with two holes1 set at an angle to each other1 for the outflow of the gas4 ,the distinctive feature of this burner is the introduction into the lower part of the brass case of a layer1 or layers1 of muslin2 designed to check in some degree1 and to steady the current or flow of the gas through the burner4 ,at the time of its introduction1 this burner compared very favourably1 as regards the results it yielded1 with other burners in common use2 and its fairly good performances1 together with the very low price at which it can be sold1 cause it still to be extensively employed wherever the attainment1 from the gas consumed1 of the highest obtainable results may be subordinated to cheapness1 or in situations where1 from delicacy of construction or from the care and attention demanded1 a more efficient burner may not be so suitable4 ,but in the matter of developing the illuminating power of the gas employed1 the regulator is far surpassed by the more recently introduced special burner of the same makers4 ,illustration3 ,,union-,,jet4 ,,hollow-,,top ,,or ,,slit-,,union4 ,,batswing4 ,,fig4 #ab4--;,,bray',s ,,special ,,burners4 ,mr4 ,bray's series of special burners--embracing union-jet1 hollow-top1 and batswing--are constructed upon the principle of1 and in form are somewhat similar to ,broenner's burners1 which have already been fully described4 ,apart from its being of greater bulk1 the main divergence in the construction of the special burner from that of the earlier regulator is the introduction1 into the lower part of the brass case1 of a plug or washer of enamel1 pierced by a small circular hole for the admission of gas into the burner2 the diameter of this hole determining the quantity of gas which1 at any particular pressure1 is admitted into the burner4 ,just above the enamel washer1 a layer of muslin is inserted1 as in the regulator burner2 which1 in this case1 is for the purpose of subduing the agitation1 or swirl1 acquired by the current of gas in passing through the narrow aperture in the washer4 ,a tip of enamel1 made of the particular description 7union-jet1 hollow-top1 or batswing7 required1 fitting into the upper part of the brass case1 completes the burner4 ,the objects aimed at in the special burner are to cause the gas to be consumed at the lowest pressure compatible with the maintenance of a firm flame1 and with the least agitation1 or swirl1 in the current of gas as it issues from the burner4 ,the former is attained1 as in ,broenner's burners1 by diminishing the area of the opening admitting into the burner1 without a corresponding diminution of the orifices through which the gas issues into the atmosphere2 the latter1 by the interposition of the layer of muslin which is immediately above the diminishing arrangement1 as well as by the enlargement of the gas chamber in the upper part of the burner4 ,the improvement thus effected in the illuminating power developed from the gas is well shown in the following tables extracted from an exhaustive series of tests of gas-burners carried out by ,mr4 ,t4 ,fairley1 ,f4,r4,s4,e41 ,borough ,analyst of ,leeds1 and embodied by him in a report presented to the ,leeds ,corporation4 ,the full text of the report will be found in the ,journal of ,gas ,lighting for ,february #f1 #ahhc4 ,medium ,lighting ,power ,union-,jets4 ---------------------------------------- ------------------------------ ,regulator ,burners4 ,special ,burners4 ---------------------------------------- ---------------------- ,no4 ,pres- ,cubic,illumi-,illumi-,no4 ,pres- ,cubic,illumi-,illumi- of sure ,feet nating nating of sure ,feet nating nating ,burnerin per ,power ,power ,burnerin per ,power ,power ,inches,hour in per #e ,inches,hour in per #e ,stand4 ,cubic ,stand4 ,cubic ,candls4,feet4 ,candls4,feet4 ---------------------------------------- ---------------------- #c #j4e #c4ej #f4h #i4g #c #j4e #c4dc #aa4c #af4d #c #a4j #d4hj #f4i #g4b #c #a4j #d4ij #ae4f #ae4h #c #a4e #f4bj #g4e #f4je #c #a4e #f4jc #ag4f #ad4f #d #j4e #d4fe #ab4b #ac4a #d #j4e #c4gc #ac4c #ag4h #d #a4j #f4fg #ad4b #aj4f #d #a4j #e4ae #ag4d #af4i #d #a4e #h4af #ad4b #h4h #d #a4e #f4eg #bb4d #ag4a #e #j4e #e4gb #ag4j #ad4i #e #j4e #d4hj #ag4f #ah4c #e #a4j #g4ig #bj4j #ab4f #e #a4j #f4fg #bd4d #ah4c #e #a4e #i4gc #ba4h #aa4b #e #a4e #h4cj #cj4j #ah4b #f #j4e #e4ij #ah4j #ae4b #f #j4e #e4dh #bj4a #ah4c #f #a4j #h4ce #bc4j #ac4h #f #a4j #g4fe #bh4d #ah4f #f #a4e #aj4fj #bh4j #ac4b #f #a4e #i4bj #cd4b #ah4g ---------------------------------------- ---------------------- ,medium ,lighting ,power ,slit-,unions4 ---------------------------------------- ------------------------------ ,regulator ,burners4 ,special ,burners4 ---------------------------------------- ---------------------- ,no4 ,pres- ,cubic,illumi-,illumi-,no4 ,pres- ,cubic,illumi-,illumi- of sure ,feet nating nating of sure ,feet nating nating ,burnerin per ,power ,power ,burnerin per ,power ,power ,inches,hour in per #e ,inches,hour in per #e ,stand4 ,cubic ,stand4 ,cubic ,candls4,feet4 ,candls4,feet4 ---------------------------------------- ---------------------- #c #j4e #d4bb #ac4h #af4d #c #j4e #c4jd #aj4h #ag4h #c #a4j #f4cg #bj4b #ae4i #c #a4j #d4fa #af4d #ag4f #c #a4e #h4ad #be4h #ae4i #c #a4e #e4hh #ai4i #af4i #d #j4e #d4be #ad4h #ag4d #d #j4e #c4hb #ad4b #ah4f #d #a4j #e4hh #bj4f #ag4e #d #a4j #e4fi #bj4h #ah4c #d #a4e #g4ie #bf4e #af4f #d #a4e #g4ce #be4f #ag4e #e #j4e #e4be #ai4j #ah4b #e #j4e #d4ab #ae4d #ah4g #e #a4j #h4ad #bh4d #ag4de #e #a4j #f4cg #bc4d #ah4d #e #a4e #aj4bj #cf4d #ag4h #e #a4e #g4id #bh4e #ah4j #f #j4e #e4fg #bb4b #ai4f #f #j4e #e4jj #ai4f #ai4f #f #a4j #h4fj #cc4f #ai4d #f #a4j #g4ee #bi4j #ai4b #f #a4e #aa4aj #ci4e #ag4h #f #a4e #i4gj #cg4j #ai4a ---------------------------------------- ---------------------- ,medium ,lighting ,power ,batswings4 ---------------------------------------- ------------------------------ ,regulator ,burners4 ,special ,burners4 ---------------------------------------- ---------------------- ,no4 ,pres- ,cubic,illumi-,illumi-,no4 ,pres- ,cubic,illumi-,illumi- of sure ,feet nating nating of sure ,feet nating nating ,burnerin per ,power ,power ,burnerin per ,power ,power ,inches,hour in per #e ,inches,hour in per #e ,stand4 ,cubic ,stand4 ,cubic ,candls4,feet4 ,candls4,feet4 ---------------------------------------- ---------------------- #c #j4e #d4af #ab4f #ae4a #c #j4e #c4cg #ab4d #ah4d #c #a4j #e4fd #af4f #ad4h #c #a4j #e4be #bj4d #ai4d #c #a4e #g4hc #ba4j #ac4d #c #a4e #g4ac #bd4j #af4h #d #j4e #d4bf #ad4j #af4d #d #j4e #c4fg #ac4j #ag4g #d #a4j #f4gd #ba4b #ae4f #d #a4j #e4ee #bj4f #ah4f #d #a4e #g4ha #bd4j #ae4c #d #a4e #g4ac #bf4j #ah4b #e #j4e #d4gf #ae4d #af4b #e #j4e #c4hf #ad4f #ah4i #e #a4j #f4ic #bj4d #ad4g #e #a4j #e4he #bb4f #ai4d #e #a4e #h4gb #be4h #ad4g #e #a4e #g4ec #bh4j #ah4f #f #j4e #f4jd #bj4j #af4e #f #j4e #d4hf #ai4d #bj4j #f #a4j #h4hb #bi4d #af4f #f #a4j #g4ec #ca4f #ba4j #f #a4e #aa4aj #ca4f #ad4b #f #a4e #i4fj #ci4j #bj4d ---------------------------------------- ---------------------- ,the quality of the gas operated upon averaged about #ai candles when tested with the ,standard ,london ,argand ,burner4 ,in a former part of this treatise it was remarked that the flames produced by the modern representatives#aj of the batswing and fishtail burners have lost the original resemblance to the objects whence the names of those burners were derived2 and that the two flames have gradually approached each other in shape1 until1 in their latest developments1 they are practically identical4 ,we have seen how that1 by the invention of the hollow-top1 a burner is obtained apparently1 to all outward appearance1 the same as the batswing1 yet giving a greatly improved form of flame4 ,we have now to learn how the fishtail1 or union-jet burner has been modified so as to yield a flame closely agreeing with that produced by the improved slit burner4 #aj ,although the true batswing is still in common use1 ,i look upon the hollow-top as being its modern representative2 seeing that1 in a great many instances1 it has superseded the former burner--of which1 indeed1 it is only an improved form4 ,sidenote3 ,how the union-jet burner has been improved4 ,as first constructed1 the union-jet burner gave a tall1 narrow flame2 its extremity being forked and jagged like the tail of a fish4 ,besides being unsightly1 this form of flame was ill-adapted to develop1 to anything like its full extent1 the illuminating power of the gas4 ,in order to obtain the best results1 as regards illuminating power1 the heat-intensity of the flame must be very high1 so as to bring up the temperature of the particles of carbon liberated in the flame to the necessary degree of incandescence4 ,to this end there must be concentration of the flame1 in order to utilize to the full the heat of combustion4 ,with the tall flame produced by the original union-jet burner there was too much exposure to the atmosphere for the flame to attain to the requisite intensity of heat2 as well as considerable liability of the gas being brought too early into intimate contact with air1 and so oxidized1 or fully consumed1 before its carbon had been raised to the temperature necessary to enable it to give out light4 ,with the burner in its improved form the height of the flame is much curtailed1 while it is broadened1 and made more even and compact4 ,this alteration has been chiefly brought about by two modifications in the construction of the burner-tip--first1 by hollowing out its flat upper surface2 and1 second1 by altering the angle at which the two streams of gas emerge from the burner4 ,by scooping out the central portion of the flat top of the burner1 so as to form a hollow or depression where the gas emerges1 the flat sheet of flame which is formed when the two streams of gas impinge upon each other obtains a broader base1 and at the same time is preserved from drawing air into its midst4 ,but the chief share of the improvement is due to the alteration in the angle formed by the two channels in the burner-tip4 ,it will be readily apparent that the more obtuse this angle--that is1 the nearer the two streams of gas are to impinging against each other in a horizontal line--the more will the flame tend to spread out1 or the lower the pressure required to obtain any desired spread of flame4 ,it is by taking advantage of this circumstance that ,mr4 ,bray has been enabled to improve the union-jet burner4 ,twenty years ago this burner was usually made with the two channels in the burner-tip placed at an angle of about #fj deg44 ,in ,bray's regulator burner1 introduced in #ahfi1 they were placed at an angle of #ij deg42 with the result of obtaining a more satisfactory flame1 both as regards its appearance and illuminating power4 ,in the special burner1 which was not brought out till #ahgf1 the angle is increased to #abj deg42 thus enabling the necessary spread of flame to be obtained with the gas issuing at a low pressure4 ,another minor improvement in the latter burner consists in making the holes in the burner-tip elliptical instead of circular4 ,,chapter ,,iii4 ,,argand ,,burners4 ,sidenote3 ,the premier gas-burner4 ,the premier position among gas-burners undoubtedly belongs to the ,argand2 and it is from no unwillingness to recognize its claims1 much less from ignorance of its merits1 that ,i have left the consideration of this burner until now4 ,it occupies this honourable position as much by virtue of the importance it has acquired through being accepted by ,parliament as the test burner1 and the peculiar relation in which it consequently stands to other burners1 as for any marked superiority in operation4 ,for while1 in general1 the ,argand gives superior results to other burners1 this is not always the case4 ,there are circumstances and conditions to which the ,argand is quite inapplicable1 and where a simpler and less pretentious burner will give excellent results4 ,indeed1 some of the simple flat-flame burners which we have had under notice have now been brought to such a stage of perfection1 that1 when intelligently used1 they not unsuccessfully rival the ,argand4 ,but it has been in the direction of demonstrating the illuminating power which it was possible to obtain from gas1 and stimulating to the attainment1 by other and simpler burners1 of the same level of excellence1 that the influence of the ,argand has been most beneficial4 ,for1 by reason of its peculiar construction1 and more especially its mode of obtaining the air necessary for combustion1 the ,argand lends itself1 more readily than any other burner1 to the work of investigating and experimenting upon the conditions necessary for economical combustion1 and the development of the highest illuminating power from the gas consumed4 ,in this burner1 the air supply to the flame is under complete control2 and thus one of the chief elements of uncertainty and difficulty which are experienced in dealing with other burners is eliminated4 ,the delivery of gas to different parts of the flame is also more susceptible of variation2 and the results of such variation more fully exposed to observation4 ,the consequence has been that the most remarkable advances in developing improved illuminating power from coal gas have been made with this burner4 ,but after the possibility of obtaining an improved duty from the gas has been demonstrated by means of the ,argand1 and the conditions necessary for its attainment determined1 equally good results have been achieved by other burners4 ,illustration3 ,,plan ,,of ,,glass-,,holder ,,and ,,burner ,,top4 ,,section ,,of ,,burner4 ,,fig4 #ac4--;,,argand ,,burner4 ,in thus showing the benefits to be derived from a more scientific mode of combustion1 and leading the way to the fuller attainment1 by other burners1 of the illuminating power obtainable from the gas1 the ,argand burner has acted as a pioneer in the development of gas lighting4 ,for1 on account of its complexity1 and its delicacy of construction1 this burner has never been1 nor1 indeed1 can ever hope to be generally employed4 ,besides the inconvenience and expense entailed by the cleaning and renewal1 when broken1 of the glass chimney which is indispensable to this burner1 its very perfection as a burner precludes its being adopted under the conditions which appertain to the great majority of situations in which gaslight is required4 ,for while1 under the particular conditions as to pressure of gas1 c41 for which it has been constructed1 the ,argand may give results surpassing any other burner1 a very slight divergence from these conditions is productive of far more damaging results to the illuminating power of the flame than is the case with other and less efficient burners4 ,the cause of this seeming anomaly will be apparent when we come to consider in detail the construction of the ,argand1 and the conditions which must be observed to ensure its satisfactory operation4 ,for the present it will suffice merely to make mention of what appear to be well-established facts--viz41 that the most perfect burners are the least adapted for use under uncertain and varying conditions2 and that in proportion to the efficiency of a burner1 under the conditions for which it has been constructed1 is the injury to the illuminating power of its flame which is experienced when these conditions are departed from4 ,sidenote3 ,what is an ,argand burner8 ,resolved into its simplest form1 the ,argand burner may be said to consist of a hollow ring of metal1 or other suitable material1 provided with the necessary tubes or connections for communicating between its interior and the gas supply1 and perforated on its upper surface with a number of holes for the emission of the gas4 ,through these holes the gas issues in a series of jets1 which immediately coalesce to form one cylindrical sheet of flame4 ,the burner is surmounted1 and the flame enclosed1 by a glass chimney1 which is supported on a light gallery connected with the burner2 the chimney serving the double purpose of shielding the flame from draughts1 or currents of air 7thus enabling the gas to burn uniformly and steadily71 and of drawing upon the surface of the flame the supply of air necessary for its proper and complete combustion4 ,for in the ,argand the air supply is produced under conditions totally different from those which govern its production in all the other burners we have had under consideration4 ,in flat-flame burners1 the quantity of air supplied to the flame is determined by the pressure of the gas2 or1 in other words1 the velocity with which it issues from the burner4 ,in ,argand burners1 on the contrary1 the air supply is obtained quite independently of the pressure at which the gas issues2 and the conditions most effective for the economical combustion of the gas1 and the development from it of the highest illuminating power attainable1 are only secured when the pressure of gas is reduced to a minimum4 ,it has been shown1 in speaking of flat-flame burners1 how the illuminating power of the flames yielded by such burners is injuriously affected by an excess of pressure in the gas1 as it issues into the atmosphere1 causing a too great intermingling of gas and air4 ,with such burners1 however1 some degree of pressure is needed1 in order1 by bringing the flame into contact with sufficient of the oxygen of the air1 to promote the requisite intensity of combustion2 whereas with the ,argand the draught that is produced through the agency of the glass chimney enables the necessary supply of air to be obtained for the support of the flame without adventitious aid from the pressure of the gas4 ,consequently1 one of the chief objects to be aimed at in the construction of the latter burner is to so reduce the pressure of the gas within the burner that it may issue with little or no greater velocity than that due to its own specific lightness4 ,in some of the best ,argands this object is attained very successfully2 and the ingenious devices which have been made use of to gain this end will be duly described in the sequel4 ,but1 in addition to causing the gas to issue from the burner at the minimum of pressure1 it must be delivered evenly and equally at all parts of the ring of holes2 so that there shall not be an excess of gas supplied to one portion of the flame1 and an insufficiency to others4 ,then the area of the opening in the centre of the ring1 through which the air supply is obtained to the inner surface of the flame1 as well as the length and diameter of the glass chimney1 must be so proportioned that the exact quantity of air needed to enable the flame to yield its maximum results shall be drawn upon it4 ,these1 and other equally essential requirements1 have to be taken into consideration1 and provided for1 in constructing an efficient ,argand burner4 ,it is no wonder1 therefore1 that the development of the powers of this burner has taken up so much time and labour and inventive skill2 and the remarkable degree of efficiency to which it has now been brought testifies to the thought and the accurate knowledge of the principles of combustion which have been brought to bear upon it4 ,sidenote3 ,the earliest ,argands4 ,it is1 however1 only within comparatively recent years that its true principles of construction have been at all fully recognized1 as evinced by the burners which have been produced4 ,for a long period1 ,argand burners were made upon wholly empirical and arbitrary rules4 ,during the early years of gas lighting1 the makers of gas apparatus1 and such persons as professed to have a special knowledge of the production and utilization of the new illuminant1 appear to have been ignorant of even the most obvious of the conditions required for the successful working of the burner4 ,in one of the earliest works which appeared relating to gas lighting1#aa we find the ,argand burner described as consisting of two concentric tubes closed at the top with a ring having small perforations1 out of which the gas can issue2 thus forming small distinct streams of light4 ,according to this description1 the burner referred to cannot have been an ,argand in the strictest sense of the word2 but1 in reality1 must have consisted chiefly of a series of single jets placed in a circle1 and surrounded by a glass chimney4 ,but the great improvement in the amount of light developed1 which resulted from bringing the jets of flame closer together1 so as to cause them to coalesce and produce one homogeneous mass of flame1 could not long escape notice2 and accordingly we find that in ,clegg's ,treatise1 which appeared twenty-five years later1 the proper disposition of the holes in the ring1 necessary for the successful operation of the burner1 is clearly recognized4 ,in this work1 speaking of the ,argand burner1 it is remarked 7p4 #aic7 that the distance between the holes in the drilled ring should be so much that the jet of gas issuing from each shall1 when ignited1 just unite with its neighbour4 #aa ,accum's ,treatise on ,gas-,lights4 ,before a really efficient burner could be produced1 there were1 however1 to be successfully encountered other problems1 the precise nature of which was not so clearly apparent as that of the one above referred to2 otherwise their solution would not have been so long delayed4 ,of these1 the most important1 and at the same time the most difficult1 were two--namely1 the right adjustment of the air supply1 and the most advantageous pressure at which to consume the gas4 ,in the earliest ,argands1 not the slightest provision was made for diminishing the pressure of the gas before it was consumed4 ,it was thought that everything had been accomplished that was necessary if the holes for its emission were sufficiently minute to allow of no more than the required quantity of gas passing through them at the extreme pressure at which it was supplied to the burner4 ,the consequence was that the gas1 issuing from the burner at a very high velocity1 became so intermingled with air before it was consumed1 that its flame was excessively cooled2 and only a small fraction of the illuminating power available was developed4 ,then as to the air supply4 ,in nearly every burner produced prior to ,mr4 ,w4 ,sugg's invention of the ,london ,argand in #ahfh1 this was greatly in excess of the requirements2 nor is it to be wondered at4 ,had the supply of air been delicately adjusted1 while yet there was no provision for diminishing the pressure of gas at the burner1 the flame would have been liable to smoke on any sudden increase in the pressure of gas in the mains2 and the annoyance and inconvenience occasioned by a smoking flame were greater drawbacks than the loss of light experienced through having the air supply greatly in excess4 ,thus1 although during this period there were many so-called improved burners brought into notice1 in none of them were these two cardinal requirements in the production of an efficient burner clearly recognized and seriously grappled with2 and1 consequently1 the high level of excellence to which the ,argand is capable of being brought was not attained4 ,,sugg',s ,,argands4 ,sidenote3 ,the ',london' ,argand4 ,the invention by ,mr4 ,w4 ,sugg1 in #ahfh1 of the famous ,london ,argand constitutes an important epoch in the history of gas lighting4 ,prior to that time1 the construction of this class of burners had been carried out in a wholly empirical manner2 and such improvements as had been effected must be looked upon as being rather the fortuitous issues of hap-hazard endeavours1 than as resulting from the acquirement of clearer views as to the conditions to be complied with in order to ensure the successful operation of the burners4 ,the invention of the ,london ,argand was the first earnest attempt to abandon the former chance methods1 and to proceed upon more scientific lines4 ,its construction shows that its inventor possessed a thorough acquaintance with the principles of combustion2 while1 in many particulars1 it exhibits an intelligent discernment1 and a successful application of the precise means required to attain a desired end4 ,in this burner1 the extreme importance of causing the gas to issue at a low pressure is for the first time clearly recognized2 and the manner in which this object is so successfully attained is as simple as it is ingenious4 ,at the entrance to the burner the gas is divided among three narrow tubes1 the combined capacity of which is much smaller than that of the pipe supplying the burner4 ,through these tubes the gas is conducted into a concentric cylindrical chamber 7forming the main body of the burner71 where its rapid flow is checked2 the current1 or swirl1 which it may have acquired1 is subdued2 and the gas comes to a state of comparative rest before it issues into the atmosphere and is consumed4 ,the top rim of this concentric cylinder is pierced with #bd holes1 the aggregate area of which is considerably greater than that of the three supply-tubes2 thus ensuring that the gas shall be delivered at a much lower pressure than that at which it enters the burner4 ,by dividing the gas into three streams1 which enter the cylindrical chamber at equidistant points in its circumference1 the supply is equally distributed throughout the entire ring of holes2 and a flame of even and regular shape is the result4 ,the arrangement by which1 in this burner1 the air supply is obtained and regulated is as noteworthy as are the means adopted for controlling the pressure of the gas4 ,the opening within the circular ring of holes is much smaller than in previous ,argands2 thereby proportionately reducing the quantity of air supplied to the inner surface of the flame4 ,the space between the cylindrical body of the burner and the glass chimney is occupied by a truncated cone of thin metal1 the upper edge of which is on a level with1 and reaches to within a very short distance of the rim of the burner2 while its base rests upon the gallery supporting the chimney4 ,by means of this cone1 all the air entering between the burner and the chimney is directed upon the immediate surface of the flame2 thereby promoting intensity of combustion1 and a higher illuminating power of the flame4 ,then the chimney itself is of such dimensions that1 with the quantity of gas for which the burner has been constructed1 just sufficient air is drawn upon the flame to completely consume the gas by the time the top of the chimney is reached2 a flame of such length as to nearly reach to the top of the chimney1 without smoking1 being the most effective and economical for the quantity of gas consumed4 ,illustration3 ,,fig4 #ad4--,,sugg',s ,,london ,,argand4 7,full ,size47 ,another matter which tended not a little to enhance the results yielded by this burner was an alteration in the material of which the body of the burner was constructed4 ,in previous ,argands1 this had1 in almost every instance1 been metal2 whereas in the ,london burner steatite was employed4 ,how the illuminating power of the flame is affected by the material of which the burner is constructed has been gone into so fully before 7in relation to flat-flame burners71 that it is unnecessary to dwell upon the matter here2 only remarking that as in ,argands the contact surface between the burner and the flame is relatively so much greater than in flat-flame burners1 the cooling of the flame due to this cause is proportionately increased4 ,sidenote3 ,the standard test burner4 ,sidenote3 ,the improved ,london ,argand4 ,so great was the improvement effected by this burner in the illuminating power developed from the gas consumed1 so obvious its superiority to every previous ,argand1 that it was immediately adopted by the ,metropolitan ,gas ,referees as the standard burner for testing ordinary coal gas within the area of their jurisdiction2 and from that time down to the present it has continued to be prescribed in ,acts of ,parliament as the burner to be employed in testing ordinary coal gas1 not only in the ,metropolis1 but generally throughout the ,united ,kingdom4 ,but although1 as the standard test-burner1 the original ,london ,argand can still be obtained1 it has been far surpassed1 in the results yielded1 by a new series of ,argands1 in which the same ingenious inventor has still further applied the principles first put into practice in the former burner4 ,in this newer series of burners1 the details of construction before adopted are modified in two or three particulars2 but without departing from the general principles embodied in the arrangement of the earlier burner4 ,thus the holes in the ring are considerably larger1 while the three supply-tubes remain of exactly the same capacity as before2 by which means the gas is delivered at a much lower pressure4 ,as the increased size of holes necessitates that the cylindrical body of the burner should be of enlarged diameter1 the opening in the centre becomes of greater area than before4 ,were it to remain so1 it would permit too large a quantity of air to be drawn upon the inner surface of the flame2 to obviate which result a metal spike rises in the centre1 reducing the area of the opening1 and proportionately diminishing the quantity of air which would otherwise be admitted at this part of the burner4 ,the arrangement for regulating the air supply to the outer surface of the flame is likewise modified1 but in a different direction4 ,the upper edge of the cone is brought nearer to the rim of the burner1 and slightly curved1 so as to direct the air more completely upon the flame2 while the base of the cone1 instead of extending to the glass chimney in an unbroken surface1 is pierced by a number of holes1 which admit air between the cone and the chimney4 ,the action of this third current of air is to keep the chimney cool1 and to steady the flame2 and1 in addition1 it may be that it provides a supply of air to support and intensify combustion at the upper extremity of the flame4 ,the combined effect of these alterations is to cause the burner to develop from #g to #ab per cent4 more light from the gas consumed1 than is yielded by the original ,london ,argand4 ,sidenote3 ,silber's ,argand burner4 ,the ,silber ,argand1 which is a remarkably efficient burner1 in the main features of its construction is very closely related to ,mr4 ,sugg's later ,argands just described4 ,the air is directed on to the outer surface of the flame1 as in those burners1 by a curved deflector1 of which the upper edge is1 however1 at a higher level than in ,mr4 ,sugg's burners4 ,air is also admitted between the deflector and the glass chimney4 ,the most striking divergence in its construction from that of ,mr4 ,sugg's burners is contained within the opening in the centre of the burner4 ,instead of a solid metal spike1 there is a brass tube1 through which1 as well as between its circumference and the cylindrical body of the burner1 air can enter to feed the inner surface of the flame4 ,in addition to promoting the steadiness of the flame1 it would appear that the air entering through this inner tube supports the combustion of the gas at the tail of the flame4 ,the arrangements for diminishing the pressure of the gas within the burner1 and for ensuring its equable distribution to all parts of the ring of holes1 though quite different1 seem to be scarcely less complete than those employed in the ,london burner4 ,from the nipple which connects the burner to the gas supply1 the gas enters 7by four minute perforations7 into a horizontal chamber1 where its velocity is checked1 and whence it is conveyed into the cylindrical chamber forming the main body of the burner4 ,the very satisfactory performances of the burner 7which are in advance of those of the standard ,argand7 sufficiently attest the correctness of its construction4 ,sidenote3 ,multiple ,argands4 ,for consuming large quantities of gas1 double or treble ,argands are constructed4 ,these consist1 in effect1 of two or three ,argand burners placed concentrically to each other within one chimney4 ,mr4 ,sugg has produced a series of burners of this class1 designed to pass quantities of gas ranging from #ae to #ee cubic feet per hour2 and1 in some instances1 exceeding even the latter figure4 ,these burners1 with ordinary 7#af-;candle7 coal gas1 give a light equal to #d candles per cubic foot of gas consumed2 which is a considerably better result than is afforded by the standard burner4 ,the cause of their yielding results so superior to the ordinary ,argand is found in the circumstance that their flames present a much smaller surface area to the cooling action of the air1 in proportion to the quantity of gas consumed4 ,the arrangement of these burners differs from that of the improved single ,argands1 which have been described1 only in that there are two or more steatite cylinders1 each fed by its own supply-tubes1 and having its own distinct ring of holes2 while the space between the cylinders is so proportioned as to admit no more than the quantity of air required to produce the necessary intensity of combustion4 ,illustration3 ,,fig4 #ae4--,,the ,,douglass ,,argand4 7,a ,a1 ,focal ,plane1 or ,belt of ,strongest ,light47 ,,the ,,douglass ,,burner4 ,the multiple or concentric ,argand invented by ,mr4 7now ,sir7 ,j4 ,n4 ,douglass1 the ,engineer to the ,trinity ,house1 may be mentioned here4 ,this burner is of the type of those last noticed1 but possesses certain peculiar features which give it a distinct claim to novelty4 ,as will be seen by the accompanying illustration1 the concentric cylinders of which the burner is composed terminate at different heights2 their tops forming a regular gradation of steps1 of which the innermost is the highest4 ,these cylinders are of considerable depth1 permitting the gas and air to be heated by contact with their surfaces before the point of ignition is reached4 ,the essential feature of the invention1 however1 is a series of deflectors of peculiar shape1 which1 in addition to directing air on to the surfaces of the flames1 are so formed as to force the outer flame or flames on to the inner flame or flames in the manner illustrated4 ,by this means the flames are concentrated and united into one1 and combustion is quickened2 and1 a greater intensity of heat being thus attained1 the illuminating power is much augmented4 ,when this burner was first brought into notice1 in #ahha1 high hopes were entertained as to its future4 ,the results which it was said to afford1 being far in advance of anything previously obtained from a simple ,argand1 seemed to promise for the burner a speedy and unequivocal success4 ,at the ,north-,east ,coast ,marine ,exhibition1 held in #ahhb1 a burner with ten rings was exhibited1 which was reported to develop1 from #af-;candle gas1 #f candles per cubic foot--a truly remarkable result to be given by so simple a burner4 ,but1 notwithstanding its apparently successful introduction1 the burner has made little or no headway in the direction of its practical application4 ,indeed1 it may almost be said to have faded altogether out of public view4 ,this would seem to imply that there are difficulties in the way of its successful working1 when brought under ordinary conditions1 which were not foreseen at the time of its invention4 ,,chapter ,,iv4 ,,governor-,,burners4 ,sidenote3 ,effects of excessive pressure with ,argand and flat-flame burners4 ,throughout this treatise1 much has been said of the relation which the pressure of gas1 at the point of its delivery from the burner1 bears to the illuminating power of the flame yielded--sufficient to show that the maintenance of a low and equable pressure in the gas supply is one of the conditions most imperative to be observed for the attainment of economy in combustion4 ,ordinarily1 however1 this condition does not obtain at the consumers' burners4 ,the exigencies of distribution require that1 in order to maintain a sufficient supply wherever gas is needed1 a much higher pressure should be kept in the mains than is requisite for developing1 at the burner1 the best results from the gas consumed4 ,moreover1 the pressure at any one point is subject to continual fluctuations from the variations in the consumption of gas going on in the neighbourhood4 ,for instance1 where a number of burners are in operation in a house1 consuming about the exact quantities of gas for which they have been constructed1 when part of them are shut off the gas supply to the remainder is in excess of what is required2 and1 consequently1 the burners do not develop the same proportion of light from the gas consumed as formerly4 ,where a large consumption of gas is suddenly discontinued 7as in the business parts of a town1 when the shops and warehouses are closed71 the increase of pressure that is experienced at the burners which remain in operation is very manifest4 ,the effect of this increase in the pressure of the gas supply is seen in different directions in ,argand and flat-flame burners4 ,in the former1 it causes the flame to smoke1 by permitting more gas to pass through the burner than can be properly consumed2 in the latter1 by cooling the flame below the temperature required for effective combustion1 it reduces1 in proportion to the extent to which it is higher than the original pressure1 the illuminating power developed per cubic foot of gas consumed4 ,sidenote3 ,the gas regulator4 ,seeing that economy in combustion can only be attained under the conditions of an equable pressure1 it becomes necessary to subdue the fluctuations above referred to1 or at least to prevent their reaching the burner4 ,to this end the regulator1 or governor1 is employed4 ,in this instrument1 a bell dipping into1 and sealed in liquid--or else a flexible leather diaphragm--is actuated by the pressure of the entering gas1 and so connected with a valve as to reduce the area of the opening which permits gas to enter the instrument in proportion to the pressure of gas at the inlet2 by which means an equable pressure is maintained at the outlet1 no matter what the quantity of gas which is being consumed1 or how the pressure may vary in the inlet-pipe4 ,by the aid of a governor1 fixed on the service-pipe at the entrance to a building1 the pressure of gas at the various burners is rendered fairly uniform2 yet1 even then1 perfect equality of pressure is not obtained4 ,the slight friction which the gas experiences in flowing through the pipes causes the burners to be supplied at somewhat lower pressures1 the farther they are removed from the burner4 ,and1 again1 owing to its low specific gravity1 gas tends to gain in pressure with an increased elevation2 each rise of #aj feet adding about #a-ajth of an inch to its pressure4 ,from this cause a higher pressure is experienced in the upper than in the lower rooms of a building4 ,this peculiarity was observed at an early period in the history of gas lighting2 as ,clegg mentions that1 in cotton-mills1 check-taps were employed to regulate the pressure of gas at each floor4#ab ,in order1 therefore1 to obtain the desired regularity of pressure in the gas supply1 governors must be employed for each storey2 or1 what is better still1 each burner must have its own separate governor4 ,and this brings us back to the subject with which we are more closely concerned4 #ab ,clegg's ,treatise on ,coal ,gas1 #ast ,ed41 p4 #aig4 ,the governor-burner1 as its name implies1 consists of a governor1 as described above 7but1 of course1 on a smaller scale7 combined with a gas-burner2 the governor being adjusted so as1 whatever excess of pressure there may be in the gas-supply pipes1 to permit only the quantity of gas to pass which the burner is intended to consume4 ,obviously1 the principle herein contained is capable of receiving numerous applications4 ,it can be1 and is applied with equal success to ,argand and flat-flame burners2 while the modifications which obtain in the manner of constructing the regulating portion of the apparatus are almost as numerous and as varied as are the burners themselves4 ,as the main features exhibited by one are common to all1 it is unnecessary to go into the details of their several constructions4 ,it will suffice to take two or three of the most successful1 or the best known1 as representatives of the whole4 ,sidenote3 ,giroud's ,rheometer4 ,among the first in order of time--and still retaining no unworthy position in order of merit--is the rheometer1 or flow-measurer1 of ,m4 ,giroud4 ,in this instrument a light metal bell is sealed in glycerine contained in a cylindrical case2 the bottom of this latter containing the inlet-pipe1 screwed for connecting to the ordinary fittings1 while from the centre of its cover rises a tube leading to the burner4 ,the bell is pierced by a small hole for the passage of the gas1 and is surmounted by a cone-shaped projection1 which constitutes the valve of the instrument4 ,as the pressure of the entering gas lifts the bell1 it causes this cone-valve to enter the mouth of the tube leading to the burner2 reducing the area of the opening in proportion to the pressure of gas acting upon the under side of the bell1 and so permitting only the required quantity of gas to pass to the burner4 ,it might be thought that the presence of liquid would constitute an objection to the use of the instrument2 but1 as glycerine does not evaporate1 when once the instrument is fixed and properly adjusted1 it needs no further attention4 ,with an excessive initial pressure1 there is1 however1 a liability of the gas to bubble through the sealing liquid1 and so destroy the efficiency of the instrument2 but this might be obviated by increasing the depth of the bell1 and so giving it a greater seal4 ,the instrument is very reliable for the purpose which it is intended to fulfil2 delivering1 through a considerable range of pressure beyond that required to raise the bell1 the exact quantity of gas for which it has been adjusted4 ,it may be added that the rheometer has an advantage over many instruments of its class1 in that it presents so little obstruction to the downward rays of the flame4 ,illustration3 ,,fig4 #af4--;,,giroud',s ,,rheometer4 ,sidenote3 ,sugg's ,christiania governor-burner4 ,mr4 ,william ,sugg1 in his regulator or governor1 adopts an entirely different arrangement to the foregoing4 ,the valve is placed at the inlet of the governor2 and not at its outlet1 as in the instrument just described4 ,instead of a metal bell1 a diaphragm of thin and very flexible leather is employed1 which is raised by the pressure of the entering gas1 and1 in turn1 actuates the valve2 closing the entrance to the governor in proportion to the pressure of gas acting upon it4 ,the orifice communicating between the under and the upper side of the leather diaphragm is controlled by a screw1 whereby the quantity of gas delivered to the burner can be regulated according to requirements2 but when once it has been adjusted to give any desired pressure of gas at the burner1 this pressure will be strictly maintained1 no matter with what excess of pressure 7within reasonable limits7 the gas may be supplied to the instrument4 ,the improved ,london ,argands produced by ,mr4 ,sugg 7the details of the construction of which have been already described7 are too delicately adjusted to be applied with advantage directly to the ordinary consumer's gas-fittings1 or wherever any variation in the pressure of the gas supply is likely to be experienced4 ,however1 with the addition to them of the above governor1 their use becomes as easy and simple as that of other burners2 and thus the gas consumer is enabled to obtain the benefit of the most improved apparatus without being called upon to exercise the constant care and attention which1 without the aid of the governor1 would be necessitated4 ,besides being applied to ,argands1 this governor is successfully applied by its inventor to his flat-flame burners4 ,in conjunction with a simple steatite burner of the latter class1 it has received a very extended application1 under the name of the ,christiania governor-burner4 ,sidenote3 ,sugg's ,steatite-float governor-burner4 ,recently1 however1 a new type of governor1 for application to burners1 has been brought out by the same manufacturer1 the construction of which is very different to that of the instrument referred to above2 and as it is somewhat simpler in its details1 and withal appears to be cheaper in construction1 it seems destined to supersede the former instrument4 ,in this new governor1 instead of a leather diaphragm1 there is a bell 7or float7 of steatite1 which is free to move1 in the manner of a piston1 within an inner cylindrical chamber contained within the outer case of the instrument4 ,attached to the centre of the float1 and on its upper surface1 is a tube sliding within another tube of somewhat larger area2 the latter forming a continuation of the inner cylindrical chamber4 ,the smaller tube is open at both ends1 and thus communicates from below to above the float2 the outer tube is closed at the top1 but has an orifice in its side4 ,the action of the instrument is as follows3--,the gas1 entering below the float1 passes through the inner tube to the upper part of the cylindrical chamber1 and thence1 through the orifice in the outer tube1 to the burner4 ,as the pressure of the entering gas exceeds that required to overcome the weight of the float1 the latter is raised2 the tube which is attached to it being propelled farther into the outer tube in which it slides1 and1 in so doing1 partially closes the orifice in the side of the latter4 ,in this way1 according to the pressure of the gas acting upon the under side of the float1 the area of the opening through which it must flow to get to the burner is reduced2 and so the quantity of gas which issues from the burner remains the same under all pressures above that required to actuate the float4 ,the instrument appears to be as reliable as it is simple1 and to contain few parts calculated to get out of order2 but1 of course1 whether or not it will retain its good qualities after long-continued use can only be proved by experience4 ,illustration3 ,,fig4 #ag4--,,sugg',s ,,steatite-,,float ,,governor4 ,sidenote3 ,peebles's needle governor-burner4 ,sidenote3 ,efficiency of the needle governor-burner4 ,another instrument of this class--the last which ,i shall notice--is ,peebles's needle governor-burner4 ,for simplicity combined with remarkable efficiency1 it is undoubtedly ahead of all its compeers4 ,somewhat similar in principle to ,giroud's rheometer1 it differs from that instrument in many of the details of its construction2 and while dispensing with the use of liquid1 maintains equal efficiency in operation4 ,it was described as follows by ,dr4 ,w4 ,wallace1 in a lecture on ,gas ,illumination1 delivered before the ,society of ,arts in ,january1 #ahgi3ac--;,in a little cylinder stands a so-called needle1 on the point of which rests a flanged cone of exceedingly thin metal4 ,at one side of the cylinder there is a small tube leading away the gas1 and the orifice of which is influenced in area by the action of the cone4 ,the instrument1 by means of a screw leading into the side tube1 can be made to deliver any desired number of cubic feet1 which it does with surprising accuracy1 provided that the pressure of the gas is not less than #f-ajths of an inch4 ,as to the efficiency of the instrument1 ,dr4 ,wallace proceeded to state3--,in trials that ,i have made1 ,i have not found the variations of volume at different pressures to exceed #a per cent4 ,for situations where this extreme nicety of operation is not absolutely essential1 or where the rate of consumption is to be invariable1 the instrument is constructed in a somewhat modified and simpler form4 ,the small tube on the side of the instrument is dispensed with1 and the gas permitted to pass through perforations in the lower part of the cone4 ,with this alteration there is a nearer approach to the construction of the rheometer2 but1 as in that instrument1 there is no provision for altering the rate of consumption to suit different circumstances4 #ac ,see ,journal of ,gas ,lighting1 ,vol4 ,,xxxiii41 p4 #afb4 ,illustration3 ,,fig4 #ah4--,,peebles',s ,,needle ,,governor4 ,,chapter ,v4 ,,regenerative ,,burners4 ,sidenote3 ,temperature of a gas flame4 ,as was remarked in the introduction to this treatise1 recent years have witnessed a very considerable advance in the construction of gas-burners1 and in the amount of light capable of being developed from each cubic foot of gas consumed4 ,undoubtedly the most noticeable feature of this advance is the successful application of the regenerative1 or1 as it would be more appropriately designated1 recuperative system4 ,briefly stated1 this consists in utilizing the heat of the products of combustion from the gas flame 7which otherwise would be dissipated into the atmosphere7 to raise the temperature of the gas before it is ignited2 and1 likewise1 of the air necessary for combustion4 ,the temperature of an illuminating gas flame is usually estimated to be between #bjjj deg4 and #bdjj deg4 ,fahr42 and as the products of combustion must leave the flame at a temperature little1 if at all1 inferior to the former figure1 it must be evident that there is an ample margin of heat for employment in this direction4 ,a considerable proportion of the large amount of heat conveyed by those products of combustion which1 under ordinary circumstances1 is imparted to the surrounding atmosphere--often elevating its temperature to an unnecessary and prejudicial extent--is1 by this method1 returned to the flame2 intensifying the process of combustion1 and augmenting1 in a remarkable degree1 the illuminating power developed from the gas consumed4 ,thus the ultimate effect of the operation is to produce a concentration of heat in the flame1 and the conversion of superfluous heat into beneficial light4 ,within a comparatively recent period1 the utility of this process was strongly disputed2 and it was stoutly maintained1 by many persons1 that as the immediate effect of ignition was to cause a temperature of more than #bjjj deg4 ,fahr4 to be attained1 the heating of the gas and air prior to their combustion could produce little or no beneficial effect upon the illuminating power of the flame4 ,however1 the falsity of this view of the case is conclusively demonstrated by practical experiment2 the remarkably high results yielded by burners that have been constructed upon the regenerative system sufficiently attesting the correctness of the principles upon which they are founded4 ,although1 in general1 both the gas and air supplies are heated1 it is chiefly due to the latter that the beneficial effect noticed is produced2 and this for two reasons4 ,first1 because the quantity of air is so much greater than the gas it is required to consume2 being1 at the nearest approach to theoretical perfection1 fully six times its volume4 ,second1 because four-fifths in volume of the air consists of inert nitrogen1 which does not contribute anything to the heat of the flame1 but1 when applied in its normal1 cold condition1 abstracts no inconsiderable proportion of heat from it4 ,yet the heating of the gas itself is not without very appreciable influence4 ,in an ordinary gas flame there is always an area of non-illumination around1 and extending to a variable distance from the burner head4 ,this is caused partly by the conduction of heat from the flame by the burner2 but1 in a greater degree1 by the cooling action of the issuing stream of cold gas1 as is shown by its extending farther from the burner in proportion to the pressure or velocity with which the gas issues4 ,the prejudicial effect due to the former is obviated to a great extent by constructing the burner of steatite1 or other non-conducting material4 ,to remedy the latter1 nothing will avail but the heating of the gas supply4 ,sidenote3 ,effects of heating the gas and air4 ,the effect of heating the gas is to enlarge the area of the illuminating portion of the flame1 and1 in a minor degree1 to enhance the intensity of incandescence to which the carbonaceous particles are raised4 ,when the gas issues from the burner at a temperature little inferior to the temperature of ignition1 the hydrocarbons it contains are immediately decomposed2 the liberated particles of carbon are raised to the temperature of incandescence2 and the illuminating area of the flame is extended downwards1 even to the surface of the burner4 ,the heating of the air operates chiefly to produce and maintain a more elevated temperature of the flame2 and1 in this manner1 contributes to the development of a higher illuminating power from the same area of flame4 ,in the case of ordinary gas flames1 the cold atmosphere by which they are surrounded1 by abstracting heat from the flame1 prevents the most favourable conditions for the development of light from being attained4 ,when1 however1 the air immediately surrounding the flame has been previously heated1 the particles of carbon 7the incandescence of which furnishes the desired illuminating power7 attain to a much more exalted temperature2 and1 consequently1 give out a greater degree of light4 ,but there is yet another direction in which the prior heating of the air supply contributes to the development of improved illuminating power4 ,being heated1 its density is lowered2 so that in any given volume of air there is less weight of oxygen than when cold4 ,the consequence is that as less oxygen is presented to a given surface area of flame1 the separated particles of carbon remain for a longer period of time in the incandescent condition before being entirely consumed4 ,thus there are three distinct results produced by heating the gas and air before combustion--namely1 first1 the particles of carbon are liberated earlier in the flame2 second1 they are raised to a more exalted temperature2 and1 third1 they remain for a longer time in the incandescent condition4 ,the combined effect of all three is the improved illuminating power developed from the gas consumed4 ,illustration3 ,,fig4 #ai4--;,,bowditch',s ,,regenerative ,,gas-,,burner4 ,sidenote3 ,bowditch's regenerative burner4 ,so far back as the year #ahed1 the principle of heating the air supply to an ,argand burner1 by means of waste heat from the flame1 was partially applied1 with some success1 by the ,rev4 ,w4 ,r4 ,bowditch1 ,m4,a41 of ,wakefield4 ,mr4 ,bowditch's burner1 which is shown in the accompanying diagram1 contained1 in addition to the ordinary chimney1 an outer glass chimney1 which extended for some distance below the inner one1 and was closed at the bottom2 so that all the air needed to support the combustion of the gas was required to pass down the annular space between the chimneys1 and in its passage became intensely heated by contact with the hot surface of the inner chimney1 as well as by radiation from the flame itself4 ,this burner contained many defects4 ,amongst others1 the inner chimney could not long withstand the intense heat to which it was subjected1 and1 in consequence1 had to be frequently renewed2 the heating of the air was not effected solely by the products of combustion1 but1 perhaps in a greater degree1 by the abstraction of heat from the flame itself2 while1 at best1 this heating was but partial4 ,yet1 these defects notwithstanding1 the burner showed very clearly the beneficial results attending even a partial application of the principle2 as1 in the illuminating power it developed from the gas consumed1 a clear gain of #fg per cent4 over the ordinary ,argand burner was obtained4 ,although the drawbacks connected with the construction of ,mr4 ,bowditch's burner prevented its ever receiving general1 or even extensive adoption1 its simplicity has gained for it the distinction of being freely copied by so-called inventors of a later day4 ,sidenote3 ,invention of the ,siemens regenerative burner4 ,it was left to ,herr ,friedrich ,siemens1 of ,dresden1 to produce a burner which1 while applying the principle of regenerative heating in the most scientific and complete manner1 should also be adapted to the ordinary conditions of gas lighting4 ,after much experimenting on the subject1 a burner embodying the essential features of the regenerative system was invented by this gentleman in #ahgi2 and so great was the advance which its performances manifested over anything previously attained1 so wide the prospect of further achievements which was opened out1 that it may fairly be said to have inaugurated a new era in gas illumination4 ,in this burner the products of combustion were made to give up a considerable portion of their heat to the gas and air1 as the latter passed to the point of ignition2 the flame itself not being called upon to contribute in any degree to this result4 ,although1 as was but natural1 the first attempts towards the construction of such a burner were very crude1 and but partially successful in their results1 the inventor persevered in his endeavours to work out his ideas into practical and thoroughly satisfactory shape4 ,it was not until after it had gone through many modifications that the burner acquired the peculiar form which now distinguishes it1 and attained to its present stage of perfection4 ,before proceeding to describe an example of the burner as now constructed1 it is necessary to state that the principles embodied in ,herr ,siemens's invention are equally well adapted--and1 indeed1 are applied with equal success--to the construction of flat-flame and ,argand burners2 but as the distinctive features of the invention are common to both classes of burners1 it will be quite sufficient to describe in detail one of the latter type4 ,a prominent feature in the appearance of the ,siemens burner1 as will be seen from the annexed illustration1 is a large metal chimney1 for creating a draught to carry away the products of combustion4 ,the entrance to this chimney is situated a little above the apex of the flame2 but there is a branch flue connecting the main chimney with the interior of the burner4 ,the body of the burner is of metal1 and its interior is divided into three concentric chambers4 ,of these1 the innermost is open at the top1 and is surmounted by a porcelain cylinder1 which1 when the gas is lighted1 is surrounded by the flame4 ,this chamber is closed at the bottom1 but communicates at the side with the before-mentioned branch tube1 or flue1 leading to the main chimney4 ,the intermediate chamber communicates1 at its lower extremity1 with the gas supply2 and terminates1 a short distance from the top of the burner1 in a number of small metal tubes1 which convey the gas to the point of ignition4 ,the outer chamber is open both at top and bottom1 and is for conveying air to support the combustion of the gas4 ,in order to promote greater intensity of combustion1 there is a notched deflector at the summit of the latter chamber1 and another on the lower part of the porcelain cylinder1 which cause the air to impinge more directly upon both sides of the flame4 ,there is also an arrangement for introducing air between the outer casing of the air chamber and the glass chimney which encloses the flame2 its object being to keep the chimney cool4 ,illustration3 ,,elevation4 ,,enlarged ,,section ,,of ,,combustion ,,chambers4 ,,fig4 #bj4--,,siemens',s ,,regenerative ,,gas-,,burner4 ,sidenote3 ,action of the ,siemens burner4 ,the action of the burner is as follows3--,when the gas is ignited at the ring of tubes1 the heated air and products of combustion1 which rise from the flame1 create a draught in the main chimney4 ,through the communication established by means of the lateral flue1 a partial vacuum1 or area of low pressure1 is induced in the innermost chamber of the burner1 and within the porcelain cylinder which surmounts it4 ,as the flame terminates close to the mouth of the latter1 the greater portion of the products of combustion1 instead of going into the main chimney1 are sucked into the porcelain cylinder2 and thus a current is set up through the interior of the burner1 and by the lateral flue1 to the main chimney4 ,the heat carried away by the products of combustion is communicated1 through the walls of the chambers1 to the entering gas and air2 and by this means the latter are heated to a very high temperature before they issue from the burner and are consumed4 ,the consequence is that a much greater intensity of combustion is maintained2 the carbon particles are separated earlier in the flame1 and are raised to a more exalted temperature2 and the ultimate effect is a higher yield in illuminating power per cubic foot of gas consumed4 ,independent tests by various experienced photometrists have conclusively shown that a light equivalent to that from #e to #f candles is obtained per cubic foot1 from gas which1 in the standard ,london ,argand1 yields a light of only from #c to #c-a_/b candles4 ,sidenote3 ,defects of the ,siemens burner4 ,while the advantages of the ,siemens burner are many and obvious1 it is not without its disadvantages4 ,these partly arise from causes connected with the very observance of the conditions necessary to secure the efficiency of the burner4 ,with every advance in the more efficient operation of gas-burners1 increased care and attention are demanded in their employment1 in order to obtain the benefits they are calculated to yield4 ,indeed1 it would almost appear that the nearer the approach to perfection which is made in the construction of a burner1 the greater must be the drawbacks to its general adoption4 ,thus1 in the burner under notice1 if the gas supply is allowed to become in excess1 the tail of the flame enters the porcelain cylinder1 and soot is deposited in the interior of the burner2 obstructing the passages1 and impairing the burner's action4 ,then1 to cause the burner to yield its highest results1 it is necessary that the air supply be accurately adjusted to the quantity of gas being consumed4 ,to this end the entrance to the air chamber1 at the bottom of the burner1 is covered by a perforated semi-circular cup1 by turning which the quantity of air entering the burner can be increased or diminished as required4 ,moreover1 the bulky construction of the burner1 with its accompaniment of chimney and flue1 and its complicated arrangement of tubes and chambers1 imparts to it a somewhat clumsy and inelegant appearance1 which is calculated to impair the favour with which its remarkable performances cause it to be regarded4 ,but these drawbacks are far outweighed by the undoubted advantages conferred by the burner--in improved illumination combined with economy of combustion1 and the facilities it affords for securing perfect ventilation4 ,encouraged by the success of ,herr ,siemens1 other inventors have followed in his footsteps2 with the result that there are now a variety of burners before the public1 embodying the same principles1 but differing in the details of their construction and in the measure of their efficiency4 ,of these may be mentioned ,grimston's1 ,thorp's1 and ,clark's2 and without describing in detail the construction of the several burners 7of which further particulars will be found in the ,register of ,patents in the ,journal of ,gas ,lighting#ad71 it must suffice to refer to the salient points and distinctive features of each4 #ad ,see ,vol4 ,,xl41 pp4 #ghf1 #iej2 and ,vol4 ,,xlii1 p4 #hcf4 ,sidenote3 ,grimston's regenerative burner4 ,grimston's burner 7shown on the next page7 consists1 in effect1 of an ,argand burner turned upside down2 the gas issuing from the bottom ends of a number of small tubes placed in a circle4 ,the jets of flame--first directed downwards from the mouths of these tubes--by a conoidal deflector in the centre of the ring1 are caused to spread outwards1 and assume a horizontal direction2 and by their amalgamation with each other a continuous sheet or ring of flame is produced4 ,the horizontal direction of the flame is maintained by its passing underneath a metal flange1 faced with white porcelain1 or other refractory material2 the supply of gas being adjusted so that the flame just terminates at the outer edge of this flange4 ,before entering the chimney1 the products of combustion are caused to flow through a number of vertical tubes contained in a cylinder1 which is concentric to an inner cylinder containing the gas-supply tubes4 ,the outer cylinder is traversed by the air needed for the support of combustion1 which is to become heated before reaching the point of ignition2 and in order the more completely to enable the products of combustion to impart their heat to the entering air1 the cylinder is further intersected by strips of wire gauze1 which pass around and between the tubes 7see fig4 #bb1 on next page74 ,by these means the air is intensely heated2 and1 passing among the narrow burner tubes through which the gas is conveyed1 gives up a portion of its heat to the latter before the point of ignition is reached4 ,thus1 in a very simple manner1 both air and gas are raised to a considerable temperature before combustion takes place4 ,with regard to the efficiency of the burner1 at the exhibition of gas appliances held at ,stockport in #ahhb 7where a gold medal was awarded to it1 as well as to ,thorp's burner1 to be referred to hereafter71 with a consumption per hour of #i4hd cubic feet of #ag4e candle gas1 an illuminating power of #fj4fg candles was obtained 7equal to #f4af candles per cubic foot72 while1 on another occasion1 when the burner was consuming #h4id cubic feet per hour1 an illuminating power of #ea4e candles 7equal to #e4gf candles per cubic foot7 was obtained from gas of the same quality4 ,it is claimed for this burner that equally good results are obtained with small sizes as with large2 and this1 if borne out in actual practice1 should go far towards ensuring the success and extensive adoption of the burner4 ,illustration3 ,,fig4 #ba4--;,,grimston',s ,,regenerative ,,gas-,,burner4 ,illustration3 ,,fig4 #bb4--;,,grimston',s ,,burner4 ,,plan1 ,,showing ,,regenerating ,,arrangement4 ,illustration3 ,,fig4 #bc4--,,thorp',s ,,regenerative ,,gas-,,burner4 ,sidenote3 ,thorp's regenerative burner4 ,thorp's burner produces a cylindrical flame1 like that of the ,argand1 but without the aid of a glass chimney which is a necessary adjunct to the latter burner4 ,by means of a deflector on the inner side of the flame1 the latter is made to curve outwards and assume a somewhat convex form1 so as to obviate the shadow which otherwise would be cast by the gas chamber at the bottom of the burner4 ,above the flame is a cylindrical chimney1 divided by a vertical partition into two concentric chambers1 which are intersected by a series of metal gills1 or projections1 continued through both chambers4 ,the outer chamber is for conveying away the products of combustion2 the inner one for the passage of air to feed the flame2 while down the centre of the inner chamber there passes a tube conveying the gas to the point of ignition4 ,the hot products of combustion pass up from the flame through the outer chamber1 and give up the greater portion of their heat to the projections2 by which it is conducted into the inner chamber1 and transferred to the incoming air4 ,a common imperfection of regenerative burners is that1 in consequence of the diminished rate at which the gas flows through the burner when expanded by heat1 when starting the burner the gas must be only partially turned on1 and the quantity gradually increased as the burner becomes heated2 thus necessitating considerable attention4 ,to prevent the need for this attention1 there is in ,thorp's burner an ingenious contrivance for automatically regulating the quantity of gas admitted to the flame4 ,the central gas-tube1 which is referred to above1 contains a brass rod1 fixed at one end1 and at the other connected to a valve controlling the quantity of gas that enters the tube4 ,at first1 when the gas is lighted1 this valve is almost closed2 but as the rod becomes heated it elongates1 gradually opening the valve until the full quantity of gas is admitted which the burner is intended to consume4 ,at the ,stockport exhibition1 ,thorp's burner was tested with the following results1 as recorded in the ,judges' report4 ,after it had burned about two hours1 it gave an illuminating power of #ahc standard candles1 while burning #bg cubic feet of gas per hour 7equal to #f4gg standard candles per cubic foot71 with gas of #c4e candles per cubic foot4444 ,in another experiment with the same quality of gas1 after burning half an hour it yielded1 under similar conditions1 #aed candles with a consumption of #be4bi cubic feet per hour1 which gave an illuminating power of #f4jb candles per cubic foot4 ,sidenote3 ,clark's regenerative burner4 ,there is nothing in ,clark's burner that calls for special notice4 ,in its main features it appears to be constructed upon similar lines to ,grimston's burner1 although the coincidence is doubtless only accidental4#ae ,it must1 however1 be added that in the details of its construction it is much simpler than the latter burner2 and certainly it appears to lose very little in efficiency from its greater simplicity1 as the following extract from a report by ,mr4 ,f4 ,w4 ,hartley1 the well-known photometrist1 will show3--,with a consumption rate of #e4c cubic feet of gas per hour1 the amount of light yielded horizontally was equal to #bi4gi times that of a standard candle4 ,the light yielded per cubic foot of gas burned per hour was therefore equal to #e4fb times that of a standard candle4 ,and the amount of light delivered immediately downwards is said to be very sensibly greater than the amount of light delivered horizontally4 ,like the ,grimston burner1 it is of the inverted ,argand form2 the gas issuing from a chamber at the bottom of a tube which descends through the centre of the burner4 ,the products of combustion escape through a chimney2 and in so doing give up a portion of their heat to the entering air1 which is conveyed to the point of ignition through horizontal tubes that intersect the chimney4 ,the burner is enclosed in a suitable lantern1 the lower half of which consists of a semi-globular glass2 a similar arrangement being adopted in connection with the ,grimston and ,thorp burners4 #ae ,in justice to ,mr4 ,clark it should be mentioned that1 since the above appeared in the ,journal of ,gas ,lighting1 the attention of the writer has been called to the fact 7which had been overlooked by him7 that ,clark's patent was taken out some months before that of either ,grimston or ,thorp4 ,illustration3 ,,fig4 #bd4--;,,clark',s ,,regenerative ,,gas-,,burner4 ,the three burners last mentioned have not been before the public sufficiently long to enable a reliable opinion to be formed as to their value in actual and prolonged use4 ,although there is no reason for supposing that such will occur in the present instance1 it so often happens that the results indicated by apparatus in the experimental stage1 or while still under the control of the inventor1 are not borne out in practice1 that it would be unwise to express any decided opinion as to their ultimate worth from existing information4 ,it is1 however1 to be earnestly hoped that the marked favour with which they have been received will not be impaired on improved acquaintance2 but that further experience will justify the anticipations that have been excited by the excellent performances of the burners hitherto1 and demonstrate at once their durability and real usefulness4 ,since writing the above1 considerable activity has been shown by inventors in producing new burners upon the regenerative principle1 or in improving upon existing models4 ,of course1 as yet it is too early to arrive at a satisfactory estimate of their actual value or relative worth2 but it may be hoped that1 from the increased attention being devoted to the subject1 some real and practical results will flow1 by which the gas-consuming public will be the gainers4 ,so far1 the most promising of this class of burners that has been brought into actual use1 since the introduction of the ,siemens burner1 is the one represented below4 ,illustration3 ,,fig4 #be4--;,,bower ,,and ,,thorp',s ,,regenerative ,,gas-,,burner4 ,it is a modification1 in the direction of greater simplicity1 of ,thorp's former burner1 illustrated and described on p4 #fi of this treatise2 and as its construction is based upon the same lines as that burner1 further description is not required4 ,,chapter ,,vi4 ,,incandescent ,,burners4 ,a review of gas-burners would scarcely be complete without some reference to the incandescent burners of ,m4 ,clamond and ,mr4 ,lewis4 ,although their dependence upon an artificially produced blast or current of air removes them from the list of appliances applicable to ordinary conditions1 the remarkable results which they afford1 not less than their originality1 demand for them at least a passing notice4 ,the production of light by the agency of these burners is brought about in a manner altogether different1 and is due to quite other causes than those which are concerned in the production of an ordinary illuminating gas flame4 ,in the latter case1 the illuminating power developed is solely due to the hydrocarbons contained in the gas1 which are decomposed by the heat of the flame1 the separated carbon being raised to a white heat4 ,in the former1 the illuminating power is not obtained directly from the gas2 but advantage is taken of the heat of the flame1 enhanced by the application of a blast of air1 to raise to incandescence some refractory foreign material1 which latter is thus made to give out light4 ,in the ,clamond burner this refractory substance is a basket composed of magnesia1 spun into threads2 in the ,lewis burner it is a cage of platinum wire4 ,to the unthinking reader it may perhaps appear somewhat surprising that results so remarkable as are yielded by these burners should be obtained1 while disregarding1 as a source of light1 the hydrocarbons contained in gas1 and employing them1 in common with the other constituents1 solely as a source of heat4 ,an explanation1 however1 is readily forthcoming4 ,as was shown in a former part of this treatise1#af the great bulk of ordinary coal gas consists of constituents which1 in the act of combustion1 produce considerable heat1 but scarcely any light2 the illuminating power developed in an ordinary gas flame being almost wholly dependent upon the very small proportion of heavy hydrocarbons which the gas contains4 ,thus1 the quantity of heat-producing elements contained in the gas being quite disproportionate to the light-yielding hydrocarbons1 there is always produced1 in an ordinary gas flame1 more heat than is necessary for effectively consuming the free carbon1 which is liberated in the flame by the decomposition of the heavy hydrocarbons4 ,this is shown by the fact that coal gas can usually be naphthalized--that is1 impregnated with the vapour of naphtha--to a considerable extent before the limit of effective combustion is reached4 ,the object aimed at in the incandescent burners about to be described is to utilize1 in the development of illuminating power1 the combined heat produced by the combustion of all the constituents of the gas4 ,to this end the heat of combustion is brought to bear upon1 and caused to raise to incandescence1 some refractory material1 extraneous to1 but brought within the operation of the flame4 #af ,see ,chap4 ,,ii41 p4 #ba4 ,sidenote3 ,effect of injecting a blast of air into a gas flame4 ,a further explanation of the superior results yielded by these burners may be found in the employment of an artificial blast or current of air4 ,indeed1 without some such arrangement the desired end could not be attained4 ,the heat developed by the unaided flame is diffused over too wide an area to raise the temperature of the heated substance to the necessary degree of incandescence to enable it to give out sufficient light4 ,by injecting a current of air into its midst1 the flame is condensed into a smaller compass2 and is brought to bear more directly upon the precise locality where its heat may be most effectively employed4 ,thus1 although the total quantity of heat developed remains exactly the same as before1 it is concentrated upon a smaller surface of the refractory substance2 and the latter is consequently more intensely heated1 or1 in other words1 raised to a more exalted temperature4 ,the very superior illuminating power which is thereby obtained is due to the circumstance that the quantity of light yielded by an incandescent body increases in a higher ratio than the temperature to which it is raised4 ,sidenote3 ,lewis's incandescent gas-burner4 ,proceeding now to describe the burners4 ,the one invented by ,mr4 ,lewis 7various forms of which are illustrated on the next page7 consists of an upright tube1 connected at its base to the gas supply1 and surmounted by a cap or cage of platinum wire gauze2 which latter constitutes a combustion chamber1 as it is there that the mixture of gas and air is consumed4 ,into the lower part of the upright tube the nozzle of an air-pipe is inserted1 through which a supply of air can be injected1 under pressure1 into the burner1 after the manner of a blowpipe4 ,there are also small branch tubes leading into the upright gas-tube1 and open to the atmosphere4 ,through these an additional quantity of air enters the burner2 being drawn or sucked in by the agency of the main current1 which flows through the upright tube4 ,the resemblance to an ordinary ,bunsen burner is1 therefore1 very close4 ,the mixture of gas and air thus produced1 when ignited1 burns at the platinum cap2 the heat which is developed causing the latter to become highly incandescent1 and so to give out a brilliant light4 ,to prevent the conduction of heat from the incandescent platinum1 through the upright tube1 a non-conducting material--such1 for instance1 as steatite or porcelain--is interposed between the gauze cap and the metal tube4 ,illustration3 ,,fig4 #bf4--,,lewis',s ,,incandescent ,,gas-,,burner4 ,the light produced by this burner is said to approximate more closely to daylight than that yielded by an ordinary gas flame 7the colours of textile fabrics1 for instance1 being shown as well by its aid as by daylight72 while1 on account of its resulting from the incandescence of a fixed body1 instead of being emitted from a flame1 it is unaffected by a gust of wind1 and maintains perfect steadiness under every condition of weather4 ,the illuminating power developed is stated to be equal to #e standard candles per cubic foot of gas consumed4 ,sidenote3 ,clamond's incandescent gas-burner4 ,m4 ,clamond's burner1 which is shown in fig4 #bg1 is a much more complicated apparatus than the preceding one1 and not so easily described2 but its main features may be briefly enumerated as follows3--,the air 7which1 as in ,mr4 ,lewis's burner1 is supplied under pressure7 is divided1 as it enters the apparatus1 into two portions4 ,one portion is at once mixed with the gas2 the remainder being conveyed1 through a peculiarly constructed tube composed of small pieces of refractory material1 to the combustion chamber1 or wick1 as it is termed1 of the burner4 ,this wick is a small conical basket1 made of a kind of lacework of spun magnesia1 which1 when raised to incandescence by the heat produced by the combustion of the gas1 furnishes the desired illumination4 ,the mixture of gas and air is subdivided1 by a distributor1 into two portions1 one of which goes direct to the magnesia wick1 there to be burnt1 while the other is distributed among a number of tubes1 forming so-called auxiliary burners1 the flames of which are utilized to heat the chief air supply2 being directed upon the sides of the before-mentioned tube of refractory material1 through which it is conveyed4 ,by this means the air is raised to a very high temperature 7#ajjj deg4 ,c41 or #ahjj deg4 ,fahr41 it is said7 before it impinges upon the flame4 ,the result is the production of a most intense heat within the magnesia basket2 the latter being raised to brilliant incandescence1 and so developing a high illuminating power4 ,illustration3 ,,fig4 #bg4--;,,clamond',s ,,incandescent ,,gas-,,burner4 ,the magnesia basket must be renewed after being in use a period of from #dj to #fj hours1 as it gradually deteriorates by the action of the intense heat to which it is subjected2 but as the cost is said to be insignificant1 this should not be a great drawback4 ,the basket is placed at the base of the burner1 in order to obviate the shadow which would otherwise be cast by the apparatus2 and it is attached to the main body of the apparatus by platinum wires4 ,as to illuminating power1 the only particulars which have been made public refer to the first two models constructed2 one of which was said to develop a light equal to that from #f4bjh candles1 and the other to #i4gb candles per cubic foot of gas consumed4 ,illustration3 ,,fig4 #bh4--;,,clamond',s ,,improved ,,incandescent ,,burner4 ,sidenote3 ,clamond's new burner4 ,in a recently designed modification of the burner 7which is shown in the accompanying illustration7 ,m4 ,clamond dispenses with an artificial supply of air under pressure1 and endeavours to obtain similar results by other and simpler means4 ,to this end the position of the magnesia wick is reversed 7it being placed at the top of the apparatus72 the current of gas is allowed to draw in upon itself a quantity of air by a precisely similar arrangement to that adopted in the ,bunsen burner2 while an additional supply of air is drawn upon the flame by the accelerated draught produced by the aid of a glass chimney4 ,as in the more complicated and complete burner1 the air supply is heated by means of auxiliary burners in the interior of the apparatus4 ,it has been stated1 on the authority of ,m4 ,clamond1 that this modified burner develops1 from the gas consumed1 a duty of about #f candles per cubic foot2 being equal to the results yielded by the more complicated apparatus4 ,should this be borne out in practice1 ,m4 ,clamond will have achieved a noteworthy success4 ,it is1 however1 advisable to reserve expressing any definite opinion of its merits until further information is received1 or until the burner has been tried in this country4 ,,chapter ,,vii4 ,,conclusion4 ,the burners last mentioned may be said to mark the extent of the progress that has been made1 down to the present time1 in the construction of apparatus for developing light from coal gas2 and they remind me that ,i have arrived at the conclusion of my subject4 ,from the unpretending gas-jet described by ,accum--burning1 with wonder-provoking steadiness and constancy1 so long as the supply of gas continued--to the complicated apparatus of ,m4 ,clamond1 is a long stretch of invention2 embracing the labours of many distinct and original workers in the same field1 and including numerous variations in the details of burners that have not been touched upon in the foregoing remarks4 ,as was announced in the introduction1 ,i have dealt in this treatise only with the more important or the more successful of the modifications that have been made from time to time in the construction of the gas-burner4 ,in addition to the burners that have been referred to1 there have been invented many others1 which could not be adequately noticed without prolonging the treatise to an undue length4 ,some of these 7the fruit of much thought and careful experiment7 have obtained1 in the commercial success that has attended them1 no more than their merited reward2 others 7devoid of any real merit1 and in their construction disregarding the most elementary principles of economic combustion7 have been brought into somewhat extensive use by the misleading statements and false representations of their inventors1 and are only tolerated through the ignorance of the public2 while not a few of the latter class of burners have speedily found the oblivion which they richly deserved4 ,sufficient1 however1 has been said to show that many real improvements have been effected in the construction of gas-burners1 and to prove that1 with the apparatus now available1 a far higher duty may be obtained from the gas consumed than was possible only a few years ago4 ,but although the great advance that has been made in the construction of gas-burners is undoubted1 the benefits which ought to result therefrom have not been realized by the gas-consuming public2 nor are they likely to be to their full extent4 ,while the ingenious and effective inventions for utilizing the waste heat of combustion1 and for lighting by incandescence1 may1 and doubtless will1 in the course of a few years1 be far more extensively adopted than at present1 it is hardly to be expected that they will be generally employed4 ,two causes operate to preclude the latter result--namely1 their first cost1 and the care and attention demanded in their employment4 ,it seems tolerably certain that for a long time yet the great bulk of coal gas1 used for lighting purposes1 will be consumed through the simple flat-flame burners that have done so much hitherto for the furtherance of gas lighting4 ,fortunately so much has been done towards the perfection of this class of burners1 that1 for a very slight expenditure1 results may now be obtained far in advance of what could formerly be produced only by the most costly and delicate apparatus4 ,for ordinary situations and requirements1 the improved flat-flame burners produced by ,bray1 ,broenner1 and ,sugg1 when intelligently employed1 leave scarcely anything to be desired4 ,when intelligently employed1 ,i repeat1 and with cautious emphasis2 for the best of burners will be extravagant and ineffective if employed without due regard to the conditions for which it was made4 ,that which is most needed at the present day1 and which will best ensure the continued use of coal gas for the purposes of illumination1 is the more general diffusion amongst gas consumers of a knowledge of the principles of combustion1 and of the simple precautions to be taken and conditions to be fulfilled in the employment of gas-burners4 ,the apparatus that is available is both varied and effective2 what is wanted is the knowledge to use it aright4 ,by contributing to the freer dissemination of that knowledge1 purveyors of gas will confer no inconsiderable benefits upon their customers1 and1 at the same time1 will assuredly promote their own interests4