10 ENCYCLOPEDIA PERTHENSIS. FOU FOUNDERY. Ar the conclufion of our laft Volume, (fee page 718,) we inferted this word in its proper order, with its different definitions, but had not fufficient room remaining in that volume to infert the various branches of this art, in the complete manner, which an article of fuch importance required. 1. FOUNDERY OF BELLS. The metal, it is to be obferved, is different for bells from what is for ftatues; there being no tin in the latter; but there is a 5th, and fometimes more, in the bell-metal. The dimenfions of the core and the wax for bells, if a ring of bells especially, are not left to chance, but muft be measured on a fcale, or diapafon, which gives the height, aperture, and thicknefs, neceffary for the feveral tones required. It is ou the wax that the feveral mouldings and other ormaments and infcriptions, to be reprefented in relievo on the outside of the bell, are formed. The clapper or tongue is not properly a part of the bell, but is furnished from other hands. In Europe, it is ufually of iron, with a large knob at the extremity; and is fufpended in the middle of the bell. In China, it is only a huge wooden mallet, ftruck by force of arm against the bell; whence they can have but little of that confonancy fo much admired in fome of our rings of beils. The Chinese have an extraordinary way of increafing the found of their bells, viz. by leaving a hole under the cannon; which our bell founders would reckon a defect. The proportions of our bells differ very much from thofe of the Chinese, as well as their fizes. See BELL, N° 1, § 5. In ours, the modern proportions are, to make the diameter 15 times the thickness of the brim, and the height 12 times. The parts of a bell are, 1. The founding bow, terminated by an inferior circle, which grows thinner and thinner. 2. The brim or that part of a bell where on the clapper ftrikes, and which is thicker than the reit. 3. The outward finking of the middle of the bell, or the point under which it grows wider to the brim. 4. The waist or furniture, and the part that grows wider and thicker quite to the brim. 5. The upper vafe, or that part which is above the waift. 6. The pallet which fupports the ftaple of the clapper within. 7. The bent and hollow branches VOL. X. PART I, FOU of metal uniting with the cannons, to receive the iron keys, whereby the bell is hung up to the beam, which is its fupport and counterpoife, when rang out. The bufinefs of bell-foundery is reducible to three particulars. 1. The proportion of a bell, 2. The forming of the mould And, 3, The melting of the metal. There are two kinds of proportions, viz. the fimple and the relative; the former are thofe proportions only that are between the feveral parts of a bell to render it fonorous: the relative proportions eftablish a requifite harmony between feveral bells. The method of forming the profile of a bell, previous to its being caft, in which the proportion of the feveral parts may be feen, is as follows: the thicknefs of the brim, C1, Plate CLV. fig. 12. is the foundation of every other meafure, and is divided into three equal parts. Firft, draw the line HD, which reprefents the diameter of the bell; bifect it in F, and erect the perpendicular Ff; let DF and HF be alfo bifected in E and G, and two other perpendiculars E e, Ga, be erected at F and G; GE will be the diameter of the top or upper vafe, i. e. the diameter of the top will be half that of the bell; and it will, therefore, be the diameter of a bell which will found an octave to the other. Divide the diameter of the bell, or the line HD, into 15 equal parts, and one of thefe will give Cr the thicknefs of the brim: divide again each of thefe 15 equal parts into three other equal parts, and then form a fcale. From this fcale take 12 of the larger divifions or two 15ths of the whole scale in the compafs, and fetting one leg in D defcribe an arc to cut the line Ee in N; draw ND, and divide this line into 12 equal parts; at the point 1 ere& the perpendicular 1C 10, and Cr will be the thickness of the brim ≈ one 15th of the diameter; draw the line CD: bifect DN; and at the point of the bisection 6 erect the perpendicular 6 K 1 of the larger divifions on the fcale. With an opening of the compafs equal to twice the length of the fcale or 30 brims, fetting one leg in N, defcribe an arc of a circle, and with the fame leg in K and the fame opening, defcribe another are to interfect the former: on this point of interfection as a centre, and with a radius equal to 30 brims, defçribe the arc NK; in 6 K produced take KB of the larger measure of the fcale or of the brim, and on the fame centre with the A radius radius 30 brims defcribe an arc AB parallel to NK. For the arc BC, take 12 divifions of the fcale or 12 brims in the compafs; find a centre, and from that centre, with this opening, defcribe the arc PC, in the fame manner as NK or AB were defcribed. There are various ways of deferibing the arc Kp; fome defcribe it on a centre at the diftance of nine brims from the points p and K; others, as it is done in the figure, on a centre at the distance only of feven brims from thofe points. But it is neceffary first to find the point p, and to determine the rounding of the bell p 1. For this purpose, on the point C as a centre, and with the radius C 1, defcribe the are I pn; bifc&t the part 1, 2, of the line D n, and erecting the perpendicular p m, this perpendicular will cut the arc Ipn in m, which terminates the rounding I p. Some founders make the bendings K a third of a brim lower than the middle of the line DN; others make the part CID more acute, and inftead of making C1 perpendicular to DN at 1, draw it one 6th of a brim higher, making it fill equal to one brim; fo that the line D is longer than the brim C. In order to trace out the top part Na, take in the compafs eight divifions of the fcale or 8 brims, and on the points N and D as centres, defcribe arcs to interfect each other in 8: on this point 8, with a radius of eight brims, defcribe the ark Nb; this arc will be the exterior curve of the top or crown; on the fame point 8 as a centre, and with a radius equal to 73 brims, defcribe the arc A e, and this will be the interior curve of the crown, and its whole thicknefs will he one third of the brim. As the point 8 does not fall in the axis of the bell, a centre M may be found in the axis by deferibing, with the interval of 8 brims on the centres D and 11, arcs which will interfect in M; and this point may be made the centre of the inner and outer curves of the crown as before. The thicknefs of the cap, which ftrengthens the crown at Q, is about one third of the thicknefs of the brim; and the hollow brauches or ears about one fixth of the diameter of the bell. The height of the bell is in proportion, to its diameter as 12 to 15, or in the proportion of the fundamental found to its third major: whence it follows that the found of a bell is principally compofed of the found of its extremity or brim, as a fundamental of the found of the crown which is an octave to it, and of that of the height which is a third. The particulars neceffary for making the mould of a bell are, 1. The earth: the moft cohefive is the beft; it muft be well ground and fifted, to prevent any chinks. 2. Brick ftone; which muft be used for the mine, mould, or core, and for the furnace. 3. Horfe-dung, hair, and hemp, mixed with the earth, to render the cement more binding. 4. The wax for infcriptions, coats of arms, &c. 5. The tallow equally mixed with the wax, in order to put a flight lay of it upon the outer mould, before any letters are applied to it. 6. The coals to dry the mould For making the mould they have a fcaffold confifting of four boards, ranged upon treffels. Upon this they carry the earth, grofsiy diluted, to mix it with horse-dung, beating the whole with a large fpatula. The compaffes of conftruction are the chief inftrument for making the mould: They contist of two different legs, joined by a thir piece. And laft of all, the founders fhelves, o which are the engravings of the letters, cartridges, coats of arms, &c. They firft dig a hole of fufficient depth to contain the mould of the be1 together with the cafe or cannon, under ground; and about fix inches lower than the terreplain where the work is performed. The hole muffle wide enough for a free paffage between the mould and walls of the hole, or between one mouid and another, when several bells are to be caft. At the centre of the hole is a stake erected, that is strongly fastened in the ground. This fupports an iron peg, on which the pivot of the fecond branch of the compaffes turns. The flake is encompaffed with a folid brick work, perfectly round about half a foot high, and of the propofed be diameter. This they call a mill flone. The parts of the mould are, the core, the model of the b and the fhell. When the outer furface of the core is formed, they begin to raife the core, which is made of bricks that are laid in courfes of equ height upon a lay of plain earth. At the lying of each brick, they bring near it the branches c the compaffes, on which the curve of the core is fhaped, fo as that there may remain between it and the curve the distance of a line, to be, afterwards filled up with layers of cement. The work is continued to the top, only leaving an opening for the coals to bake the core. This work is covered with a layer of cement, made of earth and horfe-dung; on which they move the compares of conftruction, to make it of an even fmoothnet every where. The first layer being finished, they put the fire to the core, by filling it half with coals, through an opening that is kept fhut during the baking, with a cake of earth that has been ferarately baked. The firft fire confumes the fake, and the fire is left in the core half or fometimes a whole day; the fift layer being thoroughly dry, they cover it with a fecond, third, and fourth; each being fmoothed by the board of the compa fes, and thoroughly dried before they proceed to another. The core being completed, "they take the compafles to pieces, with intent to cut off the thickness of the model, and the compaffes are immediately put in their place to begin a fecon piece of the mould. It confifts of a mixture of earth and hair, applied with the hand on the core, in feveral cakes that clofe together. This work is finifhed by feveral layers of a thinner cement of the fame matter, fmoothed by the compaffes, and thoroughly dried before another is laid on. The first layer of the model is a mixture of wax and greafe fpread over the whole. After which are applied the inferiptions, coats of arm, &c. befmeared with a pencil dipped in a veffel of wax in a chafing difh: this is done for every letter. Before the fhell is begun, the compaffes are fake to pieces, to cut off all the wood that fills the place of the thickness to be given to the hell. The first layer is the fame earth with the raft, fifte very fine; whilft it is tempering in water, it is mixed with cow's hair to make it cober The whole being a thin cullis, is gently poured on the model, that fills exactly all the finuofits of the figures, &c. and this is repeated till the whole is two lines thick over the model. When 1 2. FOUNDERY OF GREAT GUNS AND MORTAR PIECES. The method of cafting thefe pieces is different from that of bells: they are run mafly, without any core, being determined by the hollow of the fhell; and they are afterwards bored with a steel trepan, that is worked either by hores or a water mill. For the metal, parts, propor tions, &c. of thefe pieces, foe GUNNERY. this layer is thoroughly dried, they cover it with a earth, through which the metal mut run, from fecond of the fame matter, but fomewhat thicker; the hollow of the rings, between the fhell and the when this fecond layer becomes of fome confif- core. They fioke the infide of the thell, by tence, they apply the compafles again, and light burning fraw under it, that helps to smooth the a fire in the core, fo as to melt off the wax of the furface of the bell. Then they put the hell in the infcriptions, &c. After this, they go on with the place, fo as to leave the fame interval between other lays of the shell, by means of the com- that and the core; and before the hollows of the pales. Here they add to the cow's hair a quan. rings or the cap are put on again, they add two tity of hemp, fpread upon the layers, and after- vents, that are united to the rings, and to cach wards imoothed by the board of the compaffes. other, by a mafs of baked cement. After which The thickness of the fhell comes to 4 or 5 inches they put on this mafs of the cap, the rings, and lower than the mill ftone before obferved, and fur- the vent, over the hell, and folder it with thin rounds it quite close, which prevents the extra- cement, which is dried gradually by covering it vafation of the metal. The wax fhould be taken with burning coals. Then they fill up the pit out before the melting of the metal. The ear of with earth, beating it ftrongly all the time round the bell requires a feparate work, which is done the mould. The furface has a place for thfire during the drying of the feveral incrufiations of and another for the metal. The fire place has a cement. It has 9 rings: the 7th is called the large chimney with a fpacious ath-hole. The furbridge, and unites the others, being a perpendi- nace which contains the metal is vaulted, whofe cular fupport to strengthen the curves. It has an bottom is made of earth, rammed down; the reft aperture at the top, to admit a large iron peg, is built with brick. It has four apertures; the beat at the bottom; and this is introduced into firft, through which the flame reverbirates; the fe two holes in the beam, faftened with two ftrong cond is clefed with a ftopple that is opened for fron keys. There are models made of the rings, the metal to run; the others are to feparate the with maffes of beaten earth, that are dried in the drofs or fcoriæ of the metal by wooden rakes: fire, in order to have the hollow of them. Thefe through these last apertures paffes the thick fuloke. rings are gently preffed upon a layer of earth and The ground of the furnace is built floping, for tow's hair, one half of its depth: and then taken the metal to run down. out, without breaking the mould. This opera tion is repeated 12 times for 12 half moulds, that two and two united may make the hollows of the ha rings; the fame they do for the hollow of the Lridge, and bake them all, to unite them together. Upon the open place left for the coals to be put in, are placed the rings that conftitute the ear. They first put into this open place the iron ring to fupport the clapper of the bell; then they make a round cake of clay, to fill up the diameter of the thickness of the core. This cake, after baking, is clapped upon the opening, and foldered with a thin mortar fpread over it, which binds the cover close to the core. The hollow of the model is filled with an earth, fufficiently moift to fix on the place, which is ftrewed at feveral times upon the cover of the core; and they beat it gently with a peftie, to a proper height; and a workman fmooths the earth at top with a wooden trowel dipped in water. Upon this cover, to be taken off afterwards, they affemble the hollows of the rings. When every thing is in its proper place, they itrengthen the outfide of the hollows with mortar, in order to bind them with the bridge, and keep them fteady at the bottom, by means of a cake of the fame mortar, which fils up the whole aperture of the fhell. This they let dre, that it may be removed without breaking, To make room for the metal, they pull off the hollows of the rings, through which the metal is to pafs, before it enters into the vacuity of the muld. The fhell being unloaded of its ear, they range under the mill-ftone five or fix pieces of wood, about two feet long, and thick enough to reach almoft the lower part of the fhell; between thefe and the mould, they drive in wooden wedges with a mallet, to thake the fhell of the model whereon it refts, fo as to be pulled up and got out of the pit. When this and the wax are resoved, they break the model and the layer of 3. FOUNDERY OF LETTERS, OR CASTING OF TYPES FOR PRINTING. In the bufinefs of cutting, cafting, &c. letters for printing, the letter-cutter must be provided with a vice, hand-vice, hammers, and files of all forts fuch as watch-makers ufe; alfo gravers and fculpters of all forts, ayd an oil-fione, &c. fuitable and fizeable to the feveral letters to be cut; a flat gauge made of box to hold a rod of fteel, or the body of a mould, &c. exactly perpendicular to the flat of the ufing file; a fliding gauge whofe ufe is to measure and let off diftances between the fhoulder and the tooth, and to mark off from the end, or from the edge of the work; a face gauge, which is a fquare notch cut with a file into the edge of a thin plate of fteel, iron or brafs, of the thickness of a piece of common tin, whofe ufe is to proportion the face of each fort of letter, viz. long letters, afcending letters, and fhort letters So there must be 3 gauges, and the guage for the long letters is the length of the whole body fuppofed to be divided into 42 equal parts. The gauge for the afcending letters Roman a: d Italic are five 7ths, or 30 parts of 42, and 33 parts for the English face. The gauge for the fort letters is three 7ths, or 18 parts of 42 of the whole body for the Roman and Italic, and 22 parts for the English face. The Italic and other ftanding gauges are to measure the scope of the Italic ftems, by applying the top and bottom of the gauge to the top and bottom lines of the jetters, and the other fide of the gauge to the fem; for when the letter complies with these three fides of the gauge, that letter has its true fhape. The next care of the letter-cutter is to prepare good feel punches, well tempered, and quite free from all veins of iron; on the face of which he draws or marks the exact shape of the letter with pen and ink if the letter be large, or with a smooth blunted point of a needle if it he finall; and then with fizeable and proper fhaped and pointed gravers and sculpters, digs or fculps out the teel between the ftrokes or marks he made on the face of the punch, and leaves the marks ftanding on the face. Having well shaped the infide ftrokes of his letter, he deepens the hollows with the fame tools; for if a letter be not deep in proportion to its width, it will, when used at prefs, print black, and be good for nothing. This work is generally regulated by the depth of the counter-punch. Then he works the outside with proper files till it be fit for the matrice. Before we proceed to the finking and juftifying of the matrices, we must provide a mould to justify them by. See Plate CLV. Fig. 13, and 14. Every mould is compofed of an upper and an under part. The under part is delineated in fig. 13. The upper part is marked fig. 14. and is in all refpects made like the under part, excepting the ftool behind, and the bow or fpring alfo behind; and excepting a fmall roundith wire between the body and carriage, uear the break, where the under part hath a fmall rounding groove made in the body. This wire, or rather half-wire, in the upper part makes the nick in the flank of the letter, when part of it is received into the groove in the under part. These two parts are fo exactly fitted and gauged into one another viz. the male-gauge marked e in fig. 14. into the female marked g in fig. 13.) that when the upper part of the mould is properly placed on, and in the under part of the mould, both together make the entire mould, and may be flid backwards for ufe fo far, till the edge of either of the bodies on the middle of either carriage comes juft to the edge of the female gauges cut in each carriage; and they may be flid forward fo far, till the bodies on either carriage touch each other: and the fliding of thefe two parts of the mould backwards makes the thank of the letter thicker, because the bodies in each part ftand wider afunder; and the fliding them forwards makes the fhank of the letter thinner, becaufe the bodies on tach part of the mould are as follow: viz. a, e carriage. b, The body. c, The male gauge de, The mouth-piece. f i, The regifter. g, The female gange. h, The bag. a aa a, The bottom plate. b bb, The wood on which the bottom piate lies. The mouth. d d, The throat, edd, The pallat. f, The nick. gg, The ftool, bb, The fpring or bow. Then the mould muft be juftified: and firft the founder juftifies the body, by cafting about 20 proofs or famples of letters; which are fet up in a compofing ftick, with all their nicks towards the right hand; and then by comparing thefe with the pattern letters, fet up in the fame manner, he finds the exact mea. fure of the body to be caft. He alfo tries if the two fides of the body are parallel, fo that the body be no bigger at the head than at the foot, by tating half the number of his proofs and turning them with their heads to the feet of the other half and if then the heads and the feet be found ex actly even upon each other, and neither to drive out nor get ia, the two fides may be pronounced parallel. He farther tries whether the two fides of the thickness of the letter be parallel, by fift fetting his proofs in the compofing stick with their nicks upwards, and then turning one half with their heads to the feet of the other half; and if the heads and feet lie exactly upon each other, and neither drive out nor get in, the two fides of the thickness are parallel. The mould thus juftified, the next butinefs is to prepare the matrices. A matrice is a piece of brafs or copper of about an inch and a half long, and of a thibknefs in proportion to the fize of the letter it is to contain. In this metal is funk the face of the letter intended to be caft, by ftriking the letter punch about the depth of an n. After this the fides and face of the matrice must be juftified, and cleared with files of all bunchings made by firking the punch. Every thing thus prepared, it is brought to the furnace; which is built of brick upright, with 4 fquare fides, and a ftone on the top, in which ftone is a wide round hole for the pan to ftand in. A foundery of any extent has feveral of thefe furnaces in it. As to the metal of which the types are to be caft, this, in extenfive founderies, is always prepared in large quantities; but caft into fmall bars, of about 20 pounds weight, to be delivered out to the workmen as occafion requires. In the letter foundery, which has been long carried on with reputation under the direction of Dr Alex. Wilfon and fons at Glasgow, we are informed, that a stock of metal is made up at two different times of the year, fufficient to serve the cafters at the furnace for fix months each time. For this purpofe, a large furnace is built under a fhade, furnished with a wheel vent, in order the more equally to heat the fides of a ftrong pot of caft iron, which holds when full 15 Cwt. of the metal. The fire being kindled below, the bars of lead are let foftly down into the pot, and their fufion promoted by throwing in fome pitch and tallow, which foon inflame. An outer chimney, which is built fo as to project about a foot over the fartheft lip of the pot, catches hold of the fame by a ftrong draught, and makes it act very powerfully in melting lead; whiift it ferves at the fame time to convey away all the fumes, &c. from. the workmen, to whom this laborious part of the bufinefs is committed. When the lead is tho roughly melted, a due proportion of the regu us or antimony and other ingredients are put in, and tome more tallow is enflamed to make the whole incorporate fooser. The workmen, having mix ed the contents of the pot very thoroughly by ftirring long with a large iron ladle next proceed to draw the metal off into the fmall troughs of caft iron, which are ranged to the number of 80 upon a leve platform faced with ftone, built towards the right hand. In the course of a day 15 Cwt. of metal can be easily prepared in this manner; and the operation is continued for as many days as are neceffary to prepare a stock of metal of all the various degrees of bardness. After this, the whole is difpofed into prefles according to its quality, to be delivered out occafionally to the workmen. |