,transcriber's ,note ,subscripts are represented by bracketed numbers preceded by an underscore3 ,c#aj;,h#af4 ,,by ,,the ,,same ,,author4 ,arithmetic of ,electricity4 ,a ,complete and ,indispensable vade mecum for amateur1 student1 and electrical engineer4 ,fully ,illustrated4 ,price1 #a4jj4 ,home ,experiments in ,science4 #beb ,pages4 #if ,illustrations4 ,price1 #a4ej4 ,,rubber ,,hand ,,stamps ,,and ,,the ,manipulation of ,rubber ,a ,,practical ,,treatise ,,on ,,the ,,manufacture ,,of ,,india ,,rubber ,,hand ,,stamps1 ,,small ,,articles ,,of ,,india ,,rubber1 ,,the ,,hektograph1 ,,special ,,inks1 ,,cements1 ,,and ,,allied ,,subjects ,,by ,t4 ,o',,conor ,,sloane1 ,a4,m41 ,e4,m41 ,,ph4,d4 ,author of 8,home ,experiments in ,science10 8,arithmetic of ,electricity10 etc4 ,,fully ,,illustrated ,,new ,,york ,,norman ,w4 ,,henley ,,co4 #aej ,,nassau ,,street #ahia ,,copyright1 #ahij1 ,,by ,,norman ,w4 ,,henley ,,co4 ,,preface4 ,the present work hardly needs a preface4 ,the object is to present in the simplest form the subject of the manipulation of india rubber4 ,to mould and cure the mixed gum but few appliances are needed1 and these can be made at home4 ,the articles produced are of more than ordinary utility4 ,these two facts give value to the art and furnish a raison d'tre for this book4 ,if its instructions do not prove practical it will have missed its object4 ,for some reason the methods of moulding the material are not generally known4 ,experiment has taught many the futility of attempting to melt and cast it4 ,while thus intractable by the usual methods1 it is the most plastic of materials when properly treated4 ,its power of reproducing the finest details of a mould1 of entering all the intricacies and undercuttings of a design1 cause one to feel a peculiar pleasure in working with so responsive a material4 ,it is not saying too much to affirm that to some readers this book will disclose a long hidden secret4 ,to make it more generally useful it is written for such readers1 to meet the want of those knowing of the subject4 ,it was felt that in following this course1 and in treating the subject from its first steps1 including the simplest as well as most advanced methods1 the book would appeal to a larger body of readers4 ,the allied subjects to which some chapters are devoted will be acceptable to many readers4 ,the hektograph is given in several modifications4 ,a substitute for rubber stamps which stands the severe usage of the ,post ,office has very distinct merits1 and the manufacture is accordingly described in detail4 ,cements and inks embody many special formul4 ,in the last chapter interesting and practical notes will be found4 ,for the use of certain cuts we are under obligations to the ,buffalo ,dental ,manufacturing ,co41 ,messrs4 ,e4 ,f4 ,n4 ,spon ,co41 and to ,mr4 ,l4 ,spangenberg4 ,,contents4 ,,page ,,chapter ,i4 ,,the ,,sources ,,of ,,india ,,rubber ,,and ,,its ,,history4 ,the ,trees--,the ,sap--,caoutchouc--,early ,uses by the ,indians--,first knowledge of it in ,europe--,goodyear1 ,day1 and ,mackintosh #i ,,chapter ,,ii4 ,,the ,,natural ,,history ,,and ,,collection ,,of ,,india ,,rubber4 ,african1 ,east ,indian1 ,central and ,south ,american ,gums--,different ,methods of ,collection and ,coagulation #ae ,,chapter ,,iii4 ,,properties ,,of ,,unvulcanized ,,and ,,vulcanized ,,india ,,rubber4 ,properties of ,unvulcanized ,rubber2 its ,cohesion and importance of this property--,analysis of ,sap and ,caoutchouc--,effects of ,heat and ,cold--,distillation ,products--,vulcanized ,rubber1 and its ,properties #bd ,,chapter ,,iv4 ,,the ,,manufacture ,,of ,,masticated1 ,,mixed ,,sheet ,,and ,,vulcanized ,,india ,,rubber4 ,treatment by the ,manufacturer--,washing and ,sheeting--,masticating--,making ,sheeting and ,threads--,mixing--,curing--,coated ,tissues #ce ,,chapter ,v4 ,,india ,,rubber ,,stamp ,,making4 ,mixed ,sheet--,outlines of ,moulding--,home-,made ,vulcanizing ,press--,further ,simplifications of ,same--,securing ,accurate ,parallelism of ,platen and ,bed--,distance ,pieces--,wood vs4 ,iron as ,material for ,press--,use of ,springs on the ,home-,made ,press--,metal ,flask ,clamps--,large ,gas-,heated ,vulcanizing ,press--,preparing ,type ,model--,the ,matrix--,plaster of ,paris and ,dental ,plaster as ,substances for ,matrices--,dextrine and ,gum ,arabic ,solutions for ,mixing ,matrix--,how ,matrix is made--,shellac ,solution for ,matrix--,matrix ,press and ,spring-,chase--,how to retard the ,setting of ,plaster of ,paris--,oxychloride of ,zinc ,matrices--,talc ,powder--,moulding and ,curing the ,stamp--,kerosene ,heating ,stove--,manipulation of ,press--,degree of ,heat--,simple ,test of ,curing--,time ,required--,combined ,matrix ,making and ,vulcanizing ,apparatus--,chamber ,vulcanizers--,object of ,steam in ,vulcanizers--,temperature ,corresponding to ,different ,steam ,pressures--,jacketed ,vulcanizers--,gas ,regulator--,flower ,pot ,vulcanizer--,fish ,kettle ,vulcanizer--,making ,stamps without any ,apparatus ,whatever--,notes on ,type1 ,quadrats and ,spaces--,autograph ,stamps #dg ,,chapter ,,vi4 ,,india ,,rubber ,,type ,,making4 ,movable ,type ,making--,simple ,flask and ,matrix--,precautions as to ,quantity of ,rubber--,moulding--,curing--,cutting ,type ,apart--,special ,steel ,moulds--,wooden ,bodied ,type #gc ,,chapter ,,vii4 ,,the ,,making ,,of ,,stamps ,,and ,,type ,,from ,,vulcanized ,,india ,,rubber4 ,ready ,vulcanized ,gum as ,material for ,stamps--,simplicity of the ,process of ,using ,it--,advantages and ,disadvantages--,availability for ,type #gg ,,chapter ,,viii4 ,,various ,,type ,,matrices ,,for ,,rubber ,,stamps ,,and ,,types4 ,electrotype ,matrices--,papier ,mach--,flong ,paste--,flong ,matrices--,beating into ,model--,drying and ,baking--,struck-up ,matrices--,chalk ,plates #hj ,,chapter ,,ix4 ,,the ,,making ,,of ,,various ,,small ,,articles ,,of ,,india ,,rubber4 ,suction ,discs--,pencil ,tips--,cane and ,chair ,leg ,tips--,corks--,mats--,cord and ,tubes--,bulbs and ,hollow ,toys #he ,,chapter ,x4 ,,the ,,manipulation ,,of ,,sheet ,,rubber ,,goods4 ,sheet ,rubber ,articles--,toy ,balloons--,uses of ,sheet ,rubber in the ,laboratory #id ,,chapter ,,xi4 ,,various ,,vulcanizing ,,and ,,curing ,,processes4 ,liquid ,curing ,baths--,sulphur ,bath--,haloids and ,nitric ,acid as ,vulcanizers--,alkaline ,sulphides--,sulphur ,absorption ,process--,parke's ,process #ig ,,chapter ,,xii4 ,,the ,,solution ,,of ,,india ,,rubber4 ,mastication with ,solvent--,peculiarities of the ,process--,different ,solvents and their ,properties--,paraffin--,vulcanized ,rubber ,solution--,aqueous ,solution #ajc ,,chapter ,,xiii4 ,,ebonite1 ,,vulcanite ,,and ,,gutta-,,percha4 ,ebonite and ,vulcanite--,manufacture--,manipulation- -,gutta-,percha and its ,manipulation #ajh ,,chapter ,,xiv4 ,,glue ,,or ,,composition ,,stamps4 ,substitute for ,rubber ,stamps--,the ,united ,states ,government ,formula--,models and ,moulds--,dating--,handles #aac ,,chapter ,,xv4 ,,the ,,hektograph4 ,how ,made--,the ,french ,government ,formula--,hektograph ,sheets #aba ,,chapter ,,xvi4 ,,cements4 ,marine ,glue1 and other special ,cements #abe ,,chapter ,,xvii4 ,,inks4 ,hektograph1 ,stencil and ,marking ,inks--,white and ,metallic ,inks #abi ,,chapter ,,xviii4 ,,miscellaneous4 ,preservation and ,renovation of ,india ,rubber--,burned ,rubber for ,artists--,india ,rubber ,substitutes--,general ,notes of ,interest #acd ,,rubber ,,hand ,,stamp ,,making ,,and ,,the ,,manipulation ,,of ,,rubber4 ,,chapter ,i4 ,,the ,,sources ,,of ,,india ,,rubber ,,and ,,its ,,history4 ,india rubber or caoutchouc is a very peculiar product1 which is found in and extracted from the juice of certain trees and shrubs4 ,these are quite numerous and are referred for the most part to the following families3 ,euphorbiaced1 ,urticaced1 ,artocarped1 ,asclepiadaced1 and ,cinchonaced4 ,it is evident that a considerable number of trees are utilized in commerce for its production1 and it is certain that it exists1 quite widely distributed1 in many cases as a constituent of the juice of plants not recognized as containing it4 ,when an india rubber tree is tapped1 which is effected by making incisions in the bark1 the sap of the tree exudes4 ,it is a milky substance and is collected in various ways2 it may be in vessels of clay1 in shells1 or in other receptacles by the india rubber hunters4 ,if this substance is examined it is found to be of very remarkable and characteristic constitution1 resembling in its physical features ordinary milk4 ,it is composed of from fifty to ninety per cent4 of water1 in which is suspended in microscopic globules1 like the cream in milk1 the desired caoutchouc or india rubber4 ,if the juice is left to stand in vessels1 like milk in a creamery1 the globules rise to the surface1 and a cream of india rubber can be skimmed off from the surface4 ,if the juice is evaporated over a fire1 the water escapes and the india rubber remains4 ,by dipping an article repeatedly in the juice and drying it1 a thick or thin coating of india rubber can be developed4 ,before the modern methods for the manipulation of the gum had been developed1 and before the invention of vulcanization1 this method was adopted for the manufacture of shoes4 ,the original 8india rubbers0 for protection of the feet in wet weather were made in this manner4 ,a clay last was used1 upon which the india rubber was deposited as described4 ,the clay last was then broken out and removed4 ,great quantities of overshoes were thus made in ,south ,america1 and many were exported to ,europe4 ,when caoutchouc has once been removed from this watery emulsion1 which for all practical purposes is a solution1 it cannot be restored to the former state of liquidity2 it remains solid4 ,it will absorb a considerable quantity of water1 but will not enter again into the quasi solution or combination4 ,this property of permanent coagulation1 which interferes to a degree with its easy manipulation1 was early discovered4 ,in the last century quantities of the natural milk were exported to ,europe to be used in what may be termed the natural process of manufacture1 because once solidified it could not be redissolved1 and because the manufacturers of those days had not the present methods of dealing with the apparently intractable gum4 ,the natives of ,south ,america before the advent of ,europeans1 were familiar with the treatment of the juice by evaporation just described and used to make bottles1 shoes and syringes of it for their own use4 ,the name ,siphonia applied to several species of rubber tree1 and seringa 7caoutchouc7 and seringari 7caoutchouc gatherer7 in ,spanish recall the old ,indian syringes and tubes4 ,the gum is now collected for export in many parts of the world4 ,south and ,central ,america are1 as they have always been1 the greatest producers4 ,some is collected in ,africa1 ,java and ,india4 ,the best comes from ,para4 ,however carefully treated a great difference is found in the product from different countries4 ,the ,brazilian india rubber1 known as ,para1 from the port of shipment1 ranks as the best in the market4 ,its history as far as recorded1 does not go back of the last century4 ,le ,condamine1 who explored the ,amazon ,river1 sent from ,south ,america in #agcf to the ,institute de ,france1 in ,paris1 the first sample of india rubber ever seen in ,europe4 ,he accompanied the sample with a communication4 ,he said that the ,indians of that country used the gum in making several domestic objects of utility1 such as vessels1 bottles1 boots1 waterproof clothing1 etc4 ,he stated that it was attacked and to a certain extent dissolved by warm nut oil4 ,in #agea and #agfh other samples were received through ,,mm4 ,fresnau and ,maequer1 who sent them to the ,academy of ,sciences1 ,paris1 from ,cayenne in ,guiana4 ,although from this period numerous experiments were tried with the new substance little of importance was done with it for many years4 ,its first use was to rub out pencil marks1 whence it derived its name of 8india rubber40 ,as late as #ahbj this continued to be its principal use4 ,an interesting reminiscence of its early history is given by ,joseph ,priestley1 the great ,english chemist of the last century1 celebrated as the discoverer of oxygen4 ,in #aggj he mentioned the use of the gum for erasing pencil marks1 and speaks of its cost being three shillings1 about seventy cents1 for 8a cubical piece of about half an inch40 ,as we have seen1 its solubility was early studied4 ,in #agfa ,hrissant added turpentine1 ether and 8huile de ,dippel0 to the list of solvents4 ,in #agic its solubility was utilized in ,france by ,besson1 who made waterproof cloth4 ,in #agig ,johnson introduced for the same manufacture a solution in mixed turpentine and alcohol4 ,the year #ahbj is the beginning of the period of its modern use on a more extended scale4 ,nadier developed the methods of cutting it into sheets and threads and of weaving the latter4 ,mackintosh in #ahbc began the manufacture of waterproof cloth1 using the solution of the gum in coal tar naptha1 which was caused to deposit by evaporation a layer of the gum upon a piece of cloth which was covered by a second one4 ,this protected the wearer from the gummy and sticky coating of raw india rubber4 ,at the best the original ,mackintoshes must have been very disagreeable articles for wear4 ,in #ahbe india rubber shoes of raw india rubber were imported from ,south ,america and formed for a while an important article of commerce4 ,in #ahci ,charles ,goodyear1 of ,massachusetts1 invented the art of vulcanizing1 or combining india rubber with sulphur4 ,it was patented on ,june #ae1 #ahdd1 and covers only the manufacture of soft rubber4 ,vulcanite or hard rubber 7whalebone rubber7 is disputed as to its origin1 its invention being assigned by some to ,nelson ,goodyear and by others to ,austin ,g4 ,day1 of ,connecticut4 ,goodyear however succeeded in obtaining a patent on ,may #f1 #ahea4 ,day obtained a patent on ,august #aj1 #aheh4 ,vulcanization is the most important invention ever made in connection with india rubber and may fairly rank as one of the greatest discoveries of the present century4 ,it is claimed by the ,english1 an inventor named ,handcock being cited as the rival of ,charles ,goodyear4 ,the latter inventor had as an associate ,nathaniel ,hayward1 who is probably entitled to some of the credit4 ,by vulcanization india rubber loses susceptibility to heat and cold1 becomes non-adherent1 and insoluble in almost all substances4 ,it is converted from a comparatively useless substance into one of wide applicability4 ,the subject of india rubber is so interesting in its theoretical as well as practical bearings that it seems impossible that those who are workers in it should not feel an interest in its natural history4 ,for such readers the chapter on the natural history and collection of india rubber has been written4 ,as it is a product of widely separated lands on both hemispheres1 and as it is yielded by an immense number of plants1 it is impossible in the limits of a chapter to give a full outline of its natural history4 ,the chapter in question is1 therefore1 with this apology1 inserted where it belongs1 near the beginning of the book4 ,those who are entirely practical may pass it over4 ,there is no doubt that the few minutes necessary for its perusal will be bestowed upon it by some4 ,,chapter ,,ii4 ,,the ,,natural ,,history ,,and ,,collection ,,of ,,india ,,rubber4 ,african india rubber is mostly exported from the west coast4 ,the belt of country producing it extends nearly across the continent4 ,those who are familiar with the india rubber plants of our conservatories are apt to think of the gum as the product of trees1 but in ,africa it is largely yielded by climbing plants of very numerous varieties1 belonging generally to the ,landolphia species4 ,it is collected by the natives by careless or desultory methods1 probably less advanced than the ways followed by the ,south ,americans4 ,possibly its marked inferiority may be partly attributed to this4 ,it is also supposed by many that1 were the gathering restricted to the vine producing the best gum1 better results would follow4 ,as it is now all gums are mixed indiscriminately4 ,african gum is of very inferior quality4 ,the ,african india rubber vines grow often in dark moist ravines1 where no valuable product other than themselves could be cultivated4 ,they are entirely wild4 ,the vines when cut exude an abundance of sap1 which differs from the ,south ,american product in its quickness of coagulation4 ,as it escapes from the wound it at once solidifies and prevents the further escape of juice4 ,the negroes are said to employ the following highly original method of collecting it4 ,they make long gashes in the bark4 ,as fast as the milky juice comes out they wipe it off with their fingers and wipe these in turn on their arms1 shoulders1 and body4 ,in this way they form a thick covering of inspissated juice or caoutchouc over the upper part of their body4 ,this from time to time is removed by peeling4 ,it is then said to be cut up and boiled in water4 ,this is one account4 ,according to others the natives remove a large piece of bark1 so that the juice runs out and is collected in holes in the earth or on leaves4 ,wooden vessels are said to be used elsewhere4 ,sometimes the juice is said to be collected upon the arms1 the dried caoutchouc coming off in the shape of tubes4 ,a clew to the inferiority of ,african india rubber is afforded by the statement that too deep a cut liberates a gum which deteriorates the regular product if it mixes with it4 ,the drying of the gum is thought to have much to do with its quality and it is highly probable that this affects the ,african product4 ,some samples seem to be partly decomposed they are so highly offensive in odor4 ,the ,south ,american rubber is often dried in thin layers1 one over the other1 by a smoky fire1 which may have an antiseptic effect upon the newly coagulated caoutchouc4 ,no such process as far as known is used in ,africa4 ,the ,african india rubber appears under different names in commerce4 ,from the ,congo region lumps of no particular shape called 8knuckles02 from ,sierra ,leone smooth lumps1 8negro-heads10 and 8balls0 made up of small scrap2 from the ,portuguese ports 8thimbles10 8nuts10 and 8negro-heads20 from the gaboon 8tongues20 and from ,liberia 8balls0 are received4 ,it is all characterized by great adhesiveness and low elasticity4 ,from ,assam1 ,java1 ,penang1 and ,rangoon there is considerable gum exported4 ,it is supposed to be the product of trees of the ficus species1 in all these places1 as it is known to be in ,java and ,assam4 ,in the latter place rigid restrictions are imposed as far as possible upon the gathering4 ,in the case of wild trees scattered through the forest the carrying out of these restrictions is not practicable4 ,the trees are cut with knives in long incisions through the bark and the juice is collected in holes dug in the ground1 or often in leaves wrapped up into a conical form1 somewhat as grocers form their wrapping paper into cornucopia shape for holding sugar1 etc4 ,it has seemed reasonably certain that the india rubber producing plants might be cultivated with profit1 and it is as certainly to be feared that without such cultivation they will become extinct4 ,efforts have been made in the direction of raising them artificially but without much success4 ,in ,assam numerous experiments have been made to propagate the india rubber bearing ficus tree4 ,a good instance of the ill effects of carelessness in the original gathering of the crop is afforded by the ,bornese collectors4 ,the source of ,borneo india rubber is a variety of creepers4 ,these are cut down and divided into short sections from a few inches to a yard in length4 ,the sap oozes out from the ends4 ,to accelerate its escape the pieces are sometimes heated at one end4 ,it is coagulated by salt water4 ,sometimes a salt called nipa salt1 obtained by burning a certain plant 7nipa fruticans71 is used for the purpose4 ,in either case it is coagulated into rough balls and masses4 ,these masses are heavily charged with the salt water1 often containing as much as fifty per cent41 and rarely much less than twenty per cent4 ,illustration3 ,,tree ,,felled ,,for ,,collection ,,of ,,india ,,rubber4 ,central ,america and ,panama are great producers of the gum4 ,in ,panama the custom of felling the trees is often adopted4 ,in this case grooves are cut around the prostrate trunk1 and under each groove as the trunk lies on the ground a vessel is placed to collect the sap4 ,its coagulation is often effected by leaving it for a couple of weeks standing at rest in a hole1 excavated on the surface of the ground1 and covered over with leaves4 ,the caoutchouc separates under these conditions4 ,a quicker method1 but one yielding an inferior product1 is obtained by adding to the fresh juice some bruised leaves of a plant 7ipoma bona nox7 which acts something like acid upon milk1 in separating the desired solid matter or caoutchouc4 ,a jelly like accretion saturated with blackish water is thus obtained4 ,by working it together a blackish liquid is caused to escape1 and comparatively pure gum is gradually obtained4 ,as much as one hundred pounds of india rubber may be obtained from a single tree where this destructive system is employed4 ,further north1 where a better counsel has prevailed1 the trees are only tapped1 and the india rubber hunter is satisfied if from a tree eighteen inches in diameter he obtains twenty gallons of sap1 giving fifty pounds of gum4 ,even where tapping is done the tree is often destroyed by carelessness or ignorance4 ,two systems are followed in ,nicaragua4 ,the operator ascends by a ladder if he has one1 or in any case climbs as high as he well can and begins to make a long incision4 ,sometimes he carries one long straight cut clear down to the ground4 ,this is made the starting point for a number of side cuts1 short1 and running diagonally into it4 ,this is also one of the ,brazilian methods4 ,the ,nicaraguan sometimes also makes two spiral incisions1 one right-handed and the other left-handed1 crossing each other as they descend so as to divide the surface of the tree into roughly outlined diamonds4 ,in either case the juice flows down to an iron spout1 placed at the bottom of the tree1 which spout leads to an iron pail4 ,the milk is gathered and passed through a sieve1 and coagulated in barrels by the ipoma plant as before mentioned4 ,this gives three grades of rubber4 ,the bulk is obtained from the barrels and is called often mros2 the small lump which forms in the spout is rolled into a ball and called cabezza2 the dried strips pulled out of the cuts is of very good quality and is called bola or burucha4 ,from ,brazil is exported the famous ,para india rubber4 ,this is of very high quality1 and is greatly esteemed by all manufacturers4 ,no process can make a poor gum give a really good product4 ,the system of gathering it varies4 ,sometimes the tree is cut into by gashes from an axe1 such gashes extending in a row all around the trunk4 ,under each gash a small clay cup is luted fast with some fresh mixed clay4 ,these collect from a tablespoonful of juice upward1 which is collected1 and the cups are removed on the same day4 ,the next day a second row of cuts is made below the others1 and the same process is repeated4 ,this is continued until from a point as high as a man can reach1 down to the ground the tree is full of cuts4 ,sometimes a gutter of clay is found partly around the trunk with gashes above it4 ,in other cases a vine is secured around the tree and a collecting gutter is worked with it for a basis4 ,illustration3 ,,tree ,,tapped ,,for ,,india ,,rubber4 ,the juice is coagulated in a smoky fire4 ,a bottomless jar is placed over the fire and some palm nuts are mixed with the fuel4 ,the mould1 which is often a canoe paddle1 is smeared with clay to prevent adhesion and is then heated4 ,a cup of juice is poured over it1 and after the excess has dropped off it is moved about rapidly over the smoke and hot air which ascends from the mouth of the jar4 ,this series of operations is repeated until the coating is quite thick2 it may be as much as five inches4 ,after solidifying over night it is cut open and the paddle or mould is removed4 ,after a few days drying it is sent to market4 ,with all the heating1 during which it sweats profusely1 it still retains fifteen per cent4 of water4 ,illustration3 ,,indian ,,drying ,,and ,,smoking ,,india ,,rubber4 ,india rubber sap may be coagulated by an aqueous solution of alum4 ,the process has been tried in ,brazil1 and is used to a considerable extent in ,pernambuco4 ,it was proposed by an investigator named ,strauss1 and the process is still called by his name4 ,one objection is that it gives a very wet product1 and apparently one of inferior value to the smoked gum4 ,the feeling that india rubber suffers in the gathering has been so much felt that it has been recently suggested that if possible the uncoagulated juice should be exported to ,europe there to be worked up from the beginning4 ,,chapter ,,iii4 ,,properties ,,of ,,unvulcanized ,,and ,,vulcanized ,,india ,,rubber4 ,there are two broad divisions to which all varieties of india rubber can be assigned--unvulcanized and vulcanized rubber4 ,speaking with a certain amount of license it may be said that more properties characterize the former than the latter4 ,the vulcanized article is very slightly affected by ordinary changes of temperature1 cannot to any considerable extent be changed by heat short of absolute destruction or decomposition1 cannot be united or moulded except in simple forms1 is highly elastic1 and is insoluble in almost every solvent for ordinary caoutchouc4 ,unvulcanized caoutchouc possesses very interesting and peculiar properties4 ,the first part of the present chapter is devoted to this substance4 ,those who have never seen the crude gum as imported are familiar with the article almost pure in the form of sheet rubber and black rubber articles generally4 ,these are of nearly pure caoutchouc1 though recently the tendency is to vulcanize them to a considerable degree4 ,a piece of pure gum containing no combined sulphur1 iodine1 or other vulcanizing constituent will be found to exhibit a very striking peculiarity4 ,two freshly cut surfaces when placed in contact will adhere4 ,this is not in consequence of any viscous or sticky coating4 ,when india rubber is cut the surface is perfectly dry and non-adherent except to itself4 ,the writer once had this property of adhesion brought strongly to his attention4 ,in some analytical investigations of coal gas he had proposed to use finely divided india rubber as an absorbent of sulphur4 ,this constituent it absorbs from gas1 and it seemed that a basis for a quantitative determination of sulphur might be found in such property4 ,accordingly some raw india rubber was procured and with some trouble was cut up into little pieces which were put into a bottle4 ,a day or two afterwards the pieces united wherever they were in contact1 and an irregular cavernous lump was the result4 ,this involved no melting or softening or change of shape4 ,each little piece was there intact and distinct but firmly attached to its neighbors4 ,the analogy of this action is seen in lead4 ,two fresh surfaces brought together1 preferably with a twisting or wrenching pressure1 adhere quite firmly4 ,the adherence of india rubber and of lead each to itself is often exhibited by physical lecturers as an illustration of cohesion4 ,the cohesion of india rubber is however far more perfect than that of lead1 probably because of its comparatively great resistance to oxidation1 and because1 owing to its elasticity larger areas can be brought in contact4 ,comparatively great though this resistance to oxidation is1 oxygen1 especially in the allotropic modification known as ozone1 may act quite powerfully on the gum4 ,sunlight also can affect it injuriously4 ,a more familiar illustration of the uniting of two pieces of the same material is seen in the welding of iron4 ,the blacksmith heats two pieces of iron until they are nearly white hot and are pasty in consistency4 ,on placing them in contact and hammering to force them together they unite so firmly as to be practically one4 ,it is necessary that the surfaces of clean metal should be brought together4 ,if the pressure induced by the hammering is insufficient to bring this about1 a flux is added which dissolves the oxide and causes the metal to come in contact with metal and to weld4 ,the analogy with india rubber in its cohesive action is evident4 ,surfaces long exposed or which are dusty do not cohere4 ,the relegation of ice is similar in effect4 ,the cohesion of india rubber is important and should be thoroughly appreciated4 ,it is not saying too much to assert that the entire treatment of the raw gum depends upon this interesting property4 ,the great lumps of gum are torn to pieces and washed free from gravel and dirt without going to powder1 because owing to their elasticity they yield and as fast as torn apart the pieces tend to reunite4 ,again india rubber is mixed with pigments and vulcanizing reagents by a method practically one of grinding or masticating1 but the material while it changes its shape1 and by the admixture of the various ingredients becomes less strong or easier torn1 still remains intact1 as it welds together or coheres as fast as disintegrated4 ,as regards its chemical constitution the sap of a ,para rubber tree has been analyzed with the following general results3 7,faraday74 ,caoutchouc #cj4gj ,albuminous1 extractive1 and saline matter1 etc4 #ab4ic ,water #ef4cg ------ #ajj4jj ,its specific gravity is #a4jab4 ,caoutchouc itself or raw india rubber is a mixture of several hydrocarbons of the following composition in general3 ,carbon #hg4e ,hydrogen #ab4e ----- #ajj4j ,its specific gravity is from 4#iab to 4#idb4 ,the hydrocarbons composing it are isomeric or polymeric with turpentine4 ,this fact brings it well within the range of familiar vegetable products4 ,as will be seen the products of its distillation fall among the same polymers and isomers4 ,when pure it is nearly colorless1 the dark color being due to impurities4 ,in thin sheets it is almost or quite transparent4 ,it burns readily1 and with a very luminous1 smoky flame1 as might have been anticipated from its composition4 ,the action of heat and cold on it is dependent on the degree of the temperature4 ,at ordinary temperature it is elastic and firm4 ,it can be stretched and will return almost to its original size when released from tension4 ,yet the return to its shape is so liable to be incomplete1 especially after long sustained stretching1 that pure unvulcanized india rubber is considered imperfectly elastic4 ,any elasticity it possesses is principally elasticity of shape as distinguished from elasticity of volume4 ,in other words when pressed or stretched it may change shape to a great extent but hardly change its volume at all4 ,a cube of #b inches under a weight of #bjj tons lost #a-aj of its volume only4 ,this is largely due to the fact that it represents an approximately solid body1 or one destitute of considerable physical pores4 ,solids and liquids are very slightly compressible4 ,whatever degree of compressibility caoutchouc possesses is due principally to its minute pores4 ,if the temperature is reduced to the freezing point of water a piece of raw india rubber becomes rigid and stiff4 ,on application of heat it returns to its former pliable condition4 ,the same return to flexibility may be brought about by stretching it mechanically4 ,this may be rather a fallacy4 ,stretching india rubber warms it1 so that in this mechanically imparted rise of temperature we may find at least a probable cause of the softening4 ,if the temperature is raised several effects are produced1 according to circumstances4 ,a piece which has been stretched and held stretched1 has its tension increased by a degree of heat considerably less than that of boiling water4 ,some offer the theory that it contains air enclosed in its pores which1 expanding1 produces this effect4 ,as the boiling point is reached the material softens and becomes somewhat plastic1 so that it can be moulded into shape to a considerable extent and stretched to threads of great fineness4 ,its elasticity also disappears as the heat is maintained4 ,these effects increase in extent up to a heat of #bdh ,f4 7#abj ,c474 ,the return to its original state is not immediate however4 ,some time is required before the reduction of temperature will have full effect4 ,if now a still higher degree of heat is applied1 #cib ,f4 7#bjj ,c47 the india rubber softens to a viscous body1 or melts4 ,from this state it cannot be restored4 ,it remains permanently 8burned0 or melted whatever is done to it4 ,some attempt at hardening may be made by the use of vulcanizing chemicals1 but the result will be very imperfect4 ,a further increase of heat brings about a destructive distillation4 ,india rubber treated in a retort to a heat exceeding #djj ,f4 7#bjd ,c47 evolves volatile hydrocarbons of oily consistency1 and it distills almost completely1 a small residue of gummy matter or of coke if the final heat has been pushed far enough being left4 ,the distillate is called caoutchoucin4 ,according to ,mr4 ,greville ,williams it consists of two polymeric hydrocarbons3 one1 caoutchin ,c#aj;,h#af1 boiling point #cdj ,f4 7#aga ,c472 the other1 isoprene ,c#e;,h#h 7in formula equal to one-half of caoutchin71 boiling point #ii ,f4 7#cg ,c474 ,the mixture has a strong naptha-like odor and has won considerable reputation as being the best solvent for india rubber4 ,how far it deserves its reputation is a matter open to discussion4 ,the solution of india rubber like its fusion is a vexed point4 ,there is little question that it can be dissolved by proper treatment4 ,usually naptha1 carbon disulphide or benzole are used as solvents1 the choice being guided by motives of cheapness and efficiency4 ,it is worthy of remark that the formula given for caoutchoucin is the same as that of the principal constituent of oil of turpentine1 and that the latter is often recommended as a solvent4 ,turpentine is slightly more volatile than caoutchoucin1 its boiling point being #cbb ,f4 7#afa ,c47 ,other hydrocarbons have been recognized in the distillate by ,bouchardat1 ,himly and ,g4 ,williams1 varying in boiling point from #cb ,f4 7#j ,c47 to #eii ,f4 7#cae ,c471 and in specific gravity from #j4fcj to #j4iba4 ,although it has been spoken of as approximately solid it does possess microscopic pores1 to which its limited amount of elasticity of volume is mostly due4 ,thus it is found to absorb water1 in which it is quite insoluble4 ,as it does this it acts like a dry sponge and increases in volume a little1 owing to dilation of these minute pores4 ,the water absorbed may be as much as #ah4g to #bf4d per cent4 with an increase of volume of the gum of #ae_/ajjj to #af_/ajjj4 ,when it has once absorbed water it is very hard to get rid of it4 ,although the minute surface orifices communicate with the entire system of capillary vessels and pores1 the surface pores on drying contract and seal up the absorbed water within the mass4 ,this is a clew to the impracticability of the gatherer shipping dry rubber1 and to the great difficulty the manufacturer experiences in drying his washed and sheeted stock before working it up by masticating or mixing and curing4 ,by proper manipulation caoutchouc may be made inelastic4 ,this can be done by the freezing process or by keeping it stretched for two or three weeks4 ,in this way threads can be made to extend and to remain extended to seven or eight times their original length4 ,they can then be woven into a fabric4 ,on gentle heating their original elasticity reappears and they contract4 ,in this way fluted braids can be made which will have a high capacity for stretching4 ,the solution of caoutchouc is difficult often to bring about4 ,we have seen that in water it swells a little without dissolving4 ,in benzole it does the same1 but swells to a greater extent1 to #abe times its original volume or even more4 ,some authorities 7,watts7 go so far as to assert that no solvent completely dissolves it4 ,acting on it repeatedly with benzole or other solvent and taking care not to break up the swelled mass1 from #di to #fj per cent4 of soluble matter can be extracted4 ,on evaporation this is deposited as a ductile adherent film4 ,the swelled up residue which remains undissolved is assumed to be the constituent giving strength and elasticity1 and is only sparingly soluble4 ,if the gum is masticated or kneaded at the temperature of boiling water a change occurs not well understood1 by which its solubility is greatly increased4 ,as solvents many liquids have been named4 ,oil of turpentine1 caoutchoucin1 coal-tar1 naptha1 benzole1 petroleum-naptha1 coal-tar-naptha1 anhydrous ether1 many essential oils1 chloroform1 bisulphide of carbon1 pure1 or mixed with seven or eight per cent4 of alcohol1 are among the solvents recommended4 ,a mixture of fifty parts of benzole and seventy parts of rectified turpentine has been given as a solvent for twenty-six parts of the gum4 ,mastication before or after immersion in the solvent is to be advised4 ,more will be said on this subject in a succeeding chapter4 ,vulcanized india rubber is unaffected by changes of temperature within ordinary range4 ,it softens a little on heating4 ,even hard vulcanite when heated can be bent and will retain the bend on cooling4 ,it is exceedingly elastic with elasticity of shape but far less compressible as regards absolute change of volume than the raw gum4 ,it melts at #cib ,f4 7#bjj ,c47 ,it cannot be made to cohere1 and no cement has yet been discovered that will satisfactorily unite two surfaces4 ,it is unaffected by light1 by ordinary acids and rubber solvents4 ,in contact with the latter solvents it swells sometimes to nine times its original volume1 but on heating returns to its original volume and shape4 ,of water it will absorb no more than four per cent4 and often much less4 ,if it is maintained at a high temperature #bff to #cjb ,f4 7#acj to #aej ,c47 for a long time it gradually loses its flexibility1 especially if in contact with metals4 ,often the escape of sulphuretted hydrogen may be observed under these conditions4 ,a small admixture of coal tar operates to prevent this action4 ,its composition and specific gravity vary widely as the most varied mixtures are added by the manufacturer4 ,its relation of carbon to hydrogen is unaffected by the mixtures added4 ,while it may contain twenty per cent4 or more of sulphur it is believed that but a very small quantity is combined with it1 although the excess of sulphur or some equivalent1 such as sulphide of antimony is essential to vulcanization4 ,the combined sulphur is from one to two per cent4 ,some or all of the excess of sulphur is mechanically retained1 and as the rubber in ordinary use is worked about1 keeps escaping and forms a whitish dust upon the surface4 ,by treatment with alkali some of the excess of sulphur can be removed when the rubber acquires the power of absorbing a little more water1 up to six and four-tenths per cent4 ,boiling oil of turpentine is given as its solvent4 ,,chapter ,,iv4 ,,the ,,manufacture ,,of ,,masticated1 ,,mixed ,,sheet1 ,,and ,,vulcanized ,,india ,,rubber4 ,the manufacture of india rubber relates to the production of two principal products4 ,one is masticated unvulcanized sheet and thread rubber2 the other is unmasticated mixed and cured rubber1 otherwise vulcanized rubber4 ,for the purposes of the rubber-stamp maker an intermediate product is required1 namely1 unmasticated mixed sheet which is uncured4 ,this is really incompletely vulcanized india rubber4 ,it will be evident from the description to come that it is not advisable for any one without considerable apparatus to attempt to clean and to wash 78to sheet071 to masticate1 or to mix india rubber4 ,these operations are best accomplished in the factories4 ,the partially vulcanized 78mixed sheet07 or the pure masticated article are regular articles of commerce4 ,yet a full insight into the manipulation of india rubber can only be obtained by understanding its treatment from the gum up to the two separate lines of products we have indicated4 ,a third type of product is coated tissue1 such as ,mackintosh4 ,this really is a sequence of one of the other two processes and a few words will be said of it in concluding the chapter4 ,as the caoutchouc is received by the manufacturer it appears an utterly intractable mass4 ,it occurs in lumps of every size1 varying in color and odor1 and very tough but elastic4 ,in virtue however of the properties already described1 its power of cohering when cut1 and its softening when heated1 it becomes amenable to treatment4 ,it is to some extent received in such assorted condition as to secure even grades1 and then each grade may be washed by itself4 ,it is thrown into water which is in many cases kept at the boiling point by steam-heat and left there for some hours4 ,it absorbs some water and also softens4 ,some gum is so soft that it will not stand hot water4 ,for such the water is kept cold4 ,the purer gum floats2 such pieces as have stones1 dirt1 iron1 etc4 in them1 perhaps placed there purposely from fraudulent motives1 sink and can be picked out for separate treatment4 ,the lumps are next cut up4 ,a revolving circular knife driven by power is often used1 and sometimes an ordinary knife is adopted4 ,at this part of the operation there is frequently need for sorting1 as the grades received may have inferior pieces mixed with the good4 ,the cutting is mainly to secure good grading1 and to remove concealed impurities4 ,the gum then goes to the washing rollers1 called the washer and sheeter4 7,see cut1 p4 #cg47 ,illustration3 ,,washer ,,and ,,sheeter4 ,these are heavy corrugated rolls made very short1 #i-ah inches in length1 to prevent springing4 ,they are grooved or corrugated and have a screw adjustment for regulating their distance apart4 ,they are geared together so as to work in corresponding directions1 like a clothes wringer or a rolling mill of any kind4 ,the pieces of gum are fed into the rolls and are drawn between and through them4 ,the friction tends to heat the gum4 ,to prevent this and also to effect the washing1 a supply of water1 either hot or cold1 is kept playing upon the mass4 ,this dissolves out all soluble matter and washes away mechanically the chips1 dirt1 etc4 which may be present4 ,the whole operation is one of main force4 ,the caoutchouc is torn and distended and delivered as a rough perforated sheet4 ,it is passed repeatedly through the machine1 the rollers being gradually brought closer together1 or else different sets of rolls are used1 set to different degrees of fineness4 ,the wash water passes through a screen which catches any small detached fragments of gum4 ,other types of machines have been introduced2 the above is a representative form4 ,the rough sheets must now be perfectly dried1 as water impairs the final product4 ,this is done in drying rooms by steam heat1 generally1 at a temperature of about #ij ,f4 7#cb ,c47 ,the windows1 if there are any1 are painted to exclude sunlight1 which operates to deteriorate raw gum4 ,when absolutely dry the caoutchouc is removed and stacked away for use4 ,illustration3 ,,masticating ,,machine4 ,to prepare pure gum for the manufacture of sheet rubber and as a starting point for many other preparations1 the india rubber is 8masticated0 in special apparatus4 ,the machine consists of a fixed cylinder within which is a corrugated roller set eccentrically and rotated by power4 ,the perfectly dry sheets in the masticator are pressed and rolled and ground and produce a mass of even consistency4 ,here the welding or cohering action again appears in its fullest development4 ,the perfect dryness of the mass enables it to keep reuniting as fast as divided4 ,the action is assisted by the heat generated1 which is not inconsiderable4 ,sometimes the caoutchouc is warmed before introduction1 and sometimes the roller is heated by passing steam through it4 ,illustration3 ,,masticating ,,machine4 ,the masticating machine the ,french picturesquely term the wolf 7loup7 or devil 7diable74 ,it is given from sixty to one hundred turns a minute1 and a machine large enough to treat fifty pounds of gum in a charge1 requires five horse-power to drive it4 ,in it the sheeted gum is ultimately brought to the state of a perfectly homogeneous dark brown translucent mass4 ,the masticated rubber is peculiarly amenable to mechanical and chemical treatment4 ,it can be shaped by heat and pressure1 and it is the most soluble form and is used for making cement and solution1 and is moulded into blocks for the manufacture of sheet and thread rubber4 ,in the process neutral body pigments1 such as oxide of zinc1 or soluble transparent ones1 such as alkanine may be introduced2 easily decomposed matter cannot be incorporated on account of the heat4 ,in all these machines special provision is made to prevent any oil from getting into the gum4 ,there is no greater enemy to india rubber than oil or fats of any description4 ,the flanges in the masticator that roll just inside the bearing are for this purpose4 ,sheet rubber is made from the blocks of masticated gum by slicing4 ,a machine is used for the purpose which carries a knife which works back and forth in the direction of its length at high speed1 making two thousand cuts a minute4 ,the knife is kept wet by a stream of water1 and about sixty cuts are made per inch4 ,in many articles made from this sheet the marks of the cuts can be seen as a fine ribbing4 ,the appearance is familiar to many readers4 ,the sheet is often cut from rectangular blocks1 but cylindrical blocks are also used4 ,the latter are rotated in front of the knife edge and a long1 continuous sheet can thus be obtained4 ,the sheet rubber can be cut into threads on webbing and braid4 ,everyone has noticed that these threads are usually square4 ,the method of preparation accounts for it4 ,vulcanized sheet is now almost universally used for threads4 ,round threads however can be made by forcing softened or partly dissolved gum through a die4 ,it is from unvulcanized masticated sheet that toy balloons1 tobacco pouches1 etc41 are made4 ,it is the starting point for india rubber bands4 ,for the usual form of the latter article the sheet is cemented into a long tube which is afterwards cut transversely1 giving bands of any desired width4 ,to make any of these articles satisfactory vulcanization is imperative4 ,unvulcanized rubber for many years was used1 but it is now completely displaced by the vulcanized product4 ,sheet rubber is made as above2 is vulcanized by some of the absorption processes described in the chapter on vulcanization4 ,we now come to the second product3 regularly mixed and cured rubber4 ,its starting point is the washed india rubber from the washer and sheeter4 ,we have seen that the pure gum or caoutchouc is very sensitive to changes of temperature4 ,at the freezing point of water it is hard and rigid1 and at the boiling point is like putty in consistency4 ,there are several substances which can be made to combine with the gum and which remove from it this susceptibility to change of temperature4 ,the process of effecting this combination is called vulcanization1 and the product is called vulcanized india rubber4 ,sulphur is the agent most generally employed4 ,illustration3 ,,making ,,mixed ,,rubber4 ,in the factory the normal vulcanization is carried out in two steps1 mixing and curing4 ,the washed sheet india rubber which has not been masticated and which must be perfectly dry is the starting point1 and the mixing rolls shown in the cuts are the mechanism for carrying out the first step4 ,these are a pair of powerful rollers which are geared so as to work like ordinary rolls1 except that one revolves about three times as fast as the other4 ,they are heated by steam1 which is introduced inside of them4 ,the sheet is first passed through them a few times to secure its softness1 and then the operative begins to sprinkle sulphur upon it as it enters the rolls4 ,this is continued1 the rubber passing and repassing until perfect incorporation is secured4 ,about ten per cent4 of sulphur is added1 and a workman can take care of thirty pounds at a time4 ,this material is incompletely vulcanized4 ,it is in its present condition very amenable to heat and is ready for any moulding process4 ,generally it is rolled out or 8calendered0 into sheets of different thickness from which articles are made in moulds by curing4 ,these sheets are of especial interest to the reader as they are the material from which most small articles are made1 including rubber stamps4 ,this rolling of the mixed india rubber into sheets of definite thickness is done by special calendering rolls4 ,the product is termed 8mixed sheet40 ,in the mixing rolls the incorporation of other material is often brought about4 ,zinc white1 lead sulphide1 antimony sulphide1 chalk1 clay1 talc1 barium sulphate1 plaster of paris1 zinc sulphide1 lead sulphate1 white lead1 oxides of lead1 magnesia1 silica1 form a list of ordinary mixing ingredients4 ,these lower the cost of the finished material and are often serious adulterants4 ,for some cases the addition if not carried too far is not injurious1 or even may be beneficial4 ,a proper admixture renders the gum more easily moulded and treated in the shaping processes4 ,illustration3 ,,mixing ,,rolls4 ,the next step in the vulcanizing process is the heating of the mass1 which step is called 8curing40 ,up to a temperature in the neighborhood of that of boiling water the mixed rubber can be heated without change except as it is softened4 ,but if the heat is increased it begins to get a little more elastic and less doughy1 and eventually becomes 8cured0 or vulcanized4 ,the temperature for vulcanization is about #bhd ,f4 7#adj ,c474 ,the word 8about0 is used advisedly1 for it is not only a question of heat but of time of exposure4 ,after vulcanizing1 including the curing1 india rubber cannot be moulded to any great extent4 ,in the manufacturing process1 therefore1 it is before curing placed in the moulds1 heated1 shaped by pressure1 and by exposure to a higher heat in a steam oven called a vulcanizer1 is at once cured4 ,to prevent adherence to the moulds they are dusted over with ground soapstone1 and the rubber itself is often thus coated4 ,the methods of vulcanization and curing1 which may be of special use to the reader1 are given in the chapters devoted to that subject 7chapter ,,xi471 and in the one devoted to rubber stamps4 ,hard rubber1 termed ebonite when black1 and vulcanite when of other colors1 is simply vulcanized rubber containing a large percentage of sulphur added in the mixing process4 ,the manufacture of coated tissues is effected in several ways4 ,the following is a typical process4 ,a mixture of one part washed and sheeted india rubber with one part zinc white1 one fourth part sulphur1 and about one third part naptha is mixed into a dough-like mass and is spread upon the cloth by machinery4 ,the latter is simple4 ,it consists of a bare board arranged to move under a scraping bar4 ,the cloth is placed on the board and carried under the bar4 ,the coating mixture is fed on one side of the bar upon the surface of the cloth4 ,as it passes under1 a regulated amount1 according to the set of the bar1 adheres4 ,it is then dried by steam heat and recoated1 until ordinarily six coats1 each about one one-hundredth of an inch in thickness1 have been given4 ,three coats are given in each direction with intermediate drying4 ,the fabric is then cured by heat in vulcanizers4 ,sometimes the sulphur is omitted from the mixture and cold curing1 as described later1 is adopted4 ,when the goods are made up the seams are secured with rubber cement1 a thick solution of masticated gum4 ,such seams have to be vulcanized4 ,sometimes two such fabrics before curing or vulcanization1 are placed face to face and allowed to adhere and are then cured or vulcanized4 ,enough has been said in this outline of the manufacturer's treatment of india rubber to show that the first treatment requires machinery4 ,very little can be done with mortar and pestle1 although in making up solution these simple instrumentalities are available4 ,as a starting point for making small articles masticated sheet rubber and mixed sheet rubber are the staple materials4 ,the preceding steps are best accomplished in the factory4 ,,chapter ,v4 ,,india ,,rubber ,,stamp ,,making4 ,we have seen that india rubber cannot be cast in moulds4 ,except in special cases deposition from solution is not available4 ,it has to be shaped by a combination of heat and pressure4 ,when gently heated it softens and can be pressed in a mould4 ,as it cools it retains the shape thus given and is moulded4 ,this applies to all unvulcanized india rubber4 ,if mixed rubber is moulded and heated to a higher temperature without removal from the mould the curing process is brought about and the rubber may be not only moulded but cured and the product is moulded vulcanized india rubber4 ,the mixed sheet whose manufacture is described in chapter ,,iv4 7page #db7 is the starting point in rubber stamp making4 ,it is made for this purpose by the manufacturers4 ,when the material is examined it looks like ordinary white india rubber1 being firm in texture and quite strong4 ,on heating to #bhj ,f4 to #bij ,f4 7#acg ,c4 to #adc ,c47 it begins to become 8cured10 and if in a thin sheet one to ten minutes are sufficient for the process4 ,as the heat is applied the india rubber first softens and becomes much like putty4 ,it can now be pressed through the smallest orifice and will fill up the finest details of anything it is pressed against4 ,it is at this point that pressure must be applied to drive it into the interstices of the mould4 ,as the heat continues it begins to lose its doughy or putty-like consistency4 ,this marks the reaction of the vulcanizing materials4 ,they gradually combine with and change the nature of the caoutchouc4 ,the rubber while still quite soft is elastic4 ,if pressed by the point of a knife it yields1 but springs back to its shape when released from pressure4 ,the india rubber is vulcanized4 ,on removal from the mould it will be found to reproduce its smallest detail4 ,the color and appearance have not changed much1 but its nature and properties are now those of vulcanized rubber4 ,it is unaffected by heat or cold within ordinary ranges of temperature1 and if the india rubber is of good quality and made by a proper formula it will last for years4 ,illustration3 ,,simple ,,vulcanizing ,,press ,,for ,,rubber ,,stamps4 ,the first thing to be described is the mould1 which includes the arrangements for pressing the sheet of india rubber while heated4 ,a small press is needed for this purpose4 ,it may be of the simplest description1 and as an example of a home-made but perfectly efficient one the illustration may be referred to4 ,the base of the press is a piece of iron1 if heat is to be directly employed4 ,where a chamber vulcanizer is used both base and platen may be of wood4 ,but from every point of view iron is the best4 ,it lasts forever1 admits of direct heating1 and does not split1 warp1 or char4 ,through two holes drilled near its opposite sides two ordinary bolts are thrust4 ,it is best to use flat headed bolts1 and to countersink a recess for the heads in order to keep the bottom level4 ,the heads may need to be filed off so as to reduce their thickness1 in order to secure this object4 ,the bolts may be soldered in place4 ,one thing should be carefully watched for--the bolts should be set true so as to rise vertically from the plane of the base4 ,the platen is best made of iron1 cut of the shape shown4 ,this is an excellent disposition of the screw-bolt slots1 as by swinging the right end of the platen back it can be taken off without removing the nuts and lifting it over the ends of the screws4 ,besides the two nuts fitting the thread of the screws it is well to have half a dozen extra ones larger than the others1 which will slip easily over the bolts1 so as to act as washers4 ,the object of these is to adapt the press to objects of different thickness4 ,the thread upon an ordinary bolt does not extend clear to the head1 but by slipping on some loose nuts the plates can be forced together if desired4 ,this press can be simplified4 ,both base and platen can be made of wood1 the platen being simply bored for the bolts1 and the latter driven tightly through the holes in the base so as to retain their place4 ,even this can be improved on as regards simplicity4 ,two blocks of wood screwed together by two or more long wood screws may be made to do efficient work4 ,one trouble is apparent with all these devices1 and that is the want of parallelism of the opposed planes4 ,the base and platen may be true and parallel or they may not4 ,perhaps the simplest way of securing this is the best4 ,it consists in placing across the base two distance pieces1 which may be slips of wood4 ,these must have perfectly parallel faces4 ,as the press is screwed up they will be gripped between the platen and base and will not only ensure their parallelism but will keep them at an exact distance apart4 ,such distance pieces are shown in the same cut4 ,pieces of printers' 8furniture10 spaces1 or 8quads10 may be used for this purpose4 ,they should not be fastened in place if there is need to adapt the press to more than one thickness of material and matrix4 ,the above described apparatus is a vulcanizing press4 ,a further improvement in it may be effected by the use of spring pressure4 ,two strong spiral springs may be dropped over the bolts1 the nuts being screwed on above them1 or a powerful spring of flat brass or steel ribband bent into the shape of a shallow letter ,v may intervene between nuts and platen1 the centre of the bend bearing against the centre of the platen4 ,as regards the strength of the springs there is this to be said4 ,the distance pieces will prevent a spring that would ordinarily be too powerful from doing any harm4 ,such distance pieces should be used1 as the springs must be based upon giving a pressure of many pounds per square inch of surface to be acted on4 ,they should have a range of an eighth of an inch or more4 ,the greater the range the more evenly will they work4 ,the next cut shows an excellent little screw press1 that is made for the purpose of pressing vulcanizing flasks4 ,this is so simple that it will suggest to the mechanical reader how he can make a single-screw press1 which is by far the most convenient to use4 ,in the stationery stores very small model cast iron copying presses designed for use as paper weights are sold4 ,they are excellent for a limited amount of small sized work4 ,illustration3 ,,vulcanizing ,,flask ,,clamp4 ,a large sized gas heated press1 such as made for the purpose of manufacturing rubber stamps1 is shown in the next cut1 p4 #ec4 ,its construction is obvious4 ,it is termed by the trade a vulcanizer4 ,its manipulation will be given further on4 ,type are generally the object to be copied4 ,these are best set up with high quads and spaces4 ,naturally rather a large type is chosen1 with extra wide spaces between the letters4 ,some advise rubbing the type faces full of hard soap1 afterwards brushing off the face1 leaving the hollows filled4 ,sometimes wax is recommended for the same purpose4 ,this prevents the plaster of the matrix entering so deeply into the cavities of the letters4 ,illustration3 ,,gas-,,heated ,,stamp ,,vulcanizer4 ,the type forming the model to be reproduced1 is locked in a frame4 ,two pieces of printers' furniture or other wooden strips screwed together by wood screws at their ends will answer for a locking frame for small inscriptions4 ,the model to be copied need not be type1 but any desired relief may be used1 such as an electrotype1 a stereotype1 an engraving or another rubber stamp4 ,in any case it is to be placed upon a flat surface1 best an 8imposing stone0 or piece of marble1 with the inscription upwards4 ,on each side of it distance pieces reaching about one-eighth inch above its upper surface are to be placed4 ,the next shaping appliance is the matrix or mould1 or reverse of the model which is to be copied4 ,this in the case of rubber stamps is properly called the matrix4 ,those who have witnessed the stereotyping of a large daily newspaper have seen the matrices of the type made of paper and paste1 the whole mixture being termed 8flong40 ,such a matrix is required for rubber type1 but paper is rather too susceptible to heat although good work can be done with it4 ,it also does not enter as deeply into the cavities of the type as is desirable4 ,as a rule a fine quality of plaster of paris is to be recommended4 ,what is sold as dental plaster is the best1 but common plaster can be used4 ,it is mixed with water or with a solution of gum arabic or dextrine in water4 ,for the latter enough gum should be added to make the mixing solution as thick as thin syrup4 ,a piece of iron1 perfectly flat and true1 is now to be taken1 large enough to more than cover the inscription to be copied4 ,upon its surface a putty made of the plaster and the liquid used in mixing is to be spread4 ,this should be rather stiff4 ,the surface of the iron should not be too smooth as it is desirable that the plaster should adhere well on setting4 ,the plaster should be smoothly spread to a depth of three-sixteenths or a quarter of an inch4 ,it is best applied with a palette knife or trowel1 although a table knife will answer perfectly4 ,if its surface does not become smooth it can be made so by applying a little of the solution with the knife or trowel4 ,before this has been done the model must be oiled4 ,olive oil or other clear oil is applied to all parts of the type faces1 and the excess is then wiped off and cleared out of the interstices with a piece of blotting paper4 ,next the plate with the plaster is inverted and is pressed steadily down upon the model until it strikes the distance pieces4 ,it is left to set4 ,in about ten minutes it can be raised1 when it will be found to give a beautiful impression true to the smallest detail of each letter4 ,it has been said that water may be used as the mixing fluid4 ,if this is done it is well to strengthen the mould by saturating it with an alcoholic solution of shellac1 after it has dried thoroughly1 best for a few hours in an oven4 ,this operates to strengthen the small projections that are liable to crumble or to break off in use4 ,the dealers in rubber stamp supplies sell a lever press for conducting the operation of producing the matrix4 ,the type is locked in a special chase1 which is carried on a bed that travels under and out from under the platen of the press upon rollers4 ,from each corner of the chase in which the type model is locked1 a pin rises which is encircled by a spiral spring4 ,a square frame of flat iron with holes at the corners for the pins to pass through1 rests upon these springs well above the type4 ,the pins pass through holes in its corners4 ,the matrix plate with its coating of plaster is placed upon this frame1 which supports it above and not touching the type4 ,the whole is now rolled under the press and the lever pulled to produce the impression4 ,as the pressure is released the frame with the matrix is raised from the type by the action of the springs4 ,this can be done immediately1 and before the plaster has set4 ,it is almost impossible to raise it by hand with the requisite steadiness4 ,the same chase with corner pins and springs can be used in a screw press1 the one press answering for making the matrix and for moulding and curing the stamps4 ,the plaster matrix can also be made by casting from a thinner mixture of plaster and water4 ,after the type has been set up1 or the model has been selected and placed face up and horizontal1 a little ridge or projection must be made all around it4 ,paper can be pasted around it1 and wound with thread for this purpose4 ,it is oiled and wiped off as before4 ,the plaster is now mixed with water to the consistency of cream1 and is poured upon the model until it lies even with the projecting ledges or paper border4 ,in an hour or less it can be removed4 ,if water is used the mould should before use be treated with shellac solution as already described4 ,the plaster may also be mixed with gum arabic solution1 or with three to ten per cent4 of powdered marshmallow root4 ,this increases its toughness4 ,what is known as the oxychloride of zinc cement appears to the author to be far preferable to common plaster of paris4 ,it is a trifle more expensive1 but it costs so little that it is well worth trying4 ,it is made by mixing oxide of zinc with a solution of zinc chloride4 ,no particular strength of solution or proportions are prescribed2 the zinc chloride solution should be a strong one1 and the mixture should be of about the consistency of soft putty4 ,zinc chloride may be bought as a solid substance or in strong solution4 ,the latter answers for the mixing directly4 ,it may also be simply made by dissolving metallic zinc in strong hydrochloric acid4 ,the manipulation is exactly the same as with plaster of paris4 ,the manufacture of papier mach and of other matrices is given in a special chapter4 ,for all ordinary purposes the plaster or cement matrices are ample4 ,the stamp is made from the mixed uncured sheet rubber1 whose preparation in the factory1 including the operation of calendering it into sheets1 has already been described4 ,the best advice the reader can be given is not to attempt to make it except as a matter of interest and experiment4 ,it can be purchased especially prepared for stamps from the dealers in india rubber4 ,a piece is cut from the sheet large enough to cover the face of the matrix4 ,it should have a perfectly smooth surface1 without cloth wrapper marks sometimes found impressed on it4 ,the sheet as received from the maker is about one-eighth of an inch thick4 ,it is thrown into a box of powdered soapstone or talc to secure a coating of the same on both sides4 ,a little is dusted over the matrix and the excess is blown off4 ,the matrix is now placed upon the base of the press1 and heat is applied4 ,to carry out the process most simply the press if of metal may be placed upon a support over a gas burner or kerosene lamp1 or even on a kitchen range or stove4 ,it will in a few minutes become warm4 ,the sheet of india rubber is now dusted off and is placed in the press upon the matrix4 ,the platen of the press is screwed down upon it4 ,as the india rubber becomes hot it begins to soften and flow4 ,by the action of the screw of the press it must be forced down from time to time as it softens4 ,this drives the putty-like material into all the interstices of the mould4 ,the excess escapes from the sides of the tympan in cases where the latter is of restricted area4 ,the press theoretically should be heated to the vulcanizing temperature1 which is #bhd ,f4 7#adj ,c474 ,in practice the heat is not determined with a thermometer4 ,the operator learns by experience how much heat to apply4 ,the regulation type of gas heated press or stamp vulcanizer is shown in the illustration on page #ec4 ,as some of the india rubber is sure to protrude1 the progress of the work can be watched from its action4 ,by pressing the point of a knife against it the period of vulcanization can be told4 ,before the material is heated it is elastic and resists the pressure of the knife2 as heat is applied it becomes soft like putty2 as the heat increases it again stiffens and becomes quite elastic4 ,at this point the press can be opened and the sheet and matrix can be taken out or the platen swung aside4 ,on pulling or stripping the sheet from the matrix it will be found to reproduce the model in elastic india rubber to the minutest detail4 ,illustration3 ,,oil ,,stove ,,for ,,heating ,,vulcanizers4 ,as regards the minor details there is something to be said4 ,distance pieces to gauge the thickness have been recommended for the home-made press1 page #dh4 ,care must be taken to have these low enough to provide for enough excess of material to produce a good impression4 ,for ordinary stamp work they should allow about one-sixteenth of an inch for the 8squeeze40 ,it will be seen that by using the distance or gauge pieces both for making the matrix and for moulding and curing the stamp1 absolute parallelism of surfaces will be secured4 ,the reader will have noticed in the description and will find at once in practice that the press has to be screwed up as the rubber softens4 ,where heavy iron presses are used the large mass of heated iron comprised in the platen of the press instantly heats the upper surface of the india rubber sheet and the heat immediately penetrates into it1 while the heated matrix heats it from below4 ,thus it softens at once1 and the press is directly turned down and the india rubber is driven into the mould and curing at once begins4 ,but where small presses are used this manipulation is not so easy4 ,for such the springs mentioned on page #ea1 are highly to be recommended4 ,the matrix and india rubber can be put into the cold press1 and the tympan with intervening springs can be screwed down so as to compress them4 ,then on applying heat the moulding takes place automatically4 ,with a hot press and good sheet a period of three to ten minutes is ample for moulding and curing4 ,instead of sprinkling with talc the matrix may be oiled and sprinkled with plumbago and afterwards polished with a brush4 ,this is not so clean a material as talc and is not to be recommended for general use1 especially as oil is a bad substance to bring in contact with rubber4 ,the distance or gauge pieces whose use has been recommended are not necessary where presses working truly parallel as regards their opposing faces are used4 ,but where home-made apparatus is used they will be found a valuable addition4 ,in describing the simple press it was said that it could be made of wood4 ,it is evident that a wooden press could not be used for direct heating4 ,such a press must be used in a hot chamber or vulcanizer1 properly so called4 ,originally rubber stamps were generally made in chamber vulcanizers4 ,the next cut shows a combined matrix making1 moulding and vulcanizing apparatus of very convenient and compact form and adapted for rapid work4 ,as the press stands in the cut the matrix press is seen in front4 ,a box or chase is carried under its platen by two trunnions1 so as to be free to oscillate to a limited extent4 ,the type model is secured in this box4 ,above this box or chase is a cross-bar with screw and platen attached1 connected at will to two standards or pillars1 so as to constitute the matrix press4 ,a matrix plate swings on a hinge joint between the two presses4 ,the hinge-pin is removable4 ,its ends can be seen projecting to right and left of the press columns4 ,the hinge is at such a height that when the matrix plate is swung forward over the type box it will rest upon it in a nearly horizontal position4 ,the pivoted box will adjust itself so as to come into parallelism with the plate4 ,illustration3 ,,matrix ,,making1 ,,moulding ,,and ,,vulcanizing ,,apparatus4 ,when the matrix plate is swung back it falls upon the base plate of the vulcanizing press seen in the rear4 ,in use the composition used for the matrix is spread upon the matrix plate1 which may for this purpose be removed from the apparatus4 ,it is replaced and the hinge-pin is pushed home4 ,this is done with the composition coated side facing the front of the apparatus as it stands in the cut4 ,the plate is then swung forwards1 the platen of the matrix press being turned forward out of the way1 and is pressed down upon the type or other model that rests in the type box4 ,if desired the press is used to force it home4 ,the cross-bars of both the presses are arranged to swing each one on one of the pillars1 so that the platens are turned to one side out of the way of the matrix plate as it is swung back and forth4 ,the pressure is released and the platens are turned aside4 ,the matrix plate is swung over to the rear upon the bed-plate of the vulcanizing press4 ,here it lies with the composition-matrix upwards4 ,a lighted lamp1 either alcohol or gas1 is placed beneath the bed-plate of the vulcanizing press on which the matrix rests4 ,this quickly dries it and brings it to a good curing temperature4 ,the cross-bar and platen may be swung over it during the heating so as to be heated at the same time4 ,the matrix is talced when dry and hot2 the mixed sheet itself talced1 is placed upon the matrix1 the platen is screwed down upon it1 and in a minute or two the moulding and curing is completed4 ,illustration3 ,,rubber ,,stamp ,,vulcanizer4 ,a vulcanizer1 properly speaking1 is a vessel arranged to heat to a definite degree any desired articles which are to be cured4 ,the favorite type have been the steam vulcanizers4 ,if steam is generated from water at a constant pressure1 other things being equal a constant temperature will be produced4 ,by raising or lowering the pressure the temperature can be made to rise or fall4 ,a steam vulcanizer is a tightly sealed vessel which contains water and which is provided with a thermometer or a pressure gauge as well as a safety-valve1 safety disc or safety plug4 ,by keeping the gauge at constant pressure or by keeping the thermometer constant the temperature can be limited and kept steady4 ,the following table gives some pressure in pounds per square inch with temperatures corresponding to steam of such pressures3 ,lbs4 per square inch4 ,temp4 ,fahr4 ,temp4 ,cent4 #de4eab #bge #ace #eb4edh #bhd #adj #fj4ddb #bic #ade #fg4djh #cjj4b #adi ,the illustration1 p4 #fd1 shows a vulcanizer of modern type made for rubber stamp work4 ,in some recent vulcanizers the water and steam are excluded from the vulcanizing chamber1 being contained within double walls forming a steam jacket and maintaining a constant heat within the chamber4 ,these illustrate a point that has been much misapprehended1 namely that curing is independent of pressure or atmosphere4 ,because vulcanizers have generally been filled with steam at high pressure many have supposed that the steam or pressure had something to do with their action4 ,the fact is that it is only the heat due to the steam at such pressure that is instrumental4 ,steam is a very powerful radiator and absorber of so called radiant heat4 ,for this reason an atmosphere of steam maintains all parts of the vulcanizer at an even temperature and is to that extent advantageous4 ,its presence and the pressure it generates are not by any means required for vulcanizing4 ,its pressure is entirely without effect4 ,illustration3 ,,steam ,,jacket ,,vulcanizer4 ,to use a steam vulcanizer1 water is introduced1 the article in the press or mould is placed in it1 and the top is secured4 ,heat is then applied1 best if on the small scale1 from a ,bunsen gas burner gas1 or oil stove4 ,either the pressure gauge or thermometer may be watched1 and the flame turned up or down to keep it at the proper temperature4 ,moulding cannot be executed in the ordinary closed chambers4 ,the press must first be heated to the temperature of boiling water or thereabouts and the moulding is then effected by screwing down the mould screw1 upon the sheet and matrix4 ,it is then placed in the vulcanizer and cured4 ,the manufacturers supply gas regulators which automatically regulate the gas supply4 ,these are worked by the steam pressure4 ,if any one wishes to study the practical manipulation of small steam vulcanizers he can see them in use at any dentist's office4 ,there is no need of a steam vulcanizer for ordinary stamp work4 ,the hot press system already described answers every purpose and is in use by the most advanced manufacturers for thin sheet work4 ,but if a wooden moulding press is used then it must be heated in a vulcanizer or some kind of oven or hot chamber4 ,a very simple and reasonably satisfactory oven or air bath can be made from a flower pot and a couple of tin plates4 ,a plate larger in diameter than the mouth of the flower pot forms the base of the apparatus4 ,this is supported on a stand over the gas lamp or other source of heat4 ,a smokeless flame or one depositing no lampblack should be used4 ,alcohol or a kerosene oil stove illustrated on page #ei are excellent4 ,on this plate a smaller plate is inverted1 which latter must be so small as to be surrounded by the flower pot and to be included within it when the pot is placed over it like an extinguisher4 ,illustration3 ,,flower ,,pot ,,vulcanizer ,,on ,,stand4 ,a chemical or round stemmed thermometer is arranged to go through the aperture in the upturned bottom of the pot4 ,this may be hung from a support or it may be secured by passing through a hole in a cork or block of wood4 ,its bulb should be near the part of the chamber to be occupied by the mould or press4 ,the press with the article to be cured is placed upon the inner plate4 ,the temperature is maintained at the proper point by regulating the heat1 and all the conditions for excellent work are supplied4 ,the disposition of the apparatus is shown in the cuts4 ,illustration3 ,,interior ,,of ,,flower ,,pot ,,vulcanizer4 ,another arrangement equally simple is given in the next cut4 ,an iron kettle has a layer of type metal or lead poured an inch thick cast within it upon its bottom4 ,a thermometer passing through a hole in the cover enters a cup of glycerine that stands upon the bottom4 ,this gives the temperature4 ,the object of having a thick or a double bottom is to prevent excessive radiation of heat from any one part4 ,the essential condition for good operation is to maintain an even temperature throughout the chamber4 ,illustration3 ,,fish ,,kettle ,,vulcanizer4 ,the thermometer is not an absolute necessity4 ,by removing the press from time to time and inspecting the overflow of india rubber the progress of the operation can be watched4 ,an extra piece of india rubber may be placed on a piece of wood by the side of or upon the wooden portion of the press1 and its condition can be taken as the criterion4 ,pressure with the point of a knife will tell the vulcanizing point4 ,by the press system of curing1 a heat far above the vulcanizing temperature may be made to do good work by a very short application4 ,there is however danger of burning the work if left in too long4 ,if the air-bath with thermometer or the steam vulcanizer is used1 and the heat is kept down to the proper curing temperature1 there is no danger of burning the india rubber even if the curing is considerably prolonged4 ,as the flower pot has often to be lifted off for introduction or removal of the press1 and as it gets quite hot1 a holder of some kind is requisite4 ,a piece of heavy blotting paper is very convenient for this purpose4 ,the flower pot system with thermometer can be further simplified by being used on a stove or range4 ,a china saucer inverted1 or some similar support1 should be placed under the pot4 ,a part of the stove at very low heat will suffice4 ,the kettle vulcanizer1 can also be placed on a stove so as to dispense with gas or oil4 ,finally1 as the last step in simplifying the work1 a stamp can be made without any special apparatus beyond a hot flat iron4 ,the matrix may be placed on a stove where the heat is rather low1 the talc-coated mixed rubber sheet placed upon it1 and on this a hot flat iron4 ,in a few minutes if the heat is sufficient the stamp will be finished4 ,a few words may be said about the type4 ,high spaces and quads between the letters should be used1 such as will come up to the shoulder of the type1 as has been said4 ,but a very nice effect is produced by using low quads between words4 ,this leaves each word elevated by itself1 producing a good appearance4 ,autograph stamps are made from a model cut in wood by a wood engraver4 ,the autograph is written in some form of copying ink upon a piece of paper1 and is transferred by moistening and pressure to a block of wood4 ,with an engraver's tool the wood is cut away from the lines1 as the block is routed after the inscription has been 8outlined40 ,the woodcut is used as a model for making a matrix4 ,it is evident that an autograph of fair quality could be obtained from a chalk plate4 ,but in rubber stamp work to get good results certain essential parts should be of the best4 ,these parts include the mixed rubber1 model and matrix4 ,a departure from excellence in any of these tends to the production of an inferior stamp4 ,what is known as a 8healthy cure0 is above all essential to the appearance of the product4 ,the stamp thus made is attached to a wooden handle by common glue or by one of the rubber cements given in chapter ,,xvi4 ,,chapter ,,vi4 ,,india ,,rubber ,,type ,,making4 ,india rubber type are often used to set up different inscriptions in wooden handles1 or different date figures in rubber stamps4 ,the latter are in such cases made with slots or recesses to receive them4 ,rubber type are much shorter than regular type1 and as a rule are larger in the body in proportion to the face of the letter4 ,where only a few are required the following process is the simplest way of making them from mixed rubber sheet4 ,the type which are to be copied are set up on a level base or imposing stone1 and quads or spaces are put between them4 ,high quads and spaces should be used2 otherwise they should be pushed up until even with the shoulders of the type4 ,after oiling the faces a matrix is produced exactly as described for stamps4 ,before it has set quite hard the plaster or cement is cut off so that it will just fit within a little 8flask0 or frame4 ,the latter may be made of tin or wood and may be rectangular or circular1 provided it is large enough to include within its area the full working face of the matrix4 ,it should be about half an inch or five-eighths of an inch deep4 ,its object is to prevent the softened india rubber from spreading1 so as to secure the requisite height of the type produced4 ,illustration3 ,,india ,,rubber ,,type ,,mould4 ,a piece of wood or metal is cut so as to fit closely within this frame like a plunger4 ,it is provided with shoulders or cross pieces1 so as to limit the depth to which it can be inserted4 ,it will be seen that when matrix1 flask1 and plunger are all put together a complete mould for a block of type is produced1 as shown in the illustration1 the matrix with its plate forming the bottom of the box4 ,after the flask is placed upon the matrix it is filled with the mixed uncured india rubber sheet4 ,as a matter of preference thick sheet is used1 but scraps of all shapes can be employed as it all fuses together4 ,the mould and matrix are of course first well dusted with talc powder4 ,the plunger is put on and the whole is pressed4 ,heat is next applied in a vulcanizer or hot air chamber1 such as the flower pot arrangement1 or in boiling water4 ,as the sheet reaches the boiling point #bab ,f4 7#ajj ,c47 the flask is removed and the plunger examined4 ,if it goes down to its seat without expelling any india rubber more of the latter is required and is accordingly inserted1 the plunger being taken off for the purpose4 ,the softened gum should ooze out around the sides of the plunger4 ,the whole is again put under pressure1 and the platen is screwed down1 and if all is right an excess of rubber showing itself1 the whole is put in the hot chamber1 the heat is raised to #bhd ,f4 7#adj ,c471 and is maintained there for half an hour4 ,it is almost a necessity to secure the matrix plate to the bottom of the flask4 ,this for a single operation may be done by screws1 or for several operations by hooks or catches4 ,when the curing is complete the mould is removed from the vulcanizer1 is allowed to cool and is opened4 ,the block of type will come out with perfect reproduction of the letters upon one side4 ,if all the directions have been followed as regards distance pieces1 level imposing surface1 etc41 both faces will be exactly parallel1 and any number of other blocks can be reproduced of exactly the same height1 not necessarily from the same matrix1 although one good matrix can be used many times4 ,the type have now to be cut apart4 ,this is done with a sharp knife which is kept wet4 ,it is worked with a sawing motion1 and if sharp and properly used will cut with regularity1 and smoothly4 ,type with knife marks on the sides are always unmechanical in appearance and seem to be 8home made40 ,the object of using high quads and spaces or of pushing them up1 will now be evident4 ,it secures the evenness of the general face of the block of letters1 which otherwise would have a deep depression between each pair of letters4 ,if the quads and leads are properly arranged1 the letters will project upwards from a smooth1 plane surface4 ,the dealers in rubber stamp maker's supplies sell special steel moulds for the purpose of making them4 ,this does away with all necessity for making matrices1 and making up a flask1 etc4 ,the general manipulation is that given above4 ,where many are to be made the regular mould is by all means to be recommended4 ,sometimes type are made by cementing single letters made by the stamp process upon wooden bodies4 ,,chapter ,,vii4 ,,the ,,making ,,of ,,stamps ,,and ,,type ,,from ,,vulcanized ,,india ,,rubber4 ,although all reference hitherto in the matters of stamps and type has been to their manufacture from uncured india rubber1 a good deal can be done with vulcanized and cured gum4 ,the stock that is known in the trade as pure gum1 such as is used for bicycle tyres1 for steam packing and the like1 can be made to yield to moulding to a certain degree4 ,it will not flow and unite as will the uncured gum1 but it is evident that in certain cases its stiffness is even an advantage4 ,thus with it1 rubber type can be made without any flask or frame4 ,the material has stiffness enough to support itself4 ,the manipulation is of the simplest4 ,a piece is cut out with a knife so as to be of proper thickness and size4 ,it should be a little thicker than will ultimately be required4 ,the two opposite surfaces should be smooth and parallel4 ,it is talced1 and placed in the press with the matrix beneath it1 and subjected to pressure by the screws being turned down4 ,it is then placed in the vulcanizing chamber and heated to about #bhd ,f4 7#adj ,c474 ,after it has become hot it softens a little4 ,the press is removed from the hot chamber and is again screwed down as hard as the matrix can stand4 ,this point is largely a matter of judgment4 ,the heat is largely indifferent as long as it is anywhere near the above temperature4 ,by one or two repetitions of the pressing and heating the softened india rubber can be made to take quite a deep impression from a suitable matrix4 ,it is allowed to cool under full pressure4 ,when removed from the press1 it will retain the characters4 ,it is evident that impressions in as high relief or as deep and clear as those yielded by uncured india rubber need not be expected4 ,but where the other cannot be had1 or where some experimental or temporary work only is on hand1 this process will be very convenient4 ,the material may be half an inch thick4 ,from such india rubber type can be cut with advantage4 ,old rubber can be thus used4 ,the writer has obtained excellent results from pieces of an old discarded bicycle tyre4 ,the great point is to apply a heavy pressure to the hot material4 ,many other articles can be thus produced extemporaneously4 ,at the same time it must be considered only a makeshift4 ,one who has used the soft1 easy flowing uncured gum would never be reconciled to the use of so rigid and difficultly moulded a material1 one too that can never be trusted to reproduce intricate moulds of considerable depth4 ,in the slow yielding of the half melted uncured gum1 so amenable to slight pressure1 a quality of availability is found that is missed in the other4 ,one is worked by main force where the other readily yields and takes the most complicated shapes4 ,by the above process stamps of such thickness may be made that they can be used without handles4 ,it is also useful for impressing a designation of any kind upon ready cured articles4 ,it suggests a very useful department of manipulation of india rubber4 ,the heating and moulding can be done also in a hot liquid bath such as described in chapter ,,xi4 ,,chapter ,,viii4 ,,various ,,type ,,matrices ,,for ,,rubber ,,stamps ,,and ,,types4 ,matrices for stamp moulds can be made by several of the methods used by stereotypers4 ,thus an electrotype could be taken directly from the face of the type4 ,there would be little or no utility in doing this where the simpler processes are available4 ,,papier ,,mach ,,matrices4 ,the stereotyper for daily newspaper work uses very generally the papier mach or 8flong0 process of reproducing the page4 ,this is also available for rubber stamp making4 ,the first requirement is paste4 ,this is made by softening twelve parts of whiting in forty parts of water1 letting it soak for an hour or more4 ,nine parts of wheat flour are added4 ,this is best mixed with a little water before adding to the main mixture4 ,it is then brought to the boil and seven parts of glue softened by soaking in twenty-one parts of water1 are added4 ,for each gallon of such mixture1 one ounce of white crystallized carbolic acid is added if it is to be kept for a long time4 ,the 8flong0 is made by pasting together1 one on top of the other1 a sheet of fine hard tissue paper1 three sheets of blotting paper 7about #bc pounds to the ream71 and a heavy sheet of manilla paper4 ,the pasting must be smooth and each layer must be pressed and rubbed down1 but not too hard4 ,it is very important to secure perfect smoothness and regularity1 and entire absence of air bubbles4 ,every printing office where the process is used has its own traditions as to the preparation of flong4 ,as a great deal depends on manipulation1 it would be well to endeavor to inspect its practical use in a newspaper printing office before making it4 ,ready prepared flong can also be procured4 ,the form of type must be very clean and there must be no paste on the tissue paper face of the flong4 ,the type are lightly oiled1 some powdered talc is dusted over the damp tissue paper face of the flong1 and the mass is laid face downward on the type4 ,with a stiff haired brush the paper is now beaten down against the type4 ,great care must be taken to beat vertically2 a slight side action will ruin the resulting matrix4 ,if the brown paper will not stand the beating1 a cloth may be spread over it4 ,the progress of the work can be watched by raising up a corner from time to time4 ,when sufficiently deep the last touch is given by the printer's planer4 ,this is a block of hard wood4 ,it is placed upon the back of the flong and is hammered down4 ,the operation is repeated until the entire area has been treated4 ,for much rubber stamp work the area would be so restricted that shifting would be unnecessary4 ,the work is then put into a heated screw press1 such as the vulcanizing and matrix press1 and is dried for a period varying from some minutes up to half an hour4 ,some blotting paper is advantageously pressed on top of the whole in the press while drying4 ,the press is opened1 the flong removed1 and dried in an oven4 ,it is kept under a piece of wire net while drying to keep it flat4 ,the net may be of wire1 4#jfd inch thick1 with six meshes to the inch4 ,this baking is not strictly necessary for rubber stamp work4 ,this gives a matrix which may be used as rubber stamp moulds4 ,in use it is recommended to place a piece of smooth tin foil over it4 ,this tends to give a smoother surface to the rubber4 ,,struck ,,up ,,matrices4 ,didot's polytype process may be advantageously used for producing type metal matrices4 ,the following is the method of applying it4 ,the type form is firmly locked and is backed up by and secured to a solid block of wood4 ,it is suspended in a sort of gallows frame with the face of the type downward and exactly level a few inches above a table4 ,underneath it a shallow tray is placed1 into which some melted type metal is poured4 ,the melted metal is carefully watched4 ,the block and type are held by a catch so as to be released at will4 ,just as the type metal is on the point of solidifying1 the block is released and drops upon the metal in the tray4 ,the type should be slightly oiled4 ,the force of the blow produces a matrix in the metal1 and the form can at once be removed4 ,it is well to have accurately adjusted distance pieces for corresponding striking pieces on the type block to impinge upon4 ,the process is highly spoken of1 especially for small forms such as those mostly required for rubber stamps4 ,,chalk ,,plates4 ,the base for this form of matrix is a metal plate whose surface is slightly roughened with sand-paper4 ,it is next rubbed over with white of egg1 and flooded with the chalk wash made as follows3 ,flong paste 7described under ,papier ,mach ,matrices1 page #hj71 six ounces2 whiting1 twenty-four ounces2 water1 three pints4 ,the whiting is softened by soaking for an hour or more4 ,the whole must be intimately mixed4 ,it should cover the plate to the depth of one-thirtieth to one-twentieth of an inch4 ,the plate is dried in a perfectly horizontal position4 ,when dry the design or writing1 etc41 is made with a smooth steel point1 the lines being carried clear through the white layer to the metal4 ,the mould is now baked at a temperature well above boiling water2 as high as #cib ,f4 7#bjj ,c47 may be reached without harm4 ,if the coating seems too thin1 an extra coat can be given between the lines especially over the larger areas4 ,this must be done before the baking4 ,a pipette may be used for putting on this coat4 ,this deepening has the bad effect of increasing the chance of the coating stripping from the metal4 ,the matrix thus prepared is used in the press just as is the ordinary plaster matrix4 ,it is suited for reproduction of autographs1 scrip1 diagrams1 etc4 ,,chapter ,,ix4 ,,the ,,making ,,of ,,various ,,small ,,articles ,,of ,,india ,,rubber4 ,india rubber can be so readily shaped in moulds and the latter are so readily made of plaster of paris that any one who is interested in such things will find endless amusement in working out different designs4 ,before suggesting any specific articles the following are the general points to be kept in mind4 ,the material may be uncured mixed sheet of any thickness4 ,as we have seen this material when heated and pressed runs together4 ,it can be forced into any shape by comparatively slight pressure4 ,so exactly does it reproduce the smallest line or mark1 that care must be taken to have the moulds very smooth and free from defect4 ,powdered soapstone is used to prevent adherence to the mould1 but great care must be taken not to mix it among the pieces of the india rubber1 where several are used in one article1 as it will prevent their coalescing or running together4 ,another point is to contrive to introduce the proper quantity of rubber4 ,the aim must be to have a slight excess1 but to avoid waste this should be as little as possible4 ,unless some rubber is squeezed out there is no certainty that the mould has been filled4 ,any projecting 8fins0 from the overflow are cut off with a knife or scissors after the article is removed from the mould4 ,plaster of paris or dental plaster mixed with dextrine or gum arabic water or the zinc oxychloride cement1 already described1 is to be recommended for the moulds4 ,they should be made1 if deep1 in frames or 8flasks0 of tin1 as plaster if unsupported is liable to split open when the rubber is forced home4 ,for many articles the hot press can be used4 ,such articles are mats and other thin flat pieces4 ,the rubber stamp sheet is a good material for them4 ,for thicker articles a thicker sheet can be used1 and sheet of any gauge can be procured from the maker4 ,much of what has been said about india rubber type applies to the making of miscellaneous shapes4 ,it will also be understood where wooden moulds are spoken of that plaster1 or1 still better1 metal can be substituted1 and is to be recommended for nice work as the grain of the wood is very apt to show where the india rubber comes in contact with it4 ,suction discs and similar small articles into which an extra thickness of india rubber enters are best cured in a vulcanizer4 ,the flower pot arrangement is excellent for such4 ,the time for curing may be somewhat extended on account of the greater thickness of material to be acted on4 ,suction ,discs4--,for suction discs a mould is required which will produce a shallow cup with the edge feathered or reduced to a very slight thickness4 ,its outer surface should be raised in the centre so as to give a projection for attachment of the hook4 ,the discs are generally made small1 not over an inch in diameter1 as they are not reliable for any heavy service4 ,their principal use is to suspend advertising cards and light articles to the glass of show windows4 ,the following is a method of making a simple mould4 ,a hole to give the outside contour should be bored in a small piece of wood4 ,a marble which will exactly fit the hole is next required4 ,some plaster of paris is mixed with water and put into the bottom of the hole1 and the oiled marble is pressed down until the plaster rises and fills the entire space under the marble4 ,after it has set the marble is removed4 ,the proportions should be so arranged that the plaster will have risen at the sides within an eighth of an inch of the surface of the wood4 ,this gives the exterior mould4 ,for the cup or hollow a marble a shade too large to enter the hole may be used4 ,one or if necessary two thicknesses of mixed sheet rubber cut into disc shape so as to fit the hole are inserted in the block1 and the larger marble is placed on top and screwed down by the press4 ,heat is now applied in the vulcanizer4 ,when the thermometer indicates #bab ,f4 7#ajj ,c471 or better a little more1 the mould is withdrawn and the screws turned until the rubber is forced down and the excess begins to squeeze out between the marble and the wood1 which two should now nearly touch4 ,it is replaced and the heat is brought up to the curing temperature #bhd ,f4 7#adj ,c474 ,it is possible that a second screwing up may be needed4 ,the spring press is in such cases particularly convenient as it avoids the necessity for removing the press from the vulcanizing chamber4 ,after half an hour it will be thoroughly cured4 ,a hole is made through its centre from side to side thereof1 but not penetrating the disc1 and through this hole a brass nail is thrust and bent into hook form4 ,illustration3 ,,mould ,,for ,,suction ,,discs4 ,in the cut the correct shape for the mould and consequently for a suction disc is shown4 ,this can be easily secured where a disc already made is procurable by casting in plaster1 or1 with a little ingenuity the template for the mould and the plunger to be used instead of the marble can be whittled out of wood4 ,the lower body of the mould in such a case can be made of plaster of paris4 ,to secure the alignment of the two parts of the mould1 dowel pins1 indicated in dotted lines1 should be placed near the periphery4 ,the gum should be introduced in a lump near the centre1 in order that it may sink well downwards to the bottom of the mould before spreading laterally4 ,sometimes the tips have a recessed end4 ,this is secured by the use of a mandrel1 shown in dotted lines in the axis of the mould4 ,such discs are sometimes made to be cemented to arrows to be discharged against smooth surfaced targets1 to which they adhere on impact by atmospheric pressure1 giving rise to a very interesting game4 ,another use of suction discs is as photographic negative holders4 ,they can be fastened to a wooden handle and be attached by suction to the back of a negative under treatment4 ,for this purpose they should be at least two inches in diameter4 ,pencil ,tips4--,these are generally little cylinders of india rubber1 which fit into a tube that slides over the end of the pencil4 ,they can be thus simply made4 ,a hole is bored in a piece of wood the diameter of and a little more than the depth of the pencil tip4 ,a short cylinder that exactly fits the hole is required for plunger4 ,the gum is put into the hole in little discs1 or rolled up into a cylinder1 the plunger is placed on top1 and the mould put in the press4 ,it is shaped by pressure and cured as described4 ,sometimes the tips are cup shaped4 ,for these the mould is made in two sections fastened by catches or by pins set in the plaster as shown in the cut4 ,the hole is made larger at bottom than at top1 and at the top is a little smaller than the shaft of the pencil4 ,a plunger that nearly fits the small end is provided4 ,the india rubber is placed in the mould and heated4 ,when soft1 the plunger is forced down to the proper distance in the press and the article is cured4 ,care must be taken to give the plunger a good coating of talc1 and it must be made to sit vertically4 ,the arrangement of a cylindrical hole shown in the cut secures this result perfectly4 ,as distance piece a pin is passed through the plunger4 ,illustration3 ,,mould ,,for ,,pencil ,,tips4 ,cane and ,chair ,leg ,tips1 etc4--,by carrying out the process just described with larger moulds and of slightly different section very convenient tips for chair legs and walking canes can be made4 ,such tips can be modified in size and thickness to answer as covers for the mouths of bottles1 test-tubes1 etc4 ,corks4--,these may be made in moulds tapering from top to bottom4 ,the india rubber must be packed in with great care to secure as solid filling as possible4 ,a plunger is used that enters the larger end and is a very little smaller in diameter1 so as to descend a little way into the mould4 ,this distance determines the length of the cork4 ,as the perimeter of the plunger strikes the walls of the mould it cuts off almost completely the excess of rubber that has squeezed up past it4 ,an excellent modification of the mould is shown in the cut4 ,the upper part with parallel sides serves as a guide for the plunger4 ,it is a similar extension as the one recommended to be used for the plunger in the hollow pencil and chair leg tip moulds just spoken of4 ,illustration3 ,,mould ,,for ,,rubber ,,corks4 ,mats4--,these may generally be made in the hot press4 ,designs for them in great variety may be found in cut glass and pressed glass dishes4 ,many of these have patterns on their bottoms that can be moulded in plaster to serve as matrices4 ,cord1 ,thread and ,seamless ,tube4--,by placing the mixed india rubber in a cylindrical mould fitted with piston and with one or more round holes in the bottom1 the material may be softened by heat and forced out of the holes by depressing the piston4 ,this will form cylindrical thread or cord4 ,as it descends it may be received in a box of powdered talc and be afterwards cured4 ,by providing the hole with a mandrel seamless tubing may be thus made4 ,in making such the mandrel usually remains in place during the curing4 ,plenty of powdered talc must be used4 ,skeletonized ,leaves as ,models4--,these would form interesting models from which matrices could be made in plaster4 ,it would be possible to produce some very pretty stamps or mats from these and similar models4 ,after some experience inspection of any article will show how it was moulded4 ,the fin will indicate the joint in the mould1 and with this as a clew the mould can be almost certainly constructed like the original4 ,india ,rubber ,bulbs4--,bulbs and hollow articles generally1 such as dolls1 toys and the like1 cannot be made without special high pressure hollow moulds4 ,the general process consists in cutting out gores from mixed sheet as for a balloon4 ,the edges are coated with cement 7thick benzole or carbon disulphide india rubber solution7 and while the rubber is warm the seams are pressed and knitted together with the fingers4 ,a hole is left in one place through which some pure water or water of ammonia is introduced4 ,the bulb is now blown up with the mouth or otherwise1 and while inflated the hole is pressed shut4 ,this is often done with the teeth4 ,any projections around the seams are cut off with curved scissors4 ,the mould is of iron and in two halves4 ,powdered talc is applied1 and the bulb is placed in and shut up in the mould which it should exactly fill4 ,the mould is clamped together and the whole is put into a vulcanizer1 and the rubber is cured4 ,the steam and vapor formed by its liquid contents expand it and press it with great force against the sides of the mould4 ,after curing the mould and bulb are removed from the vulcanizer1 cooled by a shower bath of cold water1 the mould is opened and the bulb is removed4 ,often an iron pin is left projecting through the side during the vulcanizing1 which pin1 when withdrawn1 leaves the necessary aperture1 or it is perforated4 ,the bulbs are polished by tumbling in a revolving cylinder4 ,considerable skill and practice are needed to succeed in making hollow bulbs4 ,great accuracy is needed in cutting out the gores and in joining the seams4 ,,chapter ,x4 ,,the ,,manipulation ,,of ,,masticated ,,sheet ,,rubber4 ,the manipulation of pure sheet rubber is simple1 yet is liable to lead to disappointment4 ,when two pieces are laid face to face and cut across with a sharp knife1 or scissors1 the edges will adhere with considerable tenacity4 ,this may be increased by applying some thick solution of india rubber in a volatile solvent1 and by manipulating the sheets so as to bring the entire surfaces of the cuts together4 ,finally the material may be charged with sulphur by absorption or by ,parkes' process1 and cured in a glycerine or calcium chloride bath1 all of which are described in chapter ,,xi4 ,the same treatment will affect the cement used in making the joint also1 bringing about its vulcanization4 ,such in a few words is the main process in the treatment of this class of goods4 ,where it is desired to prevent adherence1 soapy water or powdered talc is used4 ,adherence may be produced between the surfaces of the sheets if they are clean1 by pressure and a little warmth4 ,the method of making toy balloons will give an example of how the article is dealt with by the manufacturer4 ,a pile of pieces of masticated sheet rubber is made4 ,every piece has one side coated with powdered talc1 and two talc-coated sides are placed in contact in each pair4 ,as they are piled up1 the outer surfaces of each pair are moistened with water4 ,a steel punch or die1 pear shaped in outline1 is used to cut down through the pile1 cutting all the pieces into that shape4 ,the pile is then taken apart in pairs4 ,the separation takes place between the wet surfaces1 the edges of each pair adhering slightly so as to enclose the talc-coated surfaces4 ,the neck is opened if necessary4 ,a rather weak or thin solution of india rubber in benzole is now brushed over the freshly cut edges4 ,by pulling out the centre of each piece the edges are brought into contact1 and adherence is produced4 ,if the ,parkes process of vulcanizing1 chapter ,,xi41 is employed they are cured to the slight extent necessary upon a tray coated with talc4 ,the balloons are then ready for inflation4 ,they are rather delicate articles to make except for immediate use as the thin material is liable to become over vulcanized4 ,in the chemical laboratory sheet rubber can be used for covering the ends of glass stirring rods4 ,these answer very nicely for cleaning out from beakers the last particles of a precipitate4 ,the sheet is cut of proper size and is bent around the end of the rod and cut off close with a pair of scissors4 ,it adheres where cut4 ,it is then pinched with the fingers to bring the edges into better contact and the operation is complete4 ,a slight heat makes it adhere better4 ,to connect glass tubes in setting up laboratory apparatus the same material was formerly used4 ,it was wrapped around the joint1 tied with thread and slightly warmed4 ,at present this form of connection is wholly displaced by ready made rubber tubing4 ,it is interesting to observe in all articles made from this sheet the marks of the original cutting knife4 ,these may be observed in inflated balloons1 as parallel lines running all over the surface1 and magnified by the expansion due to the inflation4 ,,chapter ,,xi4 ,,various ,,vulcanizing ,,and ,,curing ,,methods4 ,the regular methods of vulcanizing and curing can be departed from and good results obtained4 ,a few excellent methods differing essentially from the ordinary ones are described which will be of service to workers on the small scale1 as they enable one to dispense with vulcanizer and air bath entirely4 ,one type of curing process does away with the air or steam vulcanizer1 and substitutes1 as the curing agency1 a hot bath of liquid4 ,for this purpose a fluid is required that will not act injuriously upon the india rubber1 and which will give a curing temperature without boiling away4 ,one favorite liquid is glycerine4 ,this can be heated to the necessary degree and is an excellent substitute for the expensive apparatus often used4 ,for experimental work it is exceedingly convenient4 ,in use it is placed in a vessel of proper size and a thermometer is suspended so that its bulb dips into the liquid near one side and does not touch the bottom of the vessel4 ,the heat is applied by a gas burner1 alcohol lamp or oil stove4 ,of course the vessel may be placed on an ordinary cooking stove or range1 and the heat may be graduated and adjusted by moving it about until it reaches a part of the stove where the proper heat will be maintained4 ,the mould with its contents is immersed in the glycerine1 care being taken to see that it so placed as to assume the mean temperature of the liquid and not to be heated too hot4 ,this might happen if it stood on the bottom of the vessel1 so it is well to have it supported or suspended a little above it4 ,it is easy to see that the whole may be so arranged that the screw handle or pressure nuts of the mould will rise above the liquid4 ,in this case the press can be screwed down while the article is heating4 ,instead of glycerine a strong solution of some salt in water has been recommended4 ,a solution of calcium chloride1 or some other salt can be substituted4 ,either are very cheap and will be quite satisfactory4 ,another treatment which applies also to the mixing operation is by the sulphur bath4 ,sulphur is melted in an iron vessel and brought to a temperature of #bdh ,f4 7#abj ,c474 ,a piece of unmixed pure caoutchouc immersed in this bath will gradually absorb sulphur4 ,the case is almost parallel with the absorption of water or benzole by the gum4 ,the piece swells and thickens as it is acted on and eventually will contain enough sulphur for vulcanization4 ,it may absorb as much as fifty per cent4 ,the point of proper absorption must be settled more or less empirically or by successive trials4 ,after enough has been taken up the piece is removed and dipped into cold water1 which cracks the adherent sulphur so that it can be brushed or rubbed off4 ,this gives a piece of mixed rubber ready for moulding and curing4 ,it can be heated and moulded and may be cured as desired1 in a liquid bath1 hot press or vulcanizer4 ,it will be observed that this provides for the admixture of sulphur only2 no talc or other solid can be thus introduced4 ,the addition of these solids tends to make the rubber of a more attractive color and their use is not to be deprecated in all cases4 ,hence the sulphur bath process is not to be considered a perfect one4 ,in the sulphur bath the mixing and curing processes can be combined4 ,if the liquid sulphur is heated to the vulcanizing temperature1 #bhd ,f4 7#adj ,c471 a thin strip of gum immersed in it will be vulcanized completely in a few minutes4 ,a heating of several hours at the lower temperature will effect the same result4 ,the sulphur bath processes must be regarded as unsatisfactory4 ,it is not easy to feel that any dependence can be placed upon them as regards reliability or constancy of product4 ,the sulphur also will mostly effect the surface4 ,thin pieces may be satisfactorily treated1 but the same confidence cannot be felt as is experienced when specific amounts of ingredients have been mixed in with pure caoutchouc in a regular mixing machine4 ,the sulphur bath is of value to the experimenter1 enabling him to do his own mixing without expensive apparatus4 ,bromine1 iodine1 chlorine and nitric acid are vulcanizers4 ,a piece of sheet rubber dipped into liquid bromine is instantly vulcanized4 ,iodine and nitric acid have also been used in commercial work4 ,alkaline or alkaline earth sulphides can be employed in solution under pressure for vulcanizing4 ,at a vulcanizing temperature their solutions will answer for thin sheet very well4 ,polysulphides of calcium have thus been employed4 ,by simply lying embedded in finely divided sulphur at a temperature of #bcc ,f4 7#aab ,c47 as much as ten per cent4 of sulphur may be absorbed by thin sheet rubber4 ,this is one of the processes peculiarly suited for work on the small scale4 ,it may be used instead of the ,parkes process next to be described4 ,chloride of sulphur is an orange red mobile liquid of a peculiar and disagreeable odor4 ,it boils at #bgf ,f4 7#acf ,c474 ,it dissolves both sulphur and chlorine so that it is not easy to obtain it in a pure state4 ,if unmixed india rubber is exposed to its action it will quickly become vulcanized4 ,at ordinary temperatures the mixing action takes place1 though it is much accelerated by a slight application of heat4 ,it is quite possible that this action may be of use to the reader in his manipulation of india rubber4 ,thin sheet may be vulcanized by being immersed in a solution of this substance in bisulphide of carbon followed by slight heating4 ,the thin layer of caoutchouc left by evaporation of the chloroform solution of india rubber may thus be vulcanized so as to become comparatively strong and elastic4 ,where the same solution has been used as a cement or for patching overshoes and finishing the patch1 a vulcanization can thus be given to it4 ,the process is known as ,parkes' cold curing process4 ,a solution of one part of chloride of sulphur in forty parts of bisulphide of carbon is of good strength for rapid work4 ,a thin article needs but an instant of immersion4 ,it then is placed in a box or tray upon some talc powder and is heated to about #ajd ,f41 7#dj ,c474 ,one minute of curing will suffice4 ,it is advisable to wash off the articles afterwards in water or in weak lye to remove any traces of acid4 ,petroleum naptha can be used as the solvent instead of bisulphide of carbon4 ,the latter substance has an exceedingly disagreeable odor1 and its vapors must be considered rather injurious especially to those who are not accustomed to them4 ,when thick articles are to be cured by this process a much more diluted solution is used4 ,one per cent4 or less of the chloride of sulphur is the proportion used4 ,the object of this is to enable a longer immersion to be employed so that the interior will be affected before the outer layers become too much charged with the vulcanizing material4 ,in this short description of the ,parkes curing process hints for a useful method may be found4 ,the process is beyond doubt by far the simplest known for treatment of india rubber4 ,exactly what reaction takes place is unknown4 ,whether the sulphur or the chlorine is the acting vulcanizer has not as yet been determined4 ,its defect is that it produces surface action1 analogous to casehardening4 ,one method of avoiding this is to remove the articles from the sulphur chloride bath and at once to immerse them in water4 ,this prevents the rapid volatilization of the solvent and an equalizing of the absorption ensues4 ,,chapter ,,xii4 ,,the ,,solution ,,of ,,india ,,rubber4 ,india rubber presents some difficulties in its solution4 ,if a piece of pure gum just as received by the factory is placed in hot water it will swell and whiten after a while1 but will not dissolve4 ,if a similar piece is placed in benzole a similar but greatly exaggerated action takes place4 ,the piece if left to soak for a day or more swells enormously1 but very little solution is effected4 ,the swollen india rubber can be removed from the benzole in a single piece4 ,it will display all the layers and marks of the original piece which was perhaps of not one hundredth part of its volume4 ,some parts will be a perfect transparent jelly4 ,it has been found that masticated india rubber dissolves with comparatively little difficulty4 ,if the experimenter will place in a porcelain mortar1 the jelly-like mass obtained as above detailed1 and will rub it up thoroughly1 it will be effectually masticated4 ,this requires a little patience1 as the slippery material seems to elude the pestle4 ,yet eventually it will all be reduced to a perfectly homogeneous mass4 ,its action while being rubbed up is very peculiar4 ,at first no progress seems to be made4 ,after a little the lumps yield to the friction4 ,the rubber then begins to attach itself to the pestle and mortar1 and begins to be drawn out into ever changing webs and threads4 ,as the operation approaches completion the material makes a snapping1 crackling noise familiar to all rubber workers4 ,when complete there will be no lump left1 and the whole will be a uniform pulp4 ,if benzole or a volatile solvent has been used1 the rubber will easily be removed from the mortar with a spatula or palette knife4 ,if turpentine was the solvent it will be impossible to remove the last traces except after long standing or by solution4 ,if replaced in the original solvent it will now come into nearly or quite perfect solution4 ,this is the best way of masticating on the small scale4 ,it is almost impossible to masticate untreated gum in an ordinary mortar4 ,the dealers sell a special india rubber for the manufacture of cement and solutions4 ,this is so treated by mastication that it dissolves with great readiness4 ,it is also said that heating under pressure is used to dissolve it in some factories4 ,many solvents have been used and none work without some difficulty4 ,benzole1 coal tar naptha1 petroleum naptha1 carbon disulphide1 ether and chloroform1 oil of turpentine and caoutchoucin are the best known4 ,the naptha best suited for its solution is termed solvent naptha4 ,it has a specific gravity of 4#hej at #fj ,f4 7#ae ,c472 it boils at from #bdj ,f4 7#aae ,c47 to #bej ,f4 7#aba ,c47 and on evaporation should leave no more than ten per cent4 of residue at #cbj ,f4 7#afj ,c47 ,payen recommends a mixture of #ie parts bisulphide of carbon with #e parts of absolute alcohol4 ,commercial chloroform is apt to be too impure to act as a good solvent4 ,it is apt to contain alcohol mixed with it as a preservative1 which impairs its effectiveness4 ,some of these solutions are better suited than others for the deposition of thin layers by evaporation4 ,turpentine gives a very sticky and unmanageable solution1 which dries very slowly4 ,payen's solution and the chloroform and the benzole solutions may be cited as especially adapted for this purpose4 ,careful vulcanization by the cold curing method can be applied to articles made by such deposition from evaporation4 ,in the case of all of them some form of mastication for the india rubber is needed4 ,the simple mortar grinding of the gum swelled by the solvent is the only practical treatment without special apparatus4 ,when it is remembered that fixed oils are destroyers of vulcanized or unvulcanized india rubber it will be obvious how important it is to use pure solvents4 ,too great care cannot be taken to preserve the liquids pure and free from such matter4 ,a solid hydrocarbon may be used4 ,thus paraffin wax1 such as candles are made of1 when melted acts as a solvent4 ,the resulting liquid solidifies when it cools1 retaining an almost greasy feel4 ,boiling oil of turpentine is recommended by some for the solution of vulcanized india rubber4 ,phenyle sulphide1 it is stated1 will soften it so as to render it workable4 ,the latter discovery is credited to ,dr4 ,stenhouse4 ,it is stated that a solution or pasty mixture of one part of caoutchouc in eleven parts of turpentine with one half part of a hot concentrated solution of sulphur 7potassium sulphide7 gives on evaporation a film neither tacky nor soft1 a species of vulcanization taking place4 ,it is of much interest to note that an aqueous solution of india rubber has been proposed in which the vehicle is a solution of borax in water4 ,this is well known to be a solvent for shellac and other resins4 ,it has been recommended often as a vehicle for rubbing up india ink4 ,the ink made by mixing lampblack with the shellac solution is nearly waterproof4 ,a shellac varnish is given by the plain solution4 ,the experiments upon india rubber were published in a recent trade paper4 ,one method of making the solution is as follows4 ,a solution of borax two fifths saturated is made by adding to two volumes of saturated solution three volumes of water4 ,to this is added a solution of india rubber in benzole or other hydrocarbon of such strength and in such quantity as to contain from three and one-half to four and one-half per cent4 of india rubber referred to the borax solution4 ,it is now vigorously shaken and heated to #abj-adj ,f4 7#di-fj ,c47 and the agitation1 not too violent1 is continued until it cools4 ,ceara or ,madagascar rubber answers best2 ,para is not so good for this formula4 ,this may be termed the indirect or emulsion method4 ,for direct solution from two to three volumes of water may be added to three volumes of saturated borax solution4 ,the india rubber is added in extremely thin shavings and the solution is heated4 ,for weak solutions the boiling point need not be reached4 ,for strong solutions the heating should be done under pressure so as to bring up the pressure to one to three atmospheres4 ,such solutions may contain as much as eight per cent4 of the gum4 ,the mixture is liable to coagulate or gelatinize just at the wrong time1 but it may be of value as a vehicle or as a waterproofing agent4 ,it deserves further investigation1 which it is to be hoped it will duly receive4 ,great care is necessary in working with naptha1 benzole1 carbon disulphide and similar liquids4 ,their vapor is given off at ordinary temperatures and may travel some distance to a lamp or fire and become ignited and carry the flame back to the vessel4 ,their vapors are also ansthetic and should be avoided as regards inhalation4 ,,chapter ,,xiii4 ,,ebonite1 ,,vulcanite ,,and ,,gutta-,,percha4 ,ebonite and ,vulcanite4--,these two well known substances are india rubber1 in which the vulcanization process has been intensified4 ,from twenty-five to fifty per cent4 of sulphur is added in the mixing1 and the curing is prolonged to several hours4 ,a temperature of #bge ,f4 7#ace ,c47 for six to ten hours is sometimes recommended1 but generally a shorter period at the regular temperature1 #bhd ,f4 7#adj ,c471 may be employed4 ,the mixed sheet is made and sold extensively for dentists' use4 ,it is soft and flexible and very easily moulded4 ,it is treated like the regular mixed sheet in every respect1 except that plumbago brushed on the slightly oiled surface of the mould is recommended instead of the light colored talc1 to prevent adherence4 ,wax where available is better than oil4 ,sometimes specimens are built up in sections4 ,about an hour before full vulcanization in the fourth stage1 new material can be added and will attach itself to the old4 ,the stages of vulcanization are thus given by ,bolas4 8,several distinct stages or steps may be traced during the curing of ebonite2 and ,i wish to call your attention to some specimens illustrating these various stages4 8,here1 in the first place1 is the plain mixture of sulphur and rubber1 this being nearly white1 and capable of becoming quite plastic or soft by the application of a gentle heat4 8,the second specimen illustrates the action of a very moderate degree of heat on the mixed material1 this particular sample having been heated to #abh ,centigrade for twenty minutes4 ,it is1 as you see1 somewhat darkened1 and has lost a little of its original softness2 while a degree of heat which would have rendered the original mixture plastic1 like putty1 fails to make much impression upon it4 8,the third specimen illustrates the effect of a more prolonged heating1 this sample having been heated for an hour to #ace ,centigrade4 ,it is olive green in color1 and has acquired a certain amount of elasticity1 resembling that of a rather inferior quality of vulcanized caoutchouc4 8,the fourth stage of curing is illustrated by this specimen1 which you see is brown1 and tolerably hard4 ,ebonite in this state refuses altogether to become plastic by heat1 and a temperature of #aej maintained for half an hour or less would suffice to bring it to the fifth stage1 or that of finished ebonite4 8,the fifth stage1 or that of properly cured ebonite1 is the goal to be arrived at in manufacturing the material4 ,there should be no places where the curing is imperfect1 a kind of defect which is likely to happen when articles of unusual thickness are vulcanized1 and no portion of the ebonite should be spongy or honeycombed by air bubbles4 8,the sixth1 or spongy state1 is generally the result of over-heating1 bubbles of gas forming in the material1 and converting it into a kind of porous1 cinder-like mass4 8,a specimen will now be handed round1 which illustrates the third1 fourth1 fifth and sixth stages1 as already described4 ,the specimen in question was cured on a hot plate1 this having probably been heated to #afj or #agj ,centigrade2 and you will be able to trace all gradations in the curing operation1 from the first setting of the plastic material to the destruction of the ebonite by overheating40 ,cement for uniting pieces of the partially cured material may be made by rubbing up some of the untreated scrap with benzole4 ,at the heat of boiling water1 ebonite can be bent to a certain extent1 which bend it retains on cooling4 ,when warm an impression of a coin or relief die may be made on it by heavy pressure which it will retain4 ,on heating the image disappears4 ,if before heating the surface is planed off and the piece is heated the image formerly in intaglio will expand into relief4 ,by the exact process of rubber stamp making excellent stereotype plates may be made of ebonite4 ,it can be turned at high speed in a lathe and polished with fine #jjj emery paper followed by a cloth bob with rotten stone1 etc41 and water or oil4 ,blotting paper1 charged with the above or with tripoli1 is excellent for polishing small surfaces by hand4 ,ebonite is a good connecting material between softer rubber and iron1 the whole being vulcanized together2 the iron should be well roughened or cut into rasp-like or file-like projections4 ,ebonite is properly the name for black hard rubber1 and vulcanite for the colored products such as used by dentists and others4 ,,gutta-,,percha4 ,gutta-percha is prepared by coagulation from the juice or sap of several trees1 among others the ,isonandra gutta1 of ,borneo and the ,east ,indian ,archipelago4 ,the product gutta-percha is identical in composition with india rubber4 ,it is hard at all ordinary temperatures4 ,its manufacture includes purification and mastication4 ,it is far more amenable to treatment than is india rubber4 ,many materials are mixed with it as adulterants or otherwise in the factories4 ,it is more useful in the form of sheets4 ,these when heated to #abb ,f4 7#ej ,c47 become pliable and can be moulded by pressure to any degree4 ,at the temperature of boiling water it becomes pasty and adhesive1 and at #bff ,f4 7#acj ,c47 it is so soft that it may be considered as melted4 ,it is an admirable moulding material4 ,stereotypes and other relief or intaglio images can be made by pressing it while heated4 ,these are often absolutely perfect reproductions of the original4 ,dishes for photographic purposes1 etc41 are easily made out of the sheet4 ,by gentle warming they become pliable1 and a greater heat makes surfaces capable of adhering by pressure4 ,tubes can be made by the squirting process1 as used for india rubber4 ,wires are coated with it in a similar manner4 ,it has several defects4 ,it is not durable if exposed to the air with consequent changes of temperature4 ,it is also too easily softened by heat1 as of course no hot liquid can be introduced into a gutta-percha vessel4 ,the ,parkes cold curing process can be applied to it1 which makes it more indifferent to heat4 ,this is applied by dipping an instant and drying4 ,after several repetitions the period of dipping is prolonged and ultimately it is left immersed some time4 ,if left immersed at first it would dissolve4 ,it is soluble in most caoutchouc solvents1 particularly in carbon disulphide4 ,,chapter ,,xiv4 ,,glue ,,or ,,composition ,,stamps4 ,stamps made from a mixture of glue1 glycerine1 and molasses or from similar mixtures are an excellent substitute for india rubber stamps4 ,properly made they possess all the flexibility that characterizes the rubber ones1 while for fatty inks such as that used by printers and lithographers1 which inks tend to destroy rubber stamps1 they are much better4 ,they are adopted by the ,united ,states government for making dating stamps for use in the ,post ,office ,department2 by publishers of directories for printing advertisements on the edges of their publications1 and in many other cases4 ,our description shall follow as closely as possible the process and methods used in the ,united ,states ,post ,office4 ,they are there termed 8composition blotters40 ,the composition of which they are made is printer's roller material4 ,nine and one-half pounds of fine quality glue are soaked in just enough soft water to cover it until it is thoroughly softened4 ,it is then melted4 ,in the ,government ,department a steam kettle is provided for the purpose4 ,an ordinary glue pot will answer for smaller quantities4 ,when melted four and one-half pounds of best molasses and seven pounds of glycerine are added1 and the whole is thoroughly mixed4 ,the formula varies a little according to the prevailing temperature1 less molasses being added when the weather is warm1 and vice versa4 ,experience is here the best teacher4 ,when well mixed it is poured out into tin pails whose inner walls or sides and bottom have been rubbed over with oil4 ,it solidifies in cooling and becomes a clear brown jelly quite free from any stickiness or superficial moistness4 ,illustration3 ,,model ,,for ,,composition ,,stamp ,,mould4 ,in use it is turned out of the pails to which1 owing to the oiling1 it does not adhere4 ,it is cut off as wanted1 melted by heat and cast in oiled moulds4 ,the latter are made of type metal to which one-third its weight of lead has been added4 ,as model for the mould or matrix a brass model of the stamp is employed4 ,this represents a sort of oval based cut-off or truncated cone1 about an inch high and a little over an inch long on its base4 ,a flange extends outward from its base and a tube is provided to fit this flange4 ,its smaller end corresponds to the face of the stamp1 and on it are engraved in full relief any permanent characters1 circles or border lines1 etc4 ,through its centre one or more apertures are made4 ,into these1 changeable steel1 iron or brass type may be introduced and set fast with plaster of paris4 ,illustration3 ,,composition ,,stamp ,,mould4 ,to make the mould1 the brass model with its movable type set as required is placed upon a flat table or plate1 face upward1 and surrounded by the tube1 as shown in partial section in the cut1 page #aad4 ,the tube is a strip of sheet iron1 which is bent around the flange and is secured in place by a wire twisted around it4 ,the melted alloy 7type1 metal and lead7 is poured into the space thus formed until it rises a quarter of an inch above the face of the model4 ,in a few minutes it sets and is removed and allowed to cool4 ,this gives a cup with the inscription and design depressed or in intaglio upon its inside base4 ,this is shown in the cut1 page #aae1 partly in section2 it will of course be understood that the mould forms a complete cup4 ,to make the stamp the interior surface of the mould is oiled with a stiff brush4 ,it is not material what oil is used4 ,the composition melted by heat is then poured into the cup1 and is allowed to solidify4 ,owing to the conical shape of the mould it is readily removed4 ,the mould must be hot but not too much so4 ,in the ,post ,office stamps the date requires to be changed frequently4 ,some of the figures do duty for two or three days each month4 ,thus the figure #h is in the designation of three days1 the eighth1 eighteenth1 and twenty-eighth4 ,there are three changes involved therefore in connection with this day numeral4 ,when a stamp mould or matrix is cast the place of numerals that are to be changed is filled with a blank space in the part where the type would otherwise come4 ,a number is stamped in this space when needed1 by means of an ordinary steel number-punch4 ,when the number is to be changed the old character is scraped or cut out1 leaving a small irregular hollow4 ,a very small piece of soft lead1 about one-sixteenth of an inch on each side1 is dropped into the hollow4 ,with a flat faced punch it is flattened out1 and on it the new number is impressed by a steel punch4 ,this operation is repeated a great many times before the matrix is worn out4 ,illustration3 ,,open ,,shut ,,composition ,,stamp ,,handle4 ,in the cut1 page #aae1 one number is shown as stamped into the soft lead1 and at the other end of the stamp is a blank space ready for a number4 ,the casting of a stamp is so extremely simple that no attempt is made to use movable type1 as in permanent rubber dating stamps4 ,while it is obvious that these composition stamps could be attached directly to wooden handles1 a special style of handle1 shown in the cuts1 is employed by the ,post ,office4 ,a wooden handle carries at its end a brass base1 to which is pivotted a swinging piece that is perforated by a conical oval aperture a little larger than the small end of the stamp4 ,the edges of this aperture are slightly rounded4 ,it is swung around as shown in the first figure1 and the stamp1 previously moistened on its sides1 is forced in4 ,if the stamp is properly made it is surprising how much force may be used to insert it4 ,if the edges of the brass swinging piece are not rounded there is danger of the composition being cut4 ,the stamp in its brass frame is then swung back over the brass base1 where it is secured by a catch4 ,the stamp is now ready for use1 as shown in the second figure of the cut4 ,it is imperative that no aqueous or glycerine ink be employed for continuous work with such stamps4 ,common printers' ink is perfectly satisfactory1 and the work may be nearly or quite as good as that executed by an india rubber stamp4 ,the ,post ,office manufactures a pad for use with printers' ink into whose manufacture the same composition enters4 ,the ink retainer is a piece of fine felt1 one-quarter to one-half an inch thick4 ,this is placed in the bottom of a shallow steel mould1 where it enters for half its depth into a recess that it accurately fits4 ,the composition from old stamps1 melted up1 is then poured upon and around it1 the mould being previously oiled4 ,when it is full a piece of strong manilla paper1 of the area of the felt only1 is placed upon the bottom of the glue pad on its centre1 which as it lies in the mould is its uppermost part4 ,the paper adheres strongly as the glue hardens4 ,eventually it is turned out of the mould1 and a pad1 shown in the cut1 is produced4 ,the dotted lines show the limits of the felt pad4 ,the glue composition underlies1 surrounds and extends outwards from the felt portion4 ,it is found that the elasticity of the composition makes the pad much pleasanter for rapid stamping4 ,illustration3 ,,composition ,,ink ,,pad4 ,the above description gives the clew to making any stamp of this description4 ,the matrix may be of dental plaster1 or of oxychloride of zinc cement4 ,the mould may be built up of type of any kind4 ,the composition is so cheap that the stamp can be made quite thick4 ,this gives it a high degree of elasticity and adaptability to uneven surfaces4 ,it may be mounted by adherence upon a flat board or block1 provided1 if necessary1 with handles4 ,if the board or block is placed upon the composition while it is still warm and liquid1 as it solidifies the board and composition will adhere with great tenacity4 ,all moulds or surfaces to which it is desired that the melted composition shall not adhere must be oiled4 ,the moulds must not be cold or the composition will not enter the fine divisions4 ,if on the other hand they are too hot the mixture will adhere4 ,experience will teach the right conditions for success4 ,below are given other formul for roller composition4 ,the formula already given in this chapter is that used by the ,united ,states ,post ,office ,department4 ,i4 8,old ,home ,receipt30 ,glue #b lbs41 soaked over night1 to ,new ,orleans molasses #a gallon4 ,not durable1 but excellent while it lasts4 ,,ii4 ,glue #aj lbs41 molasses #b gal41 ,venice turpentine #b oz41 glycerine #ab oz42 mix as directed above4 ,,chapter ,,xv4 ,,the ,,hektograph4 ,for obtaining multiple copies of writing1 the apparatus called the ,hektograph or ,papyrograph has been extensively adopted4 ,in general terms it consists of a tray filled with a jelly like composition4 ,any imprint made upon the surface with aniline ink can be transferred to paper by simple pressure4 ,the tray filled with composition is called the tablet4 ,it is thus prepared4 ,the tray may be made of tin or even of pasteboard or paper1 and should be about one half an inch deep4 ,it may be of any size1 according to the work it is to do4 ,the composition is made from the best gelatine and glycerine4 ,one ounce by weight of gelatine is soaked over night in cold water1 and in the morning the water is poured off1 leaving the swelled gelatine4 ,six and one-half fluid ounces of glycerine are now heated to about #bjj ,f4 7#ic ,c47 on a water bath preferably1 and the gelatine is added thereto4 ,the heating is continued for several hours4 ,this operates to expel the water and to give a clear glycerine solution of gelatine4 ,the composition is then poured into the tray1 which must be perfectly level in order to obtain a surface nearly even with the edge4 ,it is then covered so as to keep off the dust4 ,the cover of course must not come in contact with the smooth surface4 ,in six hours it will be ready for use4 ,the original copy that is to be reproduced is made upon ordinary paper in aniline ink4 ,one formula for the ink reads as follows3 ,aniline violet or blue 7#b ,r ,b or #c ,b7 #a oz41 hot water #g fluid oz42 dissolve4 ,after cooling add alcohol #a fluid oz4 and glycerine fluid oz41 a few drops of ether and a drop of carbolic acid4 ,keep in a corked bottle4 ,other formul are given in chapter ,,xvii4 ,the writing is executed with an ordinary steel pen4 ,the lines should be rather heavy so as to show a greenish color by reflected light4 ,the surface of the pad is slightly moistened with a wet sponge and is allowed to become nearly dry4 ,the paper is then laid upon it and smoothed down4 ,this is best done by placing a second sheet over it and rubbing this with the hand4 ,no air bubbles must remain between the copy and the tablet1 and the paper must not be shifted4 ,it is allowed to remain for a minute or less and is then raised by one corner and stripped from the gelatine surface4 ,it will have left the reversed copy of its inscription perfectly reproduced upon the tablet4 ,at once a piece of ordinary writing paper of the desired size and quality is laid upon the tablet1 smoothed down1 and stripped off1 when it will be found to have taken with it a complete copy of the inscription or writing4 ,this is repeated over and over again with another sheet of paper1 until the ink on the pad is exhausted4 ,fifty or more good copies can be thus obtained4 ,illustration3 ,,the ,,hektograph4 ,as soon as the work is completed the remains of the ink should be washed off with a moist sponge and the tablet1 after drying a little1 will be ready for a second operation4 ,some practice is required to ascertain the proper strength of the writing and degree of wetness of the surface4 ,when the gelatine surface becomes impaired it can be remelted in a water bath if it is not too dark from absorption of ink4 ,french ,ministry of ,public ,work ,formula4--,glue #ajj parts1 glycerine #ejj parts1 finally powdered kaolin or barium sulphate #be parts1 water #cge parts4 ,use a little hydrochloric acid in the water for washing off the pad after use4 ,hektograph ,sheets4--,four parts of glue are soaked in five parts of water and three parts of ammonia until soft4 ,it is then heated and there is added to it three parts of sugar and eight parts of glycerine4 ,the mixture is applied to blotting paper4 ,this is saturated with it1 and successive coats added until a smooth surface is produced on one side4 ,this is the side for reproduction4 ,it is used like the regular tablet except that it is claimed that sponging off the writing is not necessary4 ,owing to the capillary action developed by the blotting paper it is supposed to be self-cleaning by standing4 ,,chapter ,,xvi4 ,,cements4 ,before cementing vulcanized rubber the surface should be roughened or still better it may be seared with a red hot iron4 ,for bicycle tyres this is especially to be recommended4 ,cement for ,cuts in ,bicycle ,tyres1 ,rubber ,belts1 etc4--,carbon bisulphide1 #e ounces2 gutta-percha1 #e ounces2 caoutchouc1 #aj ounces2 fish glue1 #b ounces4 ,after it is applied and has dried the excess can be removed with a wet knife4 ,bad cuts should first be stitched up4 ,bicycle ,tyre ,cement to fasten ,tyres to ,rims4--,equal parts of pitch and gutta-percha are melted together4 ,sometimes two parts of pitch are prescribed4 ,this cement has extended application4 ,cement for ,paper ,boats and for ,mending ,rubber ,goods4--,fuse together equal parts of pitch and gutta-percha1 and to this add about #b parts of linseed oil containing #e parts of litharge4 ,continue the heat until the ingredients are uniformly commingled4 ,apply warm4 ,waterproof ,cement4--,shellac1 #d oz2 borax1 #a oz2 boil in a little water until dissolved1 and concentrate by heat to a paste4 ,another4--#aj parts of carbon disulphide and one part of oil of turpentine are mixed1 and as much gutta-percha is added as will readily dissolve4 ,cement for ,mending ,hard ,rubber4--,fuse together equal parts of gutta-percha and genuine asphaltum2 apply hot to the joint1 closing the latter immediately with pressure4 ,glue to ,fasten ,leather1 etc41 to ,metals4--#a part crushed nut galls digested #f hours with #h parts distilled water and strained4 ,glue is macerated in its own weight of water for #bd hours1 and then dissolved4 ,the warm infusion of nutgalls is spread on the leather2 the glue solution upon the roughened surface of the warm metal2 the moist leather is then pressed upon it and dried4 ,marine ,glue1 ,various ,formul4--,i4 ,dissolve #a part of india rubber in #ab parts of benzole1 and to the solution add #bj parts of powdered shellac1 heating the mixture cautiously over a fire4 ,there is great danger of conflagration4 ,apply with a brush4 ,,ii4 ,caoutchouc1 #a oz2 genuine asphaltum1 #b oz2 benzole or naptha1 q4 s4 ,the caoutchouc is first dissolved 7as described in chapter ,,xii471 and the asphaltum is gradually added4 ,the solution should have about the consistency of molasses4 ,cement for ,vulcanized ,india ,rubber4--,stockholm pitch1 #c parts2 ,american resin1 #c parts2 unmixed india rubber1 #f parts2 oil of turpentine1 #ab parts4 ,heat and mix very thoroughly4 ,more oil of turpentine may be added as required4 ,gutta-,percha ,cement for ,leather4--,soak gutta-percha in boiling water4 ,soften in benzole after cutting up for a day4 ,heat on a water bath until the greater part of the benzole is expelled4 ,when cool it will solidify4 ,use by heating4 ,cement for ,rubber ,shoes4-- 7#a7 ,chloroform #bhj parts4 ,india rubber 7masticated7 #aj 0 7#b7 ,india rubber #aj 0 ,resin #d 0 ,venice turpentine #b 0 ,oil of turpentine #dj 0 ,for first solution dissolve by mastication4 ,for second1 melt the finely divided gum with the resin1 add the ,venice turpentine and finally the oil of turpentine4 ,use heat if necessary4 ,mix both solutions finally4 ,to apply1 saturate a piece of linen with the cement and apply to the spot previously coated with the cement4 ,as it dries apply a little more as required4 ,a finishing varnish is given in the last chapter4 ,parkes' cold curing process may be applied as described in chapter ,,xi4 ,chatterton's ,compound for uniting sheets of gutta-percha in cable cores and for general work with gutta-percha coated wires4--,stockholm tar1 #a part2 resin1 #a part2 gutta-percha1 #b parts4 ,waterproofing for ,wooden ,battery ,cells4--,resin1 #d parts2 gutta-percha1 #a part2 boiled oil1 a little4 ,another ,formula4--,burgundy pitch1 #aej parts2 old gutta-percha in fine shreds1 #be parts2 ground pumice stone1 #ge parts4 ,melt the gutta-percha and mix with the pumice stone and then add the pitch1 melting all together4 ,apply melted and smooth off with a hot iron4 ,cement for ,celluloid4--,shellac1 #a part is dissolved in spirits of camphor #a part1 with #c to #d parts strong alcohol4 ,it is applied warm and the parts united must not be disturbed until the cement is hard4 ,,chapter ,,xvii4 ,,inks4 ,,rubber ,,stamp ,,ink4 ,aniline blue soluble1 #a ,b #c parts4 ,distilled water #aj 0 ,acetic acid #aj 0 ,alcohol #aj 0 ,glycerine #gj 0 ,for other colors the following aniline colors may be substituted in proportions given3 ,methyl violet1 #c ,b 7violet7 #c parts4 ,diamond fuchsin ,i1 7red7 #b 0 ,methyl green yellowish #d 0 ,vesuvin1 ,b 7brown7 #e 0 ,nigrosin1 ,w 7blue black7 #d 0 ,for very bright red #c parts of ,eosin ,,bbn4 are used4 ,in this case the acetic acid must be omitted4 ,in all cases the colors should first be rubbed up with the water in a mortar1 and the glycerine should be added gradually4 ,these inks will answer for the hektograph4 ,hektograph ,ink4--,aniline color1 #a part2 water1 #g parts2 glycerine1 #a part4 ,a little alcohol may be used with advantage to dissolve the aniline color4 ,it can be expelled by heating if it proves objectionable4 ,aniline ,ink ,vehicle4--,prof4 ,e4 ,b4 ,shuttleworth1 of ,toronto1 ,ont41 suggests the use of castor oil in place of vaseline and other vehicles for typewriter ink4 ,the aniline colors may first be dissolved in alcohol1 and the solution may be added to the oil4 ,they may also be dissolved directly in the oil in which most of them are soluble4 ,indelible ,stamping ,inks4--,i4 ,asphaltum1 #a part2 oil of turpentine1 #d parts2 dissolve and temper with printer's ink4 ,the ink may be omitted1 and solid dry color added4 ,,ii4 ,sodium carbonate1 #bb parts2 glycerine1 #he parts2 dissolve and rub up in a mortar with gum arabic1 #bj parts4 ,in a separate vessel dissolve silver nitrate1 #aa parts2 in officinal aqua ammonia1 #bj parts4 ,mix the two solutions1 and heat to the boiling point1 #bab ,f4 7#ajj ,c474 ,after it darkens1 add ,venice turpentine1 #aj parts4 ,after applying to the cloth1 a hot iron should be applied1 or it should be exposed to the sun4 ,,iii4 ,dr4 ,w4 ,reissig's formula3 ,boiled linseed oil varnish #af parts4 ,finest lamp black #f 0 ,ferric chloride 7sesquichloride of iron7 #b to #e 0 ,dilute a little for use with varnish4 ,after this ink has been removed1 no matter how completely it can be detected by dipping the paper into a solution of ammonium sulphide4 ,,iv4 ,aniline black in crystals #a part4 ,alcohol #cj 0 ,glycerine #cj 0 ,dissolve in the alcohol1 and add the glycerine afterwards4 ,show ,card ,ink4-- ,pure asphaltum #af parts4 ,venice turpentine #ah 0 ,lamp-black #d 0 ,oil of turpentine #fd 0 ,dissolve the asphaltum in the turpentine1 and thoroughly mix4 ,stencil ,ink4--,shellac1 #b ounces2 borax1 #b ounces2 water1 #be ounces4 ,dissolve by heat if necessary1 first the borax alone1 and then adding the shellac4 ,to the clear solution add gum arabic1 #b ounces4 ,color with lamp-black1 with ,venetian red1 or with ultramarine1 to suit the taste4 ,another formula gives shellac1 #d parts1 borax1 #a part1 and omits the gum arabic4 ,copying ,ink 7for use without a press by simply pressing and rubbing with the hand71 by ,prof4 ,attfield1 ,f4,r4,s4--,use ink of any kind of extra strength4 ,this in many cases can be made by evaporating common ink down to six tenths of its volume4 ,then mix with it two thirds of its volume of glycerine1 so as to restore the original volume4 ,white ,ink4--,barium sulphate1 or 8flake white0 is mixed with gum arabic water of sufficient thickness to keep it suspended1 at least while in use4 ,starch or magnesium carbonate or other white powder may be used instead of the barium sulphate4 ,the powder must be of impalpable fineness4 ,white ,ink on ,blue ,paper4--,a solution of oxalic acid in water is used for this purpose4 ,it may be applied with a rubber stamp or with a common pen4 ,a quill or gold pen is the best as a steel pen is soon corroded4 ,the ink bleaches the paper wherever it touches it1 giving white lines on a blue ground4 ,gold ,ink4--,gold leaf with honey is ground up in a mortar1 best an agate mortar1 or on a painters' slab with a muller4 ,it is added to water1 and thoroughly mixed and at once poured off from the first sediments1 filtered out1 and washed4 ,this is done to secure the impalpably finely ground gold only4 ,the resulting powder is mixed with a suitable vehicle1 such as white varnish or gum arabic water4 ,silver ,ink4--,as above1 using silver leaf4 ,zinc ,label ,ink4--,i4 ,verdigris1 #a part2 ammonium chloride1 #a part2 lamp-black1 part2 water1 #aj parts4 ,,ii4 ,platinum bichloride1 #a part2 gum arabic1 #a part2 water1 #aj parts4 ,diamond ,ink for ,etching ,glass4--,this consists essentially of hydrofluoric acid mixed with barium sulphate to the consistency of cream4 ,the barium sulphate is quite inoperative except as giving a body to prevent the ink from spreading4 ,it is applied with a rubber stamp or pen and allowed to remain for ten minutes or until dry4 ,on removal of the white powder1 the design will be found etched on the glass4 ,the following is a formula for it4 ,saturate hydrofluoric acid with ammonia1 add an equal volume of hydrofluoric acid and thicken with barium sulphate in fine powder4 ,,chapter ,,xviii4 ,,miscellaneous4 ,to ,soften and ,restore ,india ,rubber ,hose1 etc4--,i4 ,dip in petroleum and hang up for a couple of days4 ,repeat process if necessary4 ,,ii4 ,the above process is applicable to all articles1 but is specified for hose4 ,it is stated that old rubber that has become hard may be softened by exposure first to vapor of carbon disulphide1 followed by exposure to the vapor of kerosene4 ,the latter vapor is found to be a general preservative for india rubber4 ,,iii4 ,dr4 ,pol recommends immersion in a solution of water of ammonia1 #a part1 and water #b parts1 from a few minutes to an hour4 ,to ,prevent ,decay of ,rubber ,tubing4--,the decay of rubber tubing has been attributed to the formation of sulphuric acid from the sulphur mixed with it4 ,m4 ,ballard has suggested washing with water or weak alkaline solution five or six times in a year4 ,joints between ,india ,rubber ,tubing and ,metal4--,where tubing is temporarily slipped over metal gas pipes and similar connections1 as in the chemical laboratory1 it is well to apply glycerine to the metal4 ,it acts as a lubricant in slipping the tubing on1 and assists in its withdrawal4 ,preserving ,vulcanite4--,wash occasionally with a solution of ammonia and rub with a rag slightly moistened with kerosene oil4 ,effect of ,copper upon ,rubber4--,in a paper read before the recent meeting of the ,british ,association1 ,sir ,william ,thomson stated that metallic copper1 when heated to the temperature of boiling water1 in contact with the rubber1 exerted a destructive effect upon it4 ,with a view to finding whether this was due to the copper per se1 or to its power of conducting heat more rapidly to the rubber1 he laid a sheet of rubber on a plate of glass1 and on it placed four clean disks1 one of copper1 one of platinum1 one of zinc and one of silver4 ,after a few days in an incubator at #aej ,f41 the rubber under the copper had become quite hard1 that under the platinum had become slightly affected and hardened at different parts1 while the rubber under the silver and under the zinc was quite hard and elastic4 ,this would warrant the inference that the metallic copper had exerted a great oxidizing effect on the rubber1 the platinum had exerted a slight effect1 while the zinc and silver respectively had no injurious influence on it4 ,the rubber thus hardened by the copper contained1 strange enough1 no appreciable trace of copper2 the copper1 therefore1 presumably sets up the oxidizing action in the rubber without itself permeating it4 ,gas ,tight ,tubings4--,fletcher has invented a gas tight rubber tubing in which a layer of tinfoil is interposed between two concentric rubber tubes1 all vulcanized together4 ,printing ,colors upon ,india ,rubber4--,it may sometimes be desirable to have a surface of vulcanized india rubber so prepared that it will take colors such as are used for calico printing4 ,this end is simply attained by sprinkling the article with farina before vulcanizing4 ,a small quantity attaches itself and forms an excellent base for color printing4 ,gutta-,percha for ,coating ,glass4--,for focusing glass in photography and for similar purposes where ground glass or a translucent material is required1 a solution of gutta-percha in chloroform is highly recommended4 ,this is flowed over or painted on the glass and is allowed to evaporate afterwards4 ,burned ,rubber4--,a very soft pure gum sold for artists' use is improperly termed burned rubber4 ,it is used in crayon work for removing and lightening marks by dabbing it against the paper1 cleaning the rubber from time to time4 ,it is so soft that it picks up and removes crayon marks without the necessity of friction4 ,thus the rubbing out or more properly erasing operation can be localized and crayon tints can be lightened in tone without impairment or 8smutting40 ,it is a very elegant accessory to the artists' paraphernalia4 ,to make it1 pure virgin gum1 preferably the best ,para1 is cut into pieces and soaked for some hours in benzole4 ,a long soaking is advisable4 ,the pieces are then removed from the benzole and are ground in a mortar until perfectly homogeneous4 ,the mass is gathered up with a spatula and is pressed into little tin boxes4 ,if desired it may be dried upon a water bath4 ,this is not necessary as1 if the box is left open1 it will rapidly season itself4 ,it should be very soft1 should tend to adhere to the fingers1 yet should leave them easily1 and should strip cleanly from the box4 ,a very little turpentine makes it more adhesive4 ,it may even be softened in turpentine alone4 ,this gives a gum that seasons more slowly and is in some respects preferable to the benzole made preparation4 ,it is sold at a high price by the dealers1 as the demand for it is limited4 ,rubber ,sponge4--,this is also an artist's rubber4 ,it is also used for cleaning kid gloves4 ,it is made by incorporating with the masticated or washed and sheeted gum any material or materials that will give off vapor in the curing process4 ,damp sawdust and crystallized alum are used as giving off vapor of water or steam1 or ammonium carbonate as giving off vapors of ammonia carbonic acid gas and steam4 ,the mixed gum may be cured in moulds1 which it will fill by its expansion4 ,shellac ,varnish for ,india ,rubber4--,this is made by soaking powdered shellac in ten times its weight of strong aqua ammonia 7#bf ,b474 ,at first no change beyond a coloring of the solution is perceptible4 ,after many days standing the bottle1 which should have a glass stopper1 being tightly closed1 the shellac disappears1 having entered into solution4 ,it may be a month before complete solution4 ,this forms an excellent varnish for india rubber shoes and similar articles4 ,it may be applied with a rag4 ,it is also a good application for leather in some cases and doubtless many other uses could be made of it4 ,it would act well as a vehicle for a dark pigment such as lamp-black4 ,it will rejuvenate a pair of india rubbers very nicely4 ,the ammonia exercises also a good influence on the rubber4 ,it has been recommended as a cement for attaching rubber to metal1 but its adhesive powers are not always satisfactory4 ,simple ,substitute for ,stamps4--,a very simple though rough and imperfect substitute may be made by gluing with common carpenter's glue pieces of thick string upon a piece of wood1 the string being given the form of the desired letters4 ,care must be taken to avoid saturating and stiffening the string with the glue4 ,india ,rubber ,substitutes4--,one of these under the name of vulcanized oil is thus described by ,bolas3 8,vulcanized oil is1 perhaps1 of more interest1 and many oils1 such as linseed and others resembling it1 may be vulcanized by being heated for some time to #aej ,centigrade with twelve to twenty per cent4 of sulphur4 ,the product obtained is soft1 and somewhat resembles very bad india rubber4 ,by increasing the proportion of sulphur very much indeed1 say to four times the weight of the oil1 and vulcanizing at a higher temperature1 a hard substance1 resembling inferior vulcanite1 is obtained4 8,soft and hard vulcanized oil have been introduced into commerce at various times and under many names2 but these materials never seem to have made very much headway40 ,another method of treating the oil consists in mixing it with a solution of chloride of sulphur in carbon disulphide or in naptha4 ,on standing1 the volatile solvents escape1 leaving a thick mass1 which is the substitute4 ,in combinations of aluminum with the fatty acids1 forming aluminum soaps1 and of these1 aluminum palmitate especially1 a substitute for india rubber has been sought but without success4 ,metallized ,caoutchouc4--,unvulcanized gum is mixed with powdered lead1 zinc1 or antimony4 ,the mixed india rubber is then cured as in the regular process4 ,,emery ,,wheels ,,and ,,whetstones4 ,bolas thus describes their manufacture3 8,when ordinary vulcanized rubber is heated to #bcj ,centigrade1 7#ddf ,f47 or until it melts1 a permanently viscous product is obtained1 and this substance1 if mixed with emery and sulphur to a kind of paste1 forms a material out of which the so-called agglomerated emery wheels or grinders may be formed1 the mixed materials being next hardened or cured by the application of a steam heat4 ,emery wheels and hones made on this principle were introduced by ,deplanque about twenty-three years ago4 8,thirty-five parts of old vulcanized caoutchouc having been placed in a kind of still1 heat is applied to melt it1 the operation being assisted by the gradual addition of about ten parts of heavy coal oil2 but this latter is afterward distilled off4 ,the softened caoutchouc is then incorporated with #ejj parts of emery of the required degree of fineness and nine parts of sulphur4 ,these materials having been thoroughly mixed1 the hones or wheels are manufactured1 and afterward cured or baked at a heat of #adj ,centigrade1 7#bhd ,f47 during a period of about eight hours4 ,grinding wheels1 made in the above manner1 can be worked at a speed of #b1jjj revolutions per minute1 and are extremely useful for the working of hardened steel or other obdurate materials40 ,etching on ,metals and ,glass4--,india rubber stamps can be used for placing the ground upon knife blades and similar articles which are to be etched4 ,the parts untouched by the stamp are attacked by the acid4 ,in the case of glass1 diamond ink 7page #acc7 can be put on with a stamp4 ,the acids for metal etching might be thickened with barium sulphate also and applied in the same way4 ,in these cases the inscription of the stamp would be etched4 ,where ground is put on1 whether on glass or metal1 the design for the stamp will be protected4 ,etching ,ground for ,metals4--,equal parts of asphalt1 ,burgundy pitch and beeswax melted together and mixed thoroughly4 ,it may be softened with mutton suet4 ,beeswax may be used1 dissolved in ether or simply melted4 ,yellow soap is sufficient for ordinary work4 ,etching ,solutions for ,biting in4--,for steel and iron1 a4 sulphate of copper and common salt in solution4 b4 sulphate of copper1 sulphate of alumina1 and common salt1 of each two drachms2 acetic acid1 #a oz4 c4 sulphuric acid1 diluted with five volumes of water with a little sulphate of copper4 ,for other metals1 except gold and platinum1 nitric acid diluted with five volumes of water4 ,etching ,ground for ,glass4--,melted beeswax is generally recommended4 ,it can be removed with spirits of turpentine after as much as possible has been scraped off4 ,etching ,glass4--,glass may be conveniently etched by exposing it to the vapor of hydrofluoric acid4 ,a shallow leaden tray1 as large as the glass1 is required4 ,a quantity of fluorspar is placed in it and is moistened with concentrated sulphuric acid4 ,the glass is placed face downward over the tray4 ,it is supported over the mixture by resting on the edges of the tray or by any simple method1 and the whole is covered with a towel4 ,in half an hour or more the etching will be completed4 ,the vapors must not be allowed to escape into any room containing glass or metal articles as they corrode everything4 ,great care should be taken also not to let the mixture touch the hand1 as painful ulcers are the result4 ,india ,rubber ,shoe ,blacking4--,raw india rubber is given as a constituent of several shoe blackings4 ,formul are given as below for paste and liquid blackings4 ,i4 ,paste blacking3 bone-black1 #bj parts2 molasses1 #ae parts2 vinegar1 #d parts2 sulphuric acid1 #d parts2 caoutchouc oil 7as given below71 #c parts4 ,,ii4 ,liquid blacking3 bone-black1 #fj parts2 molasses1 #de parts2 gum arabic dissolved in water1 #a part2 vinegar1 #ej parts2 sulphuric acid1 #bd parts2 caoutchouc oil1 #i parts4 ,caoutchouc oil is made by dissolving or digesting virgin rubber #ee parts in linseed oil #dej parts4 ,waterproof ,composition for ,boots4--,one ounce of virgin rubber cut into pieces is digested in enough oil of turpentine to form a stiff paste4 ,in applying heat take great care lest the contents of the vessel become ignited4 ,when homogeneous1 which condition may be brought about by rubbing in a porcelain mortar1 as described in chapter ,,xii41 it is mixed with #e-f ounces of boiled linseed oil4 ,this gives an ointment almost of the consistency of butter4 ,,index4 ,,page ,absorption of sulphur process #ajj ,absorption of water by india rubber #ca ,africa1 ways of collecting rubber sap #ae-ag ,analysis of sap of india rubber tree #bg ,apparatus for stamp making #fa-fc ,artists' burned rubber #acf-acg ,balloons #ie ,bands1 india rubber #da ,bicycle tyre cement #abe ,blacking1 india rubber #adb ,borax and water solution of rubber #ajf-ajg ,brazil1 ways of collecting sap #bj-ba ,bromine as vulcanizer #ajj ,bulbs1 how made #ib-ic ,burned rubber1 artists' #acf-acg ,calendering #dc ,cane tips #ij ,caoutchin #cj ,caoutchoucin #cj ,caoutchouc1 7see ,india ,rubber47 ,cements #abe-abh ,clamp for vulcanizing press #eb ,cohesion of rubber1 its importance to the manufacturer #bf-bg ,cold curing #ajj-ajb ,composition for stamps and its moulding #aac-abj ,composition inking pad #aah-aai ,composition stamp handle #aag-aah ,cord1 rubber #ib ,corks #ij-ia ,curing #dd ,curing1 how to judge of completion of #gj ,curing in liquid bath #ig ,curing in sulphur bath #ii ,curing1 temperature of #eh ,central ,america1 ways of collecting rubber #ah-ai ,chair leg tips #ij ,chalk plates #hc-hd ,chlorine as vulcanizer #ajj ,chloroform as a solvent #aje ,coagulation of sap by a plant #ai ,coagulation of sap by alum #bb-bc ,coagulation of sap by fire #ba-bb ,coagulation of sap by salt #ah ,cohesion of pure rubber #be ,dating stamps1 composition #aaf-aag ,didot's polytype for matrices #hb-hc ,distillation products of india rubber #bi-cj ,dolls1 how made #ib-ic ,ebonite #ajh-aaa ,ebonite1 polishing #aaj-aaa ,emery wheels and whetstones #aci-adj ,emulsion of caoutchouc #aj ,etching #adj-adb ,fins1 removal of #hf ,flask for type moulding #gd ,flong matrices #hj-hb ,flong paste #hj ,fluid for mixing with plaster for matrices #ee ,gas heated steam vulcanizer #ec ,glue1 marine #abf ,glue stamps #aac-abj ,glycerine bath for curing #ig ,goodyear1 ,charles #ac-ad ,gutta-percha #aaa-aab ,gutta-percha1 moulding #aaa-aab ,gutta-percha1 vulcanizing #aaa ,hektograph1 composition #aba-abb1 #abd ,hektograph1 how made and used #aba-abd ,hektograph ink 7also see inks7 #aba ,hektograph sheets #abd ,india ,rubber1 absorption of water by #ca ,india rubber1 ,african #ae-ag ,india rubber1 artists' burned #acf-acg ,india rubber1 availability for small articles #he ,india rubber1 cohesion of unvulcanized #be ,india rubber1 composition of #bg ,india rubber1 discovery of1 etc4 #aa-ac ,india rubber1 effects of temperature on #bh-bi ,india rubber1 elasticity of #bi1 #cc ,india rubber sap1 its coagulation #aa ,india rubber sheet1 how made #dj ,india rubbers1 original way of making #aj ,india rubber stamp making without apparatus #ga ,india rubber stamps1 home-made mould #dh-ej ,india rubber stamps1 starting point #dg ,india rubber1 trees producing #i ,india rubber tree sap1 analysis of #bg ,india rubber type #gc ,india rubber1 vulcanized1 general properties of #cb-cc ,india rubber1 where collected #aa ,india rubber1 inelastic1 how made #ca ,india rubber1 its mastication #ch-dj ,india rubber1 manufacture of #ce-df ,india rubber1 necessity of drying #ch ,india rubber1 points to be followed in moulding small articles #he ,india rubber1 preliminary operations in manufacturing #ce-cf ,india rubber1 preserving1 etc4 #acd-ace ,india rubber1 properties of #bh ,india rubber sap #i-aa ,india rubber stamp vulcanizing #eh-fj ,inelastic state of india rubber #ca ,inks1 special for stamping1 etc4 #abi-acc ,iodine and haloid vulcanizers #ajj ,isoprene #cj ,leaves1 skeletonized as models #ib ,liquid bath curing #ig ,machine for cutting sheet and threads #dj ,machine for making mixed sheet #db-dc ,machine for masticating #ch-dj ,machine for washing and sheeting #cg ,mackintosh #ac ,mackintoshes1 how made #de-df ,marshmallow root for mixture with plaster #eg ,masticated rubber1 its easy solution #ajc-ajd ,masticating in mortar with benzole #ajc-ajd ,mastication of rubber #ch-dj ,materials mixed with india rubber #dc ,matrices1 various kinds of1 for stamps #hj-hd ,matrix for stamp-making #ed-ee ,matrix making by casting #ef-eg ,matrix press #ef ,matrix1 process of making1 for stamps #ed-ee ,mats #ia-ib ,metals1 welding and cohesion of #be-bf ,miscellaneous #acd-adb ,mixed sheet #db-dd ,mixed sheet for stamps #dg-dh ,mould1 home-made for stamps #dh-ej ,moulding and curing stamps #eh-fj ,moulds for composition stamps1 temperature of #abj ,moulds1 material for #hf ,naptha and volatile solvents1 danger of #ajg ,naptha1 solvent #ajd-aje ,nicaragua1 ways of collecting sap #ai-bj ,nitric acid as vulcanizer #ajj ,oil for composition stamp moulds #aai-abj ,oil for mould face #ee ,oils fixed bad effect on solutions #aje ,oxychloride of zinc cement for matrices #eg ,papier mach matrices #hj-hb ,paraffin and rubber #aje-ajf ,parkes' process #ajj-ajb ,payen's solvent #aje ,pencil tips1 moulds for #hi-ij ,phenyle sulphide as softener of vulcanized rubber #ajf ,plaster1 dental for matrices #ed ,press for moulding stamps1 etc4 #ea-eb ,press1 gas-heated #eb-ec ,press1 home-made #di ,press1 matrix making #ee-ef ,products1 general division of #ce-cf ,rods1 stirring for laboratory #ie ,rubber1 origin of name #ab ,rubber1 see ,india ,rubber ,salt bath for curing #ih ,sap of india rubber tree1 analysis of #bg ,sheeting and washing #cg-ch ,sheet rubber1 how made #dj ,sheet rubber1 its joining #id ,shellac for strengthening matrix #ee ,shoes1 blacking for #adb ,shoes1 india rubber1 cement for #abg ,siphonia1 origin of name #aa ,solution1 different views of #ca-cb ,solution1 difficulties of #ajc ,solvents for rubber #ajd-aje ,spring chase for matrices #ef ,springs for stamp moulds #ea ,springs on moulding press #ea ,sponge india rubber #acg ,stamp making #dg ,stamps1 rubber1 substitute for #ach ,stamps1 see ,india ,rubber1 ,composition and general titles4 ,strauss' method of coagulating sap #bb-bc ,suction discs1 regular mould for #hh-hi ,suction discs1 simple mould for #hg-hh ,sulphides1 alkaline as vulcanizers #ajj ,sulphur1 absorption process #ajj ,sulphur bath for mixing and curing #ih-ajj ,sulphur chloride process #ajj-ajb ,sulphur1 how mixed with gum #dc ,sulphur1 its escape from vulcanized rubber #cc-cd ,sunlight excluded from washed sheet rubber #ch ,syringes made by ,indians #aa ,test for curing with knife #dh ,thread1 rubber1 cut #da ,thread1 rubber1 moulded #ib ,tissues1 coated1 how made #de-df ,tubes1 connecting glass #if ,tube1 seamless #ib ,turpentine1 a solvent for vulcanized rubber #ajf ,turpentine compared with caoutchoucin #cj ,turpentine1 viscid nature of solution #ajd-aje ,type1 india rubber #gc ,type moulding flask #gd ,type and stamps from vulcanized rubber #gg ,type1 cutting apart #ge ,type1 points in moulding #ge ,type1 quads1 and spaces for stamp models #ga-gb ,type1 steel moulds for #gf ,united ,states composition stamps #aac-abj ,varnish shellac for india rubber #acg-ach ,vulcanite #ajh-aaa ,vulcanization1 its two steps #db ,vulcanization1 steps in process #dg-dh ,vulcanized rubber stamps and type #gg ,vulcanizer #eb-ec ,vulcanizer1 fish kettle as a #fi-gj ,vulcanizer1 flower pot #fh-gj ,vulcanizer1 chamber #fc ,vulcanizing and moulding stamps #eh-fj ,washing and sheeting #cg-ch ,water absorbed by india rubber #ca ,waterproof composition for shoes #adb ,waterproofing for battery cells #abg-abh ,zinc1 chloride #eg ,transcriber's ,notes ,punctuation1 hyphenation1 and spelling were made consistent when a predominant preference was found in the original book2 otherwise they were not changed4 ,simple typographical errors were corrected2 unbalanced quotation marks were remedied when the change was obvious1 and otherwise left unbalanced4 ,illustrations in this e,book have been positioned between paragraphs and outside quotations4 ,in versions of this e,book that support hyperlinks1 the page references in the ,list of ,illustrations lead to the corresponding illustrations4 ,the index was not checked for proper alphabetization or correct page references4 ,three missing page references were added by the ,transcriber4 ,page #bf3 8,the relegation of ice0 was printed that way4 ,page #dj3 8alkanine0 may be a misprint for alkaline4