SCIENTIFIC AMERICAN SUPPLEMENT, No. F'EBRTlARY 21, 18\H. 790. 12621
armor, are all combined and merge into each other in a not be ignored without very exhaustive trials, and I recently with the paper process alone, and, even by very ueat and compact manner, forming complete pro think it will become a matter of necessi ty before long. trespassing on your patience as much as was then the tectiOlI throughout. Hoping, sir, that you will be able to appreciate my case, some ten or fifteenlectures would be needed. 5th. The protective decks forward and abaft of the humble endeavors in trying to improve on old :Noah's The invention of the plaster mould process was turret" are intact without the usual Dumber of hatch ark (after our thousands of years of engineering pro spoken of in the firstlecture, and in spite of the com ways and openings cut through them, and give com gress), which still holds the day. parative slowness with which work is turned out, and plete protection, the only openings required being one the cumbrous nature of the appliances required, the in each for a coal chute, placed behind the turrets and plaster process survives, principally for casting from A MULTIPLE PORTRAIT. fit.ted with wa ter-tight covtlrs. formes of music type. In this case it is specially adapt 6th. The ends of the vessel above the protective deck WE have received from one of our readers, Mr. G. ed for the work, as so many of the music characters are built up to the required height, and intended only Paboudjian, of Constantinople, a curious photograph , hang over the body or shank of the type, and these as a superstructure t.o give the ship freeboard, to insure which we reproduce herewith, and which was taken by overhanging sorts would be very liable to injury in her good sea-going qualities. This superstructure be a process which is very simple, though not comprehen moulding by the paper process, also in the drying ing used only as coal bnnkers. where the coal will sible at first. We see the same subject represented a press; while the plaster mould has the advantage affol'd the most protection, and being above the water num bel' of times, and the whole presents the aspect of that imperfect joints in the lines of the music staff can liue, may be seriously damaged or uearly all shot away a number of persons standing in a line. In order to be made good by carefully drawing a piece of metal during action without materially affecting the safety obtain such a photograph, Mr. Paboudjian uses two rule along the lines in the mould. of the ship. mirrors, A and placed parallel and separated by an When a forille is set with the view of being stereotyp 7th. In steering and maneuvering qualities she will interval of aboutB, twenty-four inches. In this space, at ed by the plaster process, quadrats and spaces as high be superior to a single hull ship, having the centers of C, he places the subject to be photographed. Every as the shanks of the letters are often used, and, for the machinery much further apart. one knows the effect produced under such circum· convenience of stereotyping, music fonts are ordinarily 8th. In case of accident, disablement of machinery, stances, from having often observed it. In cafes, the furnished with high spaces and quadrats. or filling of one of the hulls, the other would be able shops of hair dressers, and in our own apartments Narrow clumps are generally placed so as only just to work independently and have sufficient buoyancy even, there are often two mirrors that face each othe'r, to surround the forme, and outside these we have the to float her. and in which we may daily observe the curious effect ordinary low furniture. '],he first thillg is to rub a 9th. In speed, as each hull has its own separate en of perspective in question. It is this effect that it is paste of plaster of Paris and water well into the iuter· gi ne power. the speed may be as great as that of any a questiou of fixing upon the photo�raphic plate, bllt stices of the forme, this being done with the hand, and other vessel of equal displacement and horse power. without the operator himself appeariug thereon with as the plaster sets, the excess is brushed away with a As this design combines the sea-going qualities of his apparatus. For this, as shown in the diagram, it stiffish brul;h, so as to leave the face of the type clear of cruisers with the low exposed side (of the hull proper) suffices that one of the mirrors shall be a little taller plaster, the depths of the forme partly filled in, and of monitors, it may be designated a "cruising than the other and that the apparatus, placed above the vertical sides of these depths sloped off with banks Inonitor. " the shorter oue, shall be slightly inclined toward the of plaster. In the application of this form of twin hull to pas It is desirable to allow this "fill ing in" to become senger ships and other vessels, some very important dry before further treatment, and warmth may be em advantages are obtained, among which are included ployed to expedite the drying, after which the face of greater comfort, safety and accommodation. First, the type is finally cleaned by the brush, and any frag the great bete nair of ocean travel-sea sickness-will ments of plaster which clog the faces of the letters 11Just he considerably modified. Magnificent cabin accom be picked out. The forme, being now clean alld dry, IllOdations can be obtained owing to the enlarged deck is thoroughly oiled. enough oil being used to satnrate room over the two hulls. Greater safety is assured against the surface of the filling in plaster, and although the los8 by collision with icebergs orother vessels, as it would type should be well oiled, the hollows on the face of be impossible for both hulls to be damaged at the same such letters as a or e should not be Ipft full of oil. The time; also in case of break-down or accident to the low priced thin mineral lubricatilJg' oil recolIlllJended in machinery, the whole ship would not become dis the case of the paper process is illconveniently thin. 80 abled. it is better to use such an oil as cotton seed oil or rape Regarding the docking of a vessel of such great seed (colza) oil. beam as this, although there are no graving docks Some strips of thin sheet metal are now laid on the capable of receiving her, slipways are now in exist furniture, outside the narrow clumps, * and an iroll ence on which she could be taken up easily. frame about three-quarters of an inch deep is laid The foregoing particulars are from the Inventive Age. over, so as to inclose the forme with its CIUlllPS, when Mr. A. J_ Purdy, of Washington, D. C., writes us as some plaster of Paris, mixed with water to the con follows: sistency of thick cream, is poured over the type, after For each hull, separate, the dimensions are as fol which a brush is worked with an up and down motion lows: in the plaster covering. so as to chase away air bubbles, Length of vessel between perpen- but this brush should not be drawn out of the plaster diculars __ ...... __ .... 280 ft. till the dabbing is finished. or fresh bubbles would be Breadth, moulded. _ ...... 39 ft. created. 'fhe frame is now filled with the mixed pIas Depth, moulded ...... _ 19 ft. 6 in. ter, and as it begins to set, the top is scraped off level Draught of water ...... 16 ft. 6 in. ' with a straight edge. All the plaster should be of the Displacement (each hull) ...... 3,500 tons. same mixing, as, if a stiffer plaster is used to fill up. Coal supply, but bunkers not there will probably be distortion in drying. Rathpr low filled. _ ...... _...... 600 tons. priced plaster is often to be preferred for this purpose than the very finestqua lity, which cOIJJmands its high She will have one set of triple expansion upright en price mainly on account of its whitenes8, freedom from gines in each hull of 3,000 indicated horse power, which dark specks, and the fil1eness with which it is ground. it is estimated will propel her at a speed of 14 knots It is of the utmost. importance that the plaster used per hour, with an endurance of 10 days' steaming with FIG. 1.-REPRODUCTION OF A PHOTOGRAPH should have been freshly roasted, and at such a heat out recoaling. as to set quickly and firmly. The stereotyper can Her armament will consist of eight 10 in. R. B. L. guns, OF A MULTIPLE PORTRAIT. easily judge of these points for himself. Extremely each having a range of 208 deg.; 4 rapid fire machine fine grinding is of no ad vantage. as the surface obtain guns mounted in the fighting tops on the mast heads, floor. It is necessary, too, to use mirrors without frames, ed is no better than with moderately fine grinding, and 6 rapid fire guns mounted on the hammock berth �ince the latter, on being reflected in the glass. would while flatter and better casts are obt.ained in the latter ing on deck, as protection against torpedo boat at produce a very bad effect.. The experiment llIay be case. As a rule, the plaster should be obtained direct tacks. This will constitute the whole of her arnla' complicated byem ploying three mirrors arranged in the from the maker, who will usually supply the smallest lIIent for coast and harbor defense, and will form one form of a prism, the reflecting surface being turned in quantities if sent for; and generally the grade sold in of, if not the most., formidable battery afloat. ward. Two or three persons placed in the interior gi ve London as "fine" is more suitable than ., superfine" The side armor will be 20 in. thick, turret 12 in., and the impression of a large crowd. In order to obtain It or "double superfine." In mixing the plaster, a quan protective decks 3 in. and 2 in. respectively; the main photograph of this kind, it is clear that it is necessary tityof water is taken in a basin, alld powdered pIas walls of the turrets being stationary, only t.he sloped to pose. The light is always inadequate for making an ter is added in a stream till it is judged that enough canopy revolving. instantaneous photograph, especially if it is desired has been added. Before proceeding to mix with a The cabin and officers' quarters are arranged on the to have the distances (which are less and less illumin spoon, it is well to see that the water has penetrated main deck amidships, from which easy access can be ated) as remote as possible. As for employing magne to the top of the blunt cone of the plast.er, which at attained to either end of the vessel. Seamen's quarters, si uIll. that appears to be difficult, since, on accouut of this stage will stand above the water level. In thil; llIess rooms, etc. , are all below the protective deck at the reflection upon the mirrors, there would be a dan cace it is easy to mix the plaster without forming many the ends, and afford large and commodious aCCOlIlIIlO ger of cloudiness. It would be curious, especially in air bubbles, which would not be the case if the water
© 1891 SCIENTIFIC AMERICAN. INC 12622 SCIENTIFIC AMERICAN SUPPLEMENT, No. 790. FEBRUARY 21, 1891.
cover is cut away at the corners so that the Illetal can letter-press matter containing engravings, and when probably require building up with wax, so that t,he freely flow in. This dipping pan is lowered into a pot the original wood is to be moulded from the electro electrotype shall have sufficient depth, and perhaps of melted type metal and kept there for ten or fifteen type, this method is perhaps the most desirable process the simplest way of doing this is to hold a pointed pen minutes, after which it is lifted out and cooled. The of stereotyping, as no moisture or heat is used in cil of iron or copper (building iron) in the right hand, plaster casts floats up against the lid of the dipping moulding; and in spite of what I said about the best and having warmed the metal rod, a slender stick of pan, while the floatingplate rests against the rim of possible stereotype by the paper method being equal wax is held against it, so that a slow and steady the plaster Illould, thus gauging the thickness of the to the best electrotype, the average commercial elec stream of melted wax flows from its point. A watch cast. trotype of the present day is very much better, as re ful person can soon learn to lead this stream to the re Little need be said about the trimming and finishing gards surface and definition, than the average com quired places, and can raise the wax close to the bor· of the cast except that, as the cast is not of an accu mercial stereotype by the paper process. ders of cavities in the mould, without fear of filling rately gauged thickness, and, moreover. as the floating If an electric current is passed through a solution of them. Several "building irons " of assorted sizes plate is rough-as there would obviously he no advan copper sulphate (bluestone or blue vitriol), so that the should be provided, and if a minute gas jet plays on tage in surfacing or planing it-it becomes essential current passes from one copper plate im mersed in the the tool, a little way from the tip, time will be saved; solution to another copper plate also immersed in the solution, one of these copper plates will become thicker from the deposition of copper, while the other plate becomes thinner by the dissolving away of just so much copper as was deposited upon the first. In this case, although the solution of sulphate of copper is doubtless decomposed and reformed during the action, FIG. 24.-THE DIPPING PAN. it is there at the end, and for our present purpose we may regard the change as a mere transference of to trim or plane the back of the plate, and this is gene copper from one plate to the other, the deposition tak rally done by a special surfacing lathe. Although pias ing place on that copper plate connected with the zinc ter expands at the moment of setting, it afterward plate of the electric battery, and the dissolving away contracts in drying, and a plaster stereotype is, there taking place in the case of that plate connected with fore, smaller than the original by about l-80th linear. the other pole of the battery, which may be a silver Gypsum, the mineral which, whHn gently roasted, plate, a platinum plate, or a carbon plate. This action gives plaster of Paris, may be regarded as a compound you can see going on before you, not only with a of sulphate of lime (calcium sui phate) and water in the battery, but also with two forms of dynamo machine proportions indicated by the formula: used as the source of the electric cnrrent, and if I re place one of those copper plates, upon which more Ca SO, . 2 H20 'metal is being deposited, by a wax mould of typo The above formula corresponds to about21 percent.of graphic matter well brushed over with black lead, water in the mineral, but when the gypsum is exposed the cop er is deposited on this mould, and in time to a heat ranging from 1200 to 2500 Centigrade, about p there will be a compact film of copper covering the FIG. 26.-HYDRAULIC PRESS FOR MAKING three-fourt.hs of the water represented by the above mould. THE WAX MOULD. symbol is driven off. and the gypsum falls to a coarse This film when thickened up by a layer of type powder, which then has approximately a composition metal forms the ordinary electrotype used by the expressed by the formula: printer. the gas being led through the hollow stern of the 2CaSO •. H,O In the room is a very complete set of specimens "iron " by an India rubber pipe about one-sixteenth of This expression corresponds to about 6 per cent. of illustrating the various stages of the ordinary process an inch in diameter. For " raising " the mould be water, and if the plaster in the course of manufacture of electrotyping, these having been lent by Messrs. tween fine lines, an ordinary pen may be mounted in is heated above 2500 Centigrade, and the retained Richa.rdson, Kooiman, and Isger, and the shortness of this way, the small gas jet playing on its back, and water is redt1ced much below 6 per cent., the plaster time at my disposal must make me content with dips can be taken, ink fashion, from a pot of melted will harden but slowly. In hardening, the sulphate of showing you these, rather than demonstrating every wax. A building pen, capable of holding more wax, lime reunites with water, forming a compound which stage of the process. There are also some illustrations and suitable for coarser work, may be made out of a is probably identical, from a chemical point of view, sent by Messrs. F. Plummer & Co. piece of copper wire cable, the wires being cut away with the original gypsum. The forme from which a stereotypiccast is to be made at various points, so as to make a conical termination When the mould is baked at a temperature of about by the electrotype process should be surrounded with ending in two wires only, which form the working 2000 or 210° Centigrade, the greater part of the water type-high clumps, and be filled in with plaster of point, and the tool will be more lasting if each cut·off is dri ven off, and the mould retains the 6 per cent. or Paris, as in the case of a forme for reproduction hy the end is brazed down in its place with a minute patch of so which is contained in ordinary plaster; but during ordinary plaster method. Then the forme should be spelter or sil ver solder. the long contact with the fused type metal, at a tem thoroughly brushed over with powdered black lead. The wax must now be thoroughly blackleaded by perature of about 3200 or 3ilO°, almost the whole of the All is now ready for moulding in a bed of wax. It is beating and rubbing finely powdered black lead on remainder is driven off, and a sound cast is not ob desirable to URe genuine beeswax (unbleached) and to to the face of the mould, either by hand or by a ma tained until this is the case. The reason why the thick soften it by adding to it about one-seventh of the tur chine, until every part is covered, after which the back plaster cast is not baked in the firstplace at a temper pentine sold as Venice turpentime, and when these and sides of the moulding pan are painted over with ature above the melting point of the metal, and a cast materials are melted, it is usual to stir in a little (say melted wax to render the surface non-conducting, and obtained by simple pouring in of metal, is the one thirtieth) of finely powdered plumbago (black all is ready for the depositing bath. Very much de extreme friability of the completely dehydrated lead). pends upon the nature of the black lead (plum bago, mould. Messrs. Sharrow & Anderson, who work the The wax mixture having been melted in a jacketed graphite) employed to make the surface of the mould plaster process in London and turn out about 200 stearn pan or water bath, and well stirred, it is allow conducting, and the electrotyper is often so much im music pages a day by this method, have been good ed to settle for a second or two, and a strip of paper is pressed by the deeire to obtain a "perfectly pure " enough to send me a set of specimens showing drawn along the surface to bring any air bubbles to article, or something of the" very finest quality," that the various stages-the forme and moulding frame. one side, when the wax mixture is ladled out into he pays quite extravagant prices to those who profess rough cast and dipping pan, and also a finished shallow pans, about one third of an inch deep. and to supply such. Black lead, which is a form of the ele plate, cast of soft type metal, called moulding pans (Fig. 25), ment carbon, is a mineral, and is always accompanied A modification of the plaster process exists, in which by traces of impurities, such as iron or earthy matters, the friability of the completely dehydrated plaster and, although samples containing much earthy matter mould is overcome by the expedient of making the are less desirable than those containing a small propor mould of extreme thinness, and in close contact with tion, the point at issue is mainly one of structure. an iron plate. Indeed, the mould is so thin that the Black lead ranges from hard crystalline scales to almost face of the cast is virtually made on the surface of the an amorphous mass, and neither one extreme nor the iron, the plaster in this case adhering to the iron in other is most suitable, but the kind best for our pur patches and ridges, forming reverses to the depths of pose is one which in grinding will break up into verv thin the original. minute and scales, a quality which can be recog A woodcut consisting of a close mass of fine lines, nized by a microscope examination, but a practical test is without large patches of white, or a grained photo best for the electrotyper. A moulding pan having been tint block in which there are no considerable depths. filled with wax and cooled, a plate of thin sheet metal, can be easily reproduced by a method of this kind, as having a slot about a quarter of an inch wide in it, is the mould adherent to the iron plate consists of very laid stencil fashion across from edge to edge, and is small and thin deposits of plaster which have not held firmly in position while one of the samples to be llIuch tendency to scale off, and which can be com examined is brushed through the slot for a certain pletely dehydrated by exposure for a short time-even number of minutes. The stencil having been shifted, a few minutes-to a heat about equal to that of melted other samples, perhaps to the number of twenty or type metal. Sometimes the iron plate is studded with thirty, are similarly brushed on the slab of wax, after small holes, tapering larger toward the back, so as to which it is put in the depositing bath and connected give a better hold to the plaster, but this device is es to the source of current, when the rapidity and per pecially needed when such an original as a forme of fection of the covering on the various strips will give type is moulded from, and the reliefs of plaster are nearly all the information wanted, although before finally deciding, the three or four samples which corne more considerable. A method of this kind may, in some cases, compete for rapidity with the paper out best should be tested on an actual mould having process. FIG. 25.-MOULDING PANS. rather deep and narrow lines. In this case the quarter In working by this method, the original-after being inch test strips would be no use, and a very good way .. filled ill " with plaster, if necessary, and oiled-is is to cut out a metal or card templet, which will leave, smeared over with a thin layer of mixed plaster, and these being laid out on a level slab. It is well for the say, a fourth of the mould uncovered for each sample. the iron plate to be used (this may be one plate of the pans to be very slightly warm when filled, and they A suitable black lead is generally made worse by plat casting box used for the paper process) is similarly should be filled so that the wax stands well up to or a inizing or gilding, and a black lead most suitable for a smeared over with plaster, but, naturally, the iron little over the edges. As a rule the wax does not crack soft mould is not always the most suitable for a hard must not be oiled-indeed, it may be advantageomly in cooling unless it has been adulterated with the so mould. rubbed over with the white of egg to promote adhe called Japan wax, but one remedy in this case is to Not only have many other materials than wax been sion. add a little more of the turpentine. Unless there is used in typographic electrotyping, but gutta percha is The two plastered surfaces being now pressed to gross cl umsiness in filling the moulding pans, nothing now very often used in France; also there are other gether with considerable force, ten or fifteen minutes more than a few isolated air bubbles will be formed, ways of moulding. These matters I would much like are allowed for the plaster to set, after which all that and these can be readily broken by ,ouching with a to discuss at length, but time does not permit. I may, excess of plaster which exudes from the sides is trim pointed iron rod, which may well be warmed, so as not however, refer to Mr. Clay's convenient method of med off, the mould on the iron plate is dried at about to chill the wax. The wax. when set, should, like the moulding, by which the" fillingin " of the forme with 3200 Centigrade, and the cast is made by backing up forme, be well black-leaded with finely powdered plaster is avoided. A piece of stout linen is laid on the the mould with another iron plate (or the other leaf of black lead, a soft, long-haired brush being used in its forme, and over this a sheet of India rubber, after the casting box), and pouring in metal as when operat application. The moulding must not take place until which the moulding pan is placed in position and pres ing by the paper method. A modification of this mode the wax has thoroughly cooled, as, if this were done, sure applied; in this way a general impression is ob of working can be used in making reproductions of the internal portion being softer, would very likely tained, and a second impression without the linen and medals by casting in plaster moulds, two plates of iron, exude, but the wax plates, when once cooled, may ad India rubber sheet gives a moulding of the sharp face the register between them being insured by steady vantageously be kept ready for use in a warm place of the forme. The essential point is to insure exact pins, forming the framework of the mould, the mould rather than a very cold place. register in placing the mould in position the second being then made by spreading a little plaster on each For moulding' from the type, a rather lightly built time, a very easy matter if the chase and moulding Lron surface, and compressing the original between hydraulic press, made something like Fig. 26, is used, pan are provided with corresponding pins and holes. them. the only notable features besides lightness of build be By using a soft wax, a mould of moderate size can be The original must not only be slightly oiled, but ing the shortness of the rise, and a slab of iron on the made by this method with an ordinary printing press must be inserted in a hole cut of the right size in a bed, which can be pulled out drawer fashion. The or a screw press. sheet of oiled paper, otherwise the two parts of the forme being placed on the draw slab of the press in In the depositing bath a simple solution of sulphate mou ld would not separate. such a position that it shall corne fairly over the ram, of copper, nearly saturated, is all that is wanted, and, The electrotyping process is very extensively em the blackleaded slab of wax is laid over it, and suffi although London electrotypers in many cases still use ployed in making stereotypes* of engravings, or of cient pressure is applied to mould all the details. In the Smee battery, a series-wound dynamo, driven by removing the mould from the forme, the same sort of a stearn engine, is, under ordinary circumstances, a * Among the London craftsmen the words stereotype and electrotype, care is required as when removing the plaster 11l0uld much more economical source of electricity; but the or rather "'stereo" and" electro," are used as d!stingllishing terms, and from the type ,e and wh n rem ved tllere WI'11 a I way"' b e special circumstance that favors thE.' survival of the the former term is so exclusively applied to the stereotype in type metal, � that to speak of an electrotype cast as a" stereotype" is regarded as a some superfluous wax to trlm off. The parts of the battery is the facility it offers for depositing during barbarism. . mould corresponding to the more extended whites will the Dight, when it would be an additional expense to
© 1891 SCIENTIFIC AMERICAN, INC SCIENTIFIC AMERICAN SUPPLEMENT, FEBRUARY 21, 1891. No. 790. 12623
keep th e engine running ; but even in this case second of working, and Mr. Peter Barry has been good made as to the practicahility of usi[Jg rubber stereo ary batteries charged by a dynamo during the day enough to send me some very excellent casts which he types on rotary printing machines, as they would would probably be more economical. has made. easily adapt themselves to the required curves, and Here is a small Siemens series-wound lighting dyna Stereotypes in high steel might perhaps be made by might be expected to save power in the working of mo (D 6), a kind of machine which would in many casting in moulds of lime compressed dry, and I have the machines. Fatty ink soon softens and destroys cases be better suited to the needs of an establishment obtained promising results by this method, but should rubber stereotypes, so that an ink made by dissolving for typographic electrotyping than are some of the such be req uired they could, I think, be made, even if an aniline color in glycerine is generally used. These specially made depositing machines, which are primari of considerable size, by the "striking " method indi will generally fad e rather rapidly on exposure to the ly intended for operations in which much heavier de cated in Lecture I. light, but. by dissolving nitrate of silver in glycerine posits are required, and this machine, while consuming I findth at by using a piece of wet asbestos mill board we have an ink which does the reverse. At first it only about a quarter of a horse power, and running as a material for making the mould, we can stereotype gives a colorless impression, or nearly so, but on expos· quite slowly, will give a current of about twenty am in brass or iron by a method quite comparable to the Ilre to light it gradually becomes deep brown. peres with a tension of eight volts. It is now giving ordinary paper mould process, and I will illustrate this Elastic stamps, which can be used with the ordinary about that current, and is depositing copper over an to you by making a cast in brass. printer's ink, can readily be made of any required area of something like two square feet, at the rate of When the asbestos millboard, which may be about hardness with a gelatinous composition similar to that about 184 grains on the square foot per hour, and you an eighth of an inch thick, has been wetted, it is press used for the ordinary printers' inking rollers. The see it gives good deposit with this current of no less than ed against the forme by means of a serew press (there is making of these is a very simple ILatter indeed. A 10 amperes to a square foot of surface. We might have no need to work from a previously made stereotype in piece of very thin sheet lead, such as is sold for cover six or eight depositing cells in series, each depositing this case), removed, dried a t a heat bordering on dull ing damp walls, say about an eightieth of an inch thick, the same amount, and giving a total deposition of frow redness, and with a similar piece of plain asbestos mill is slightly oiled, laid over the forme, and beaten with 2,000 to nearly 3,000 grains of copper per hour. In board clamped in the usual stereotype casting box, the moulding brush until a satisfactory impression is usinp,'one " series " machine by itself some precautions with a bent iron wire gauge between them; the brass obtained, after which it is laid on a level, flat surface; are necessary to prevent reversal, but when several is then poured in at the top. In this case there is no a border is placed round it, and a melted gelatinous machines are in use, one can be used to excite the field need to warm the casting box, the slow conducting mixture is poured over it ; any mixture, sueh as is used magnets of the others, an arrangement which con quality of the asbestos preventing all chilling of the for printers' roller composition, will serve, although duces much to convenience of working, and is, more metal. something rather harder will often be required , By over, suitable for the charging of secondary batteries. The body of a cast made in this way is rough, and soaking a fine hard gelatine (Coignet's silver label gela When a sufficient thickness of copper (say 1-30th to generally somewhat unsound, being cast against the tine, for example) in water till it has absorbed a bou tits 1-40th of an inch) has been deposited upon the wax spongy body of the asbestos millboard, but the face, own weight of water, and then melting it with half as mould, hot water is poured on the back of the copper which is cast in contact with the hard and compressed much glycerine, a serviceable hard composition is ob electrotype (called the .. shell ") to disengage it from portions of the mould, is sound and good. tained, but with some tendency to shrink, which can the wax mould, and the rough back of the shell is . To show you what can be done in the way of typo be met by adding more glycerine, and heating for some " tinned " with a coarse solder consisting of equal graphic brass casting, Mr. Nettleton, of Barnsbury, time in a flat dish over boiling water, so as to evapo weights of tin and lead, such coarse solder having less has been good enough to send me samples of his cast rate some of the water. tendency to run through any holes in the shell than brass type, both in the rough and finished; these, I Under the head of auto·stereotyping I propose to would be the case with a solder having a full propor· understand, are cast in iron moulds. deal with a few of those methods in which lines are tion of tin. This alloy is usually granulated by being The various photo-stereotype or photo-typographic cut out or indented on a level surface by some sort of poured through a gauze net into water, and it should methods do not come within the scope of the present sketching or writing action, this writing being then be quickly dried, otherwise some oxidation will take lectures, but I have now the opportunity of showing used as a mould in which is cast a stereotype, from place. The shell having been trimmed to the outside you some Arabic printing types cast in matrices re which the writing or drawing may be printed, and of of the clump marks is laid face downward in a shallow produced by photographic mea.ns from an impression late years such methods have come much into use, and iron pan (backing pan), which can be heated either by taken from type of a larger size. In this case the re have acquired considerable importance. heing supported on the surface of a bath of melted production was made for Messrs. Stephen Austin & If one simply takes a blunt style, and, while using ba cking metal (generally marie rather soft ; lead 16 to Sons, of Hertford, by Mr. Alfred' Dawson-so well some considerable pressure, with this makes a sketch 18 parts, antimony 1 part, a little tin-say three-fourths known as a successful worker in photo-engraving on a very soft paper board * or a blotting pad, a mould of a part-being added, unless the lead used is known methods, and I am told the cost was only a small frac is obtained which, if cast from, as in the ordinary pa to contain tin) or by a gas burner. If the shell tends tion of what the expense would have been if punches per process of stereotyping, yields a block that can be to curi, it is easy to keep it tolerably flatby laying iron had been cu t. rapidly deepened by the engraver, and may serve very bars on the level edges left by the clumps, and the I also have placed upon the table reproductions well as an extemporaneous illustration for a newspaper, clean back of the shell ie now brushed over with the which I made some years ago of some letters from a tn d as the material for this sort of thing is always at acid chloride of zinc solution (see footnote p. 12867, Lec book printed by Sebastian Gryphins, of Lyons, in 1539, hand in a newspaper office, it is a very convenient ture 11.), and sprinkled with the granulated solder, a and alongside them are the matrices and body mould. method to employ when only a rough sketch is re final brush over with the solution being given if the In this instance each letter, cut out of a photo-type quired, and by a very simple expedient, the labor of solder does not spread to all parts immedi[l,tely. The block, was set separately in a level plate of metal, at cutting away the whites of such a cast may be obviat backing pan may now be removed from the source of the required distance and a thick electrotype cast was ed, provided there is no objection to the sketch appear heat, and, before the solder has time to set, melted made of the whole. This was strengthened by a back ing on a ruled or cross-hatched ground. Before mak backing metal is poured on in a steady stream, com ing of soft metal, and when cut up it formed the ing the sketch, a hard impression of a lined, dotted, or mencing in the middle and traveling outward as a matrices. cross-cut block is made on the paper pad, and the spiral, so as to build up a thickness of at least a pica Celluloid , as a material for stereotyping, has been sketch is afterward made with the style. A tcast now all over the shell, * the clump edges of which may be proposed by Jeannin, who makes his mould by mix being taken, the ruling or dotting gives sufficient sup turned up so as to form a dish, unless iron bars have ing the soft unfused oxide of lead known as massicot port on the whites, and the sketch shows as lines on been placed round as before mentioned. into a stiff paste with glycerine, and if baked for about the tinted gronnd. The " electro " generally requires some hammering five minutes in conta0t with the forme, at about 120" The above is eE'sentially a process for rough or hasty upon a level iron slab to bring up "sinks" (Lecture II.), Centigrade, the mould becomes hard, and separates. work of the crudest character, and we now pass on to and the leveling of the hack is generally done by a The celluloid is then softened at about the same tem one of the earliest llIethods, and perhaps the best of all special surfacing lathe, as in the case of stereotypes by perature, and forced into the mould. if perfection of result is considered, nalllely, the glypho the plaster process. There is often a little after work '.rhesame kind of mould answers well for making graphic pro(�ess, invented by Ed ward Palmer about to be done on the face of the electrotype, this being stereotype casts in the so-called Spence's metal (sul 1841. A thin coating of wax, whitened by a suj: itable done by a workman called a "picker," who must be phur slightly hardened), an excelient composition of pigment (white lead or other heavy lead compounds deft in the use of engraving and soldering tools, and in this kind being the following : answer best), is spread on a blackened copper plate, the case of fine cut work it is desirable to mount ele.:J and the sketch is made on this with a point, so as to� Sulphur ...... 100 parts. types on solid blocks of type metal, and for this pur lay bare the black copper, the dark lines thus pro Finely powdered pumice stone ...... 30 " pose one of the fusible solders referred to in the last d uced showing the artist the progress of his work. Any Native sulphide of antimony...... 4 lecture may be used ; the top of the block and the bot lettering- may be donewith stamps or types, the wax tom of the " electro " being both well amalgamated It requires careful melting, as if over-heated the sul grou nd being softened by a little heat if necessary. The with the solder, then brought into close and solid con phur would pass into the viscous modification, and it extended whites are now raised by the building process tact while sufficiently heated. A sort of cold soldering should be well stirred before pouring. already described in reference to the wax modld for is sometimes employed, the two surfaces being sepa The use of India rubber stereotypes has not gone electrotyping, the hot pen there mentioned being used rately amalgamated with mercury, and then held in much beyond their employment as hand stamps. The for filling in between the finer lines, and during this close contact by a press till the excess of the mercury mould in which the rubber is vulcanized is generally process any false line may be covered ; after which an has diffused intothe mass.t made of a mixture of plaster of Paris and French electrotype cast is made from the wax mould. Binger, The casting of stereotypes in brass (the material chalk, the forme being " filled in " with soap, to insure in his " Glyphographie," published at Amsterdam in used for the earliest stereotypes on record) and in easy separation. As only small casts are ordinarily 1850, gives as fine examples of work by this process as other refractory metals, has not yet become general, made, it is convenient to mix the plaster and French any since done. It is now very extensively elllployed, although the extensive present use of rotary and other chalk (equal parts of each answers very well) to a and it is understood to be substantially the method by machines for printing and branding directly upon paste with water, and to spread this on a level sur which several well known firms prod uce blocks. As it wood is likely to create a demand for iron and per face, and to force the forme irtto it. At other times would be in many cases obviously inconvenient to sub· haps steel stereotypes. the bed of plaster is moulded on the type with two mit the traced wax plate itself as a proof, a photograph Iron or brass casts can be readily made in sand or successive pressures, the first with a cloth covering. is often sent. loam moulds, but in moulding it is so much more con and the second without a cloth, these operations re There are several processes roughly classed as " day" venient to mould from an ordinary stereotype than quiring a means of keeping register, and being similar processes, in which a mineral mixture is used on the from the type forme, that I have no hesitation in very to Mr. Clay's method of moulding in wax for electro· copper plate, and a cast is made direetiy in stereotype confidently recommending this course. As moulriing typing. metal from the tracing made on this surface, and I will frames, two ordinary printers' chases may be used, one If a large mould is required, nothing is better than illustrate to you the form of this process which I have having register pins fitt.inginto corresponding holes in M. Jeanuin's composition of massicot and glycerine, found to work best in my own hands. the other, and both being furnished with a few cross while simple plaster of Paris answers very well, especi I now take a plate of copper which has been rough wires to support the sand ; but a gap should be cut ally if after drying it is hardened by saturation with ened by glass paper blackened by a solution of per away from the top of one to form an ingate. One a solution of shellac in alcohol. The mould having chloride of platinum, rubbed over with white of egg, part of Stourbridge clay and two of Bathbrick dust been obtained, is dried and warmed, and some uncur and then flooded with a whitewash composed as fol forms a very good mixture, and after this has been ed rubber, mixed (by strong rollers) with about one lows : Stereotype paste,as given on p. 12365, Lecture II., slightly damped, well rammed, and carefully leveled tenth its weight of sulphur,* is softened by a gentle 6 whiting, 24 oz.; water, 3 pints. Enough should into the casting box, the pattern stereotype is oiled heat, and forced into the mould, after which the whole beoz. aj' lowed to remain on the plate to form a layer and is forced by a press into the 80ft surface. A lit· is exposed to a heat of 140' to 150' Centigrade for about I-20th to 1-30th of an inch thick, and the plate is then tie brick dust being sifted on to serve as a parting half an hour, during which time the sulphur reacts set in a horizontal position to dry. A design can be material,t the second chase is placed in position and chemically on the rubber, and what is called vulcani readily traced with a point through.the friable ground, filled with the moulding mixture, after which the zation results, the rubber no longer becoming plastic and after the mould has been dried at about 200° Centi frames are separated, the pattern removed and the by heat. Hot presses for the vulcanization of rubber grade, a cast is made in the casting box ordinarily used mould is baked. For casting, the two frames may stamps are now sold at a morierate price, or a simple for the paper process. Apart from the operation of be conveniently clamped up in the ordinary stereo arrangement, which I showed in this room nine years deepening the whites of the block and the making of type casting box (Fig. 4), a few channels being cut for ago, may be used. It consists of a cast iron fish kettle, the sketch, the whole work can be perforllled in ten the escape of air. upon the bottom of which is cast a slab of type metal minutes or so. The mixture used for coating the plate The mould should be well dried, but not too rapidly, an inch thick. Inside the kettle is placed a small press, may serve to raise the whites on the mould, this prepa or it is rather liable to lose its face by a kind of granu like a copying press in miniature. By the side of the ration being put on by means of a pipette, but such a lation or scaling, and the metal should not be so hot press stands a small iron cup, containing glycerine, course is not to be recolIlm ended, as it involves delay as to cause " sand burning." On the table are moulds and in thiS fluid is immersed the bulb of a thermome in drying, and there is increased chance of the coating and casts which I have made to illustrate this method ter, the stem of which projects through a hole in the leaving the copper. The most essential point is the cover of the kettle. By means of a small gas stove, use of albumen on the roughened plate, this enabling * The French electrot.ypers always place gauges on the clump marks heat can be supplied to the apparatus, and it is easy a friable mixture to hold on sufficiently for practical when pouring on the backing metal, and, just as it is on the point of solidifying, the platen of a press is brought down on it. In this way the to so adjust the gas supply that the thermometer shall purposes. need of planing the back is often obviated, and the tendency to smks indicate a tolerably constant temperature of say 140' Closely analogous to the autographic stereotyping and irregularities of the face is diminished. Of course, when the above or 150' Centigrade, the slab of metal serving as an methods are those in which a machine analogous to a course is taken, the t.inned shell must be placed on an accurately planed equalizer of heat. surface. The French method is better adapted for rather thick than thin typewriter is used to make a matrix, letter by letter, shells. Mr. John Leighton introd uced rubber stereotypes on such a material as flong,wood, or soft dry pul fJ t As a means of fastenmg types together to form solid stamps lstereo abou t twenty-six years ago, and his firm has been good * A thick " wood middle ,. or pulp board answers well. types in the sense in which Didot first used the word)� the mercurial enough to send here samples illustrative of their manu method of 801dering is allmimble, and it is also fairly 8ati�factory lor facture and use, a subject which in itself might well t An assemblage of ordinary brass " rulcs," plain, dotted, or waved, fixiHg a letter into a stereotype plate provided that the tit is ac may be used. occupy a whole lecture. At one time experiments were cllrate. :j: Palmer kept a well known philosophical instrument shop in N ewgatc t As the pattern is generally forced in so as to be level with the sur Street, aDd was succeeded by Horne & Thornthwaite. face of t.he mould, a sheet of oiled paper may l)e laid over instead of * Mixtures of this kind can be obtamed where materials for making § The clean copper can be blackened by a weak solution of silver nitrate using parting sand. rubber stamps are Bold. or platinnm tetra-chloride.
© 1891 SCIENTIFIC AMERICAN, INC 12624 scn�NTIFIC AMERICAN 8UPPLEMENT, No. 71)0. FEBRUARY 21, 1891
boards, and in Guillot's " Graphitype " (Lecture I., p. the sphere above, where a device. revolved by the in theories of combustion (Ueber die Luft und das 12343) we have the parent of all such methods. 'l' he flow, finishes the saturation. Ji'e ner), nor was this his first discovery of a substance weak point in all these processes is the difficulty of After the desired pressure has been obtained, say 12 hitherto unknown to sciflnce. We can easily imagine, luaking corrections or alterations, and no printing to 14 atmospheres for the siphons, or 6 to 8 for the then, with what enthusiasm Scheele-for that was his method which does not provide for this is likely to be bottles, the tilling is begun. name-plunged into the study of the strange liquid in generally accepted : the only matrix method which The indicating flask, I, shows the quantity of gas the occasional respite that was granted him from the gives this facility in a high degree being the matrix contained in the generator, as well as the quantity of pestle and the dispensing counter. He soon found setting method of Herhan (Lecture r., p. 12343), which liq uid sucked from the reservoir by means of the that the sweet substance was not the product of olive lIlethod, if operated in connection with a typesetting pipes, J and L. oil alone, but that other oils and fats would yield it Illachine. should be quite as rapid as the typewriter The bottling is effect.ed through the annexed ap under the same treatment, so he named it the " sweet methods, aud it allows alterations as readily as when paratus, which is easily maneuvered. Two rods actu principle of fats, " or " oil sugar." Soon after, his work ordinary types are used. acted by pedals eause the 1Il0uth of the bottles or was cut short by death. More than a century has passed since Scheele's discovery, yet it is scarcely fifty AUTOMATIC APPARATUS FOR THE MAN U years since " oil sugar " was found to be of practical FAC'r UlU� OF CARBONATED WAT ERS. value, pxcept, perhaps, for a limited use in medicine. Many famous chemists had taught the world much as 'IRE mauufacture of carbonated waters, which hard to its nature and production, had given it the more l y seemed as if it was to leave the domaiu of pharmacy, formal nallle of glycerine, derived from a Greek word has so increased that it now constitutes a very import· meaning sweet., but to the every-day world the sub ant industry. In nature, we fiud a large nUluber of stance remained only a curiosit.y. Nowadays, every mineral waters that contain enough carbonic acid gal' one is familiar witll the clear, t.hick liquid so COllllllon to give thew a pung-ellt taste and to make them effer Iy used for toilet purposes. Its sooth ing and softening vesce in the air. Such are the seltzer water of Ger effect on dry or iIJfiallled skin is the qmdity by which many, the Saint Galmier and Vichy waters of 1!' rance, it is best known in llIost households, but. few people the spa of Belgium, etc. The name selt.zer water has have any idea of the variety of purposes for which gly heen given to a sort of imitation of the natural car cerine is used. This will not seem strange when we bonat.ed water obtained by dissolving a large propor find how many valuable properties are possessed by tion of carbonic acid gas in pure water. This name is this remarkable liquid. Among the most striking not very apropos, for natural seltzer water contains of these are its great solvent power, its chemical stabi Hom ething else besides carbonic acid gas. It would be lity, and its sweetness. Besides these, it is not indi better, then. to call this beverage simply carbonated gestible, will not. evaporate, aIJd, owing to this and its water. This water is now used in large quantities. hydroscopic qualities, will prevent drying and harden wixed with wine or sirups. It differs from commol! ing of materials with which it, is llJixed. These pe water only in containing four or five times its volume culiar qualities make it IIIOSt. val uable in the prepara of carbonic acid gas, which communicates to it stimu tion of medicines and various food prod ucts, as pre lating properties that in many persons aid the action serves and mustards, Iikewi,;e in beer, wines and other of the stomach. bottled goods, where it is said to act as a preservative. The- carbonic acid tha t sen'es to prepare this gaseous The fact that strong 001 utiolls of glycerine and water water is obtained by causing sulphuric acid to act will not freeze in the lowest winter temperature has its npou chalk. Chalk is carbonate of lime. that is to say, use in our .. wet " gas weters. In short, the list of a substance resulting from the combination of carbonic purposes to which this llIost useful liquid is put is al acid with lillie. As sulphuric acid has more affiuity for llIOSt exhaustless. A lIIong the 1II0re illlPortant indus lime than carbonic acid has, it combines with it to tries in which it is used am vulcanizing India rubber, forlll sulphate of lillie and sets free the carbonic acid silvering and gildiug' glass, dressing leather for kid ill t.he state of a gas. gloves, preserving allatOluical and botanical specimens, Fig. 1 represents the installation of a new automatic FIll. 2. -SEOTION OF THE GAS UEN El{ATOR. and the manufacture of what is, perhaps, the ItrOst apparatu� constructed by Mr. Durafort, which pro powerful explosive kuown to science-without whose d uces carbonic add through the use of bicarbonate of aid some of the grandest triumphs of modern engineer siphons to bear against a rubber coliar for the tilling. soda instead of lime. ing would have been illlpo�sihilities-nitro-glycerine. The communication with the saturator is regulated by It. Scientifically considered, glycerine is JJJost interesting. consists of a gas generator and of a siphon and a cock iudependent of each system. The filling is kept bottle tilling device. Mention has already been llIade of many of its physical up by means of HIe pump, which is actuated either by The generator ha� the form of a gasometer. characteristics. It is hand or by a IlIotor. seen ill section iI. Fig. 2. In a pure state glycerine iR somewhat more than a This apparatus, as Illay be seen, is very simple, and Two iron uprights fixed to the tank by bolts support fourth heavier than water (1'269). After long exposure i� capable of tilling 1,000 bottles a day. -La Production to a freezing temperature it will deposit rhombic a cast iron cross piece provided with two pulleys. Two Industrielle. eord s an> attached to the gas holder, R, on the one crystals resembling those of sugar candy. Strangely enough, when quickly cooled to very low teJJJperature hand, and to two counterpoises on the other. In the GLYCERINE. iuterior of the tank, D K, there is a leaden reservoir, -40 deg. Fahr.-it forllls a gUlIlmy mass which will iu to which acidulated water is introduced through the MANY years ago, in an obscure Illlnillg Yillage in not harden nor crystallize. Indeed, it was not till 1867 aperture, D. With the holder, R, there is conneCted a Sweden, the apothecary, while making lend plaster in that it was thought possible to crystallize it. The leaden receptacle, B, into which hicarbouate of soda is the ordinary way by heating olive oil with litharge boi ling point of glycerine is about 490 degrees Fahr. introduced through the aperture. C. and water, chanced to notice that the liquid which At this point it. decolllposes slightly. As already stat It is easy to see how the automatic prod uction of gas was mingled with the pasty lead coni pound had a ed, glycerine will not evaporate at ordinary tempera is effected. strangely Rweet taste. On further invest.igation he tures, but at the boiling point of water (212 degrees As soon aR gas is taken froUl the cock, J, the holder found that the sweet taste was cau�ed by the presence Fahr.) there is a perceptible loss. Pure glycerine will tlelScends, and the bicarbonate of soda, brought into of an oily liquid which was 'ii�80Ived in the water. No burn readily, if first heated to about 300 deg. Fahr., contact again with the acidulated water, reproduces such substance was descri bed in the books of the day. giving a pale blue flame similar to that of alcohol. the !!as iu measure as it is consumed. Evidently a discovery had beeu made. The discoverer, Heated intensely it decomposes into acrolein, a most Tile gas stored up in the holder is sucked out by the although poor and with slight advantages of educa· pungent sllJeliing compound, one whiff of which is pump, which, at the sarue ti llie, takes a certaiu quanti tion, was a man of 1II0re than ordinary ability. Al usually sufficientto fix it indelibly on the llIelllory. To ty of water from the reservoir. This suction is regu ready he had attl'acted the attentioll of the learned the chemist glycerine is an alcohol, being, like other lated by a cock, S. The pump forces the mixture iuto men of the day by publishing his quaint chemical alcohols, a hydrate of an .. organic radical"-that is to say, the hydrate of a combination of carbon and hydro gen which forms salts as if it were .a metallic element. From its chemical behavior glycerine can be consider ed a "tri-atomic alcohol," or tri-hydrate, with the fo rmula C3H.(OH)3, on the same analogy as sodic hydrate, NaOH, or calcic hydrate, Ca(OH),--the group represented by the formula C,H. acting as a base and known chemically as glyceryl or propenyl. Just as we can make salt.s of a metal from the hydrate, so can we make salts of glyceryl in essentially the sallie way, although the methods employed are different. Nitro-glycerine, so called, is one of these salts ot gly ceryl, being an impure tri-nitrate (C,H.[NO,],). By. far the most important salts of glyceryl are oils and fats. The majority of these are salts of glyceryl and or ganic acids. The principal of these acids, out of many which are present in our COIIIHlon fat.s, are stearic, oleic, and palmitic acids. We now understand how it was that Scheele made his glycerine. We remem bel' that. olive oil was the basis of his lead plaster. This oil is, in the main, glycel'yl oleate (C,H,[C1sH,,0,],). Hence the reaction between the lead and the oil and water can he expressed by the following equations : 2 C,H,(CIBH"O,). + 3 PbO + 3 H,O Glyceryl oleate. Litharge. Water.
= 2 C,H,(OH), + 3 Ph(018H"O.h Glycerine. Lead oleate (lead plastel'). For mauy years this reaction was the basis of the manufacture of glycerine. Oheaper fats than olive oil, of course, were used, while traces of lead in solution were removed by sulphureted hydrogen. As the use of glycerine became more extensive, there arose the necessity for a cheaper method of production. Atteu tion na tnrally was directed to the spent lye of the soap manufacturer, for soaps are sod ium or potassium salts, principally of stearic acid, made by a reaction similar to that used in making lead plaster, but sub stituting caustic alkalies for litharge. By the method of soap manufacture. however, the liquors cOfltaining the glycerine are so contaminated by alkalies and salt, and are /;0dilut ed, that until recently it has not paid to recover the glycerine. A process which has proved 1II0St profitable has been invented to decompose ani lII al fat directlv into stearic acid and glycerine, by sub jecting it to the action of superheated steam, at a temperature of about 300 deg. Fahr. The resulting glycerine is concentrated and purified by stearn distil lation, while the stearic acid, which much resembles wax, and in no way answers to our ordinary concep tion of an acid, is in great demand for candles. In this way thousands of tons of glycerine are made yearly, not, to mention the immense number of excellent candleR which are also pl'()dlld.� of' the proceRs. PIO, J. -ATJ'J'( )M A,), lC APl'AHA'l'U8 .FOR 'I'HR MAN UFAC'l' VH.E 0.1<' CARBON A'I' lm WA'1' �j ltK. popul(tT BI:ie1WP .Nems.
© 1891 SCIENTIFIC AMERICAN. INC