« ZurückWeiter »
end, which is afterwards supplied by a separate excel in chasing, as their numerous small ornapiece or cap. The cores of many of these Bir- ments used as decorations to chimney-pieces mingham brass-works are made to occupy so time-pieces, vases, &c. &c., fully demonstrate; much of the pattern, that the brass is not thicker many of which are in brass as well as in or than a shilling.
molu. Many of the brass-manufacturers who work Brass castings which are plain are cleaned up on a large scale, employ a steam-engine to punch for sale by being filed smooth or turned so by articles from sheet metal, from dies previously the turner, and afterwards polished by being formed. By this operation almost all the com- rubbed with emery till the surface becomes mon brass goods, (such as hand-plates to doors, regular and tolerably ever, after which they are roses to door and cabinet furniture, and many finished with tripoli. To keep brass works from light goods) are now made. The punched goods tarnishing and gettive; black, by exposure to the are very cheap, but of very little strength or du- air, the brass-workers have recourse to lacker rability, as may be noticed in many of the brass ing. This consists in covering the brass, moderarticles employed in our domestic economy. ately heated over a stove containing an open Brass mouldings, plain or wrought, are gene- charcoal fire, with a liquid, also moderately rally cast solid, and in moderate lengths; a pat- warm, composed of saffron and Spanish annotta, tern in wood, clay, or wax, is required, and the each iwo drams, put into a bottle with a pint of only precautions previously to founding them highly rectified spirits of wine, which when are, that they be carefully indented in the sand- together should be placed in a moderate heat table. If the mouldings be large and much and often shaken · from this a very strong tinccarved, a core may be used for these also, taking ture will be obtained, which must be afterwards care to leave the metal sufficiently thick to allow strained through a coarse linen cloth to take out of finishing up afterwards, without injuring the the dregs of the annotta and saffron ; it is then effect of the pattern.
to be returned to the bottle, and three ounces of All brass, as well as other foundings, require, seed-lac powdered must be added to it, and the when taken out of the sand, to be cleaner up whole again heated till the seed-lac be comand made complete; as they seldom come out pletely dissolved; after which it is fit for use, perfect. This is done in brass-founding, by file and will form a good and pale-colored lacker, ing off the cores, and filling up the small holes which will prevent the brass from changing with melted metal or solder. Some brass-works color by exposure to the air. It is laid on the are cast to a rough pattern, for instance, all those brass by a camel's-hair pencil as thin as it can which are cylindrical in shape; and such kind of be spread, and requires nothing to be done to it goods are put into a lathe and turned, and after it is so spread but a moderate rubbing. If smoothed up afterwards. Articles in brass which the brass be required to be of a redder color, are sculptured, are generally left in a mat-state increase the proportion of annotta in the lacker, on their grounds, and the raised parts burnished and it will be accomplished. All the best kinds up by hand; the mat-state refers to such parts of brass-works are gilt to prevent their changing only which are left without polish, or in a state color, and this constitutes the desideratum in in which the brass is found when it first comes the works in or molu. out of the sand, with the addition of cleaning The more important part of casting in brass and perfecting only.
consists in founding statues, busts, basso-relievos, The burnishing consists in making the raised vases, &c. The Greeks and Romans practised parts quite complete, and afterwards laying them it to an immense extent, as may be seen from down light upon a bench, or in a vice, whichever the vast number of statues and other works is most convenient; and working up the face of which have come down to us of both these the brass with a bent tool composed of a shaft people. The Greeks also formed most of those of steel, about half an inch wide and eight or instruments of brass, which we make of iron nine inches in length, fixed firmly in a handle and steel. Thus Homer describes the arms of wood. The end of the tool is turned up offensive and defensive, in his poems, as brazen. about a quarter of an inch, and ground away on He calls the Greeks by the general epithet of its inner edge. With this tool the workmen rub brass-coated, and seldom mentions steel. In the part to be heightened, as it is termed. They Herculaneum, Pompeii, Stabea, &c., were found have these heightening tools of various widths, many arms and instruments formed of brass or some one-eighth of an inch wide only, and others bronze, while very few of iron were discovered. as much as three-quarters of an inch. With Those of brass were adapted to the purposes of such tools they operate upon all the various sized agriculture, mechanics, mathematics, architecparts to be heightened ; and, as the part is thus ture, &c. In Pompeii was found a complete rubhed, the workman dips his tool in a lacker, set of surgeons' instruments formed of bronze, which is standing near him in an earthenware which shows that a preference was given to that dish. This lacker is commonly prepared from metal. turmeric dissolved in spirits of wine, and which In the founding of statues, busts, &c., three will be afterwards explained under the head of things in particular require attention : namely, lackering.
the mould, the wax, and shell or coat, the inner Chasing, or enchasing as it is called, is also mould or core, so called from being in the employed in brass works. It is a similar opera- middle or heart of the statue. In preparing tion to heightening, except that it is employed the core, the moulder is required to give it the in the more delicate works of sculpture to give attitude and contour of the figure intended to be them greater sharpness and effect. 'The French founded. The use of the core is to support the wax and shell, to lessen the weight, and save intended metal. To this coating or impression the metal. The core is made and raised on an is added a third, composed almost wholly of iron grate sufficiently strong to sustain it, and it dung, with a proportion of earth sufficient only is farther strengthened by bars or ribs of iron. to render it a little more tough and firm when The core is made of strong potter's-clay tem- used. When this is tolerably dry, the shell is pered with water, and mixed up with horse- finished by laying on several more coats or imdung and hair, all kneaded and incorporated pressions of the same composition, made strong together; with this it is modelled and fashioned and stiff by successive workings with the hand. previously to the sculptor's laying over it the When thi is finished, and
deemed adequate wax; some moulders use plaster of Paris and to support the heated metal, it is farther secured sifted brick-dust mixed together with water for and strengthened by several bands or hoops of their cores. The iron bars which support the iron, bound round it at about six inches from core are so adjusted, that they can be taken from each other, and fastened at bottom to the grate out of the figure after it is founded, and the on which the statue stands. Above the head of holes are restored by solder, &c.; but it is ne- the statue is made an iron circle for the purpose cessary in full-sized figures to leave some of the also of confining the shell and statue, to this iron bars affixed to the core to steady its project- circle the hoops are fastened at top. It may be ing parts. After the core is finished and got considered when the moulding has arrived at tolerably firm and dry, the operation of laying this state, to be in a condition to receive the on the waxen covering to represent the figure is melted metal; but it is not so exactly, as will performed, which must be all done, wrought soon appear. The mould, as bas been before and fashioned by the sculptor himself, and hy observed, is made upon an iron grate : under him adjusted to the core. Some sculptors work this grate is a furnace and flue, in which at this the wax separately, and afterwards dispose and period of the work a moderate fire is to be made, arrange it on the ribs of iron, filling up the and the aperture of communication therewith void spaces in the middle afterwards with liquid stopped up so as to keep in the heat. As the plaster and brick-dust, by which plan the core heat increases, and begins to operate on the is made as, or in proportion to, the sculptor's mould, preparation must be made to allow of progress in working the wax-model. Care the wax running freely from out of the shell: must be taken, however, in modelling the wax for this purpose, pipes are contrived at the base in both cases to make it of a uniform substance, of the mould, so that it may run gently off and in order to the metal being so in the work, of through these pipes. As soon as it is all run off, which the wax is its previous representative. the pipes are nicely stopped up with earth to When the waxen model is finished to the core, prevent the air entering them, &c. When this or adapted and filled afterwards, small tubes of is done, the shell is surrounded by any matter wax are fixed perpendicularly to it from top to that has non-conducting properties, for instance, bottom, to serve not only as jets to convey the pieces of brick put round and piled up of good melted metal to all parts of the work, but as thickness, secured by earth, will answer the vent-holes to allow a passage to the air gener- end; and the whole should be finally coated ated by the heated brass in flowing into the outside with loam as a farther protection to keep mould, and which, if not admitted readily to in the heat. escape, would occasion so much disorder in it After the shell is adequately surrounded with as would much injure the beauty of the work. materials to keep off the effect of the air, the Sculptors adjust the weight of the metal re- fire in the furnace is augmented, till such time quired in this kind of founding by the wax as both the matter surrounding the shell and it taken up in the model. One pound of wax so also become red-hot, and which in ordinary ciremployed will require ten pounds of metal to cumstances will take place in twenty-four hours' occupy its space in the casting. The work time; the fire is then extinguished, and the having advanced in progress so far, will now
whole allowed to cool: after which, the matter require covering with a shell. This consists of which has been packed round the shell is taken a kind of coat or crust laid over the wax, which, away, and its place occupied with earth moistbeing of a soft nature, easily takes and pre- ened and closely pressed to the mould in order serves the impression which it afterwards com- to make it more firm and steady. It will, when municates to the metal, upon its occupying the having advanced so far, be in a stale to receive place of the wax, which is between the shell the melted metal; to prepare which for the and core.
The shell is composed of clay and casting, a furnace is made a few feet above the white crucible dust, well ground, screened, and one employed to heat the mould: it is formed mixed up with water to the consistence of paint, like an oven, having three apertures, one of like which it is used. The moulder applies it which is for a vent, the other to admit the fuel, by laying it over the wax with a camel's-hair or and the last to let the melted metal flow through other soft pencil, which will require eight or and out of the furnace.
This last aperture nine times going over, allowing it time to dry should be kept very close whilst the metal is between each successive coat. After this coating fusing, when it has arrived at that state which is is firm upon the wax, and which is used only to deemed proper for running it into the shell, and protect it from those which are to follow, the which is known by the quick separation and recond part, or coating, is made up of common escape
of the zinc of the brass. A little tube is oarth, mixed with horse-dung: this is spread all laid to convey it into an earthenware basin, over the model, and in such thickness as to which is fixed over the top of the mould. Tato withstand, in some measure, the weight of the this basin all the large branches from the jeu enter, and from which is conveyed the metal when drying the core and melting the wax, is into all the parts of the mould. The jets are that which is more particularly sought for ; 10 all stopped up with a kind of plugs, which are do which, in the most effectual way, tour walls kept close till the basin which is to supply the of brick-work are built up round the model, in metal be full. When the furnace is first opened the middle of which is fixed the grate and furfor this purpose, the melted brass gushes for- nace; and on one side above is formed the mass ward like a torrent of fire, and is prevented of building intended for the furnace, which is to from entering any of the jets by the plugs, till be appropriated to the melting of the metal. the basin is sufficiently full to be ready to begin When the whole is finished and ready, a fire is with the mould, and which is esteemed so when made in the fire-place under the core of the the brass it contains is adequate to the supply of model, and kept up so as to produce a moderate all the jets at once, upon which occasion the heat to dry the core, and also to melt away the plugs from all of them are withdrawn. The wax from off it, which runs down by tubes as plugs consist of a long iron rod, with a head at has been before remarked upon, and indeed no one end capable of filling the whole diameter of difference whatever takes place in such founding, each tube. The hole in the furnace in which except everything being on a larger scale. the melted metal is contained, is opened with a When the wax is run off, and the fire extinguishlong piece of iron, fitted on the end of a pole to ed in the furnace, bricks are filled in at random, allow of the furnace-man keeping at a distance either into the hole, if founding under ground, from it, as many accidents occur by the red-hot or into the area between the walls if above metal coming in contact with the air, particu- ground; after this is done the fire in the furnace larly if it be damp, in which case the most is again lighted, and blown up and augmented, violent explosions take place. The basin is till such time as both the core and bricks are of alled almost in an instant after the furnace-plug a red-heat; when the fire is again extinguished, is withdrawn, and the metal is then let into the and the whole is left to cool; and when cooled several jets communicating with the model, the bricks are again removed, and all is cleared which when they have emptied themselves into away, and the space again occupied by moistthe shell or mould, the founding is finished, in ened earth to secure and steady the model. as far as the casting is concerned. The rest of the Nothing now remains but running in the metal, work is completed by the sculptor, who takes the which is performed as has been before described new brass figure from out of the mould and earth for smaller foundings of statues. in which it was encompassed, saws off the jets, All the principal cities of ancient Greece and and repairs and restores the parts where re- Rome, boasted of their wealth by enumerating quired. His tools for this purpose consist of their statues of brass. Athens, Delphi, and chisels of various sizes, gravers, puncheons, Rhodes, are each reported to have had in and files, &c.
about their temples 3000 brass statues. And In casting colossal statues a somewhat differ- Marcus Scaurus, though an edile only, adorned ent mode is pursued than the one already de- the circus at Rome with upwards of that numscribed : this arises wholly from the size, it being ber of statues of brass, during the time of the found difficult to remove the moulds of such celebrating of the Circensian shows. It afterworks; they are therefore worked and prepared wards, in consequence of this taste continuing to upon the spot where they are to be cast. There prevail at Rome, of forming and collecting are two ways of performing this. By the first works in brass, used to be a proverb among the plan a square bole is dug into the earth some- visitors of that celebrated city,' that in Rome what larger than would be required for the the people of brass were not less numerous than mould, and its sides are hemmed up with brick- the Roman people.' work : at its bottom is formed a hole below the BRONZE, by the Italians called Bronzo, was hottom of the one already prepared, as a fur- well known to the ancients. Egyptians, Greeks, nace, and which must be built up with brick-work, and Romans all made use of it, and that in most having an aperture made outwards into another cases to their important works as connected with pit prepared dear it, from which the fuel is put sculpture and the ornamental parts of architecinto the furnace. The top of the furnace in the ture. Bronze was selected by these people as first hole is covered by a grating of iron, and on bearing a finer edge, and not so likely as either this is moulded and placed the case of the statue of its component parts to oxydate by exposure to be cast, and also its waxen coating; in doing to the air: hence they made statues of it to which the same process is observed by the adorn the approaches to their cities and public sculptor as that already described. Near the edifices, affixed it in beautiful and highly relieved edge of the large pit, in which the model is ornaments to the friezes of their temples, cast it placed, is erected the furnace to melt the metal, in basso-relievos to represent the paraphernalia and which is similar to the one already described of their games and festivals, which were retained for common figure-casting, except being of in compartments about their works dedicated to larger dimensions ; it has like that three aper- their gods; and, finally, wrought it into baths, tures, one for putting in the wood, another for tripods, vases, lamps, and other purposes of vent, and a third to run the metal out at. By utility and ornament ; specimens of many of the second plan of founding colossal figures, it which have by its indestructibility come down to is thought sufficient to work the mould above us, as may be seen exhibited in the numerous ground, adopting the same mode with respect to public galleries on the continent, at Rome, a furnace and grate underneath it. For, whether Naples, Florence, and Paris, with some in our under ground or above it, to keep in the heat own Museum. Vol. IX.
all is clear, the shell is begun, the first layer of voids in the mould. The shell being thus unwhich is the same earth sifted very fine. While loaded of its rings, the mill-stone is arranged by it is tempering with water, it is mixed up with having placed under it five or six pieces of wool cow-hair to make it cohere; the whole, being a of about two feet long, and thick enough to reach third cullis, is gently poured on the model, and almost to the lower part of the shell; between fills exactly all the sinuosities of the figures; and these and the mould wooden wedges are driven, in this is repeated till the whole is two lines in order to shake the shell from off the model, so thickness upon the model ; when these layers are as to be pulled away and removed up out of the properly dried they cover it with a second of the pit. When this and the wax are removed, the same matter, but somewhat thicker than those model and layer of earth are arranged for the previously laid on; the compasses are now tried founding, as it is through these the melted metal and a fire is lighted in the core, so as lo melt off must pass into the hollows made by the rings. the wax of the inscription, &c.; after which the and which are between the shell and core. The layers of the shell are proceeded in by means of inside of the shell is last of all dried by burning the compasses. There is now to be added to the straw under it, this helps to smooth the surface composition a quantity of hemp, which is spread of the bell. The shell is put in the place so as upon the layers and afterwards smoothed upon to leave the same interval between it and the the board of the compasses.
The shell varies core as was before; and before the hollows of from four to five inches lower than the mill- the rings on the cap are put on again two vents stone before observed, but surrounds it quite are made, which are united to the rings, and also close, and prevents the extravasation of the me- to each other, by a mass of baked cement; after tal. The wax should be taken out before melt- which this mass of the cap is put on, the rings ing the metal. The case of the bell requires a and the vent over the bell are soldered to the cap separate work, which is done during the drying by cement; which is dried by gradual heat by of the several incrustations of the cements. It covering it with burning coals. So much having has seven rings; the last is called the bridge, been done, the pit surrounding the whole is filled and united to the others, it being a perpendicular up with earth, being pressed strongly all the time support to strengthen the curves.
It has an
of putting in close round the mould. aperture at its top to admit an iron peg and bent The furnace has a place for the fire and anoat its bottom, and this is introduced into two ther to contain the metal; the fire-place has a holes in the beam fastened with two strong iron large chimney with a spacious ash-hole. The keys. The rings are modelled with masses of furnace which contains the metal is vaulted, and beaten earth, that are dried in the fire in order its bottom is made of earth rammed down, the to have them hollow. The rings are gently rest is built of brick-work. It has four apertures, pressed upon a layer of earth and cow-hair to the first of which admits the flame projected by about one half of their depth, and then taken the fire to reverberate, the second is closed by a out, and care should be taken not to break the stopple, which is opened for the metal to run mould. This operation is repeated twelve times through; the other two are to separate the dross for twelve half moulds, that is, two and two and scoriæ by allowing the attendant of the furunited make the hollow of the six rings ; the nace to introduce a wooden rake through it for same is done for the hollow of the bridge. They the purpose. These apertures also pass the thick are all united together upon the open place left smoke. The ground or floor of the furnace is for the coals to be put into the oven. The rings built sloping for the metal to run down. When which are to form the ears are put first into this the metal is fused and ready to fill the shell, which open place, with the iron ring to support the should be examined minutely in every part to see clapper of the bell. After which a round cake if it be dry and ready to receive it; when all is of clay is make to fill up the diameter of the deemed ready, the metal is suffered to run into thickness of the core. This cake after having the shell by the apertures prepared to admit it, been baked is placed upon the opening, and fas- after which it is allowed to fix and cool. It is tened by a thin mortar spread over it, which then taken out, examined, and cleaned, in a sibinds the cover close to the core. The hollow milar manner to what has been before explained of the mould is filled with an earth sufficiently for brass and bronze castings. moist to fix itself on the place which is strewed The theory of the sound of bells is noticel in at several times upon the cover of the core; it is our article of that name; together with several then beaten gently with a pestle, and afterwards curious facts of their history. See Bell. smoothed.by a workman at top with a wooden The method of forming the profile of a bell, trowel dipped in water. Upon this cover, which previous to its being cast, in which the proporis afterwards to be taken off, is assembled the tion of the several parts may be seen, is as folhollow of the rings; and, when every thing is in lows : the thickness of the brim C1, of the diaits proper place, the outside of the hollows are gram, is the foundation of every other measure, strengthened with mortar, in order to bind and is divided into three equal parts. First, them to the bridge and keep them steady, and at draw the line HD, which represents the diameter the bottom by means of a cake of the same mor- of the bell; bisect it in F, and erect the perpentar, and which fills up the whole aperture of the dicular Ff; let D F and H F be also bisected shell. This is left to dry, that it may afterwards in E and G, and two other perpendiculars Ee, be removed without breaking. To make room Ga, be erected at F and G; G E will be the for the heated metal, the rings are taken out of diameter of the top or upper vase, i. e. the diathe hollows in the mould, as it is in these hol- meter of the top will be half that of the bell ; lows that the metal is to pass as it enters into the and it will, therefore, he the diameter of a bell
whicn will sound an octave to the other. Divide with the radius C1, describe the arc 1 pn; bithe diameter of the bell, or the line HD, into sect the part 1 2, of the line D n, and, erecting fifteen equal parts, and one of these will give Ci the perpendicular p m, this perpendicular will the thickness of the brim : divide again each of cut the arc 1pn in m, which terminates the these fifteen equal parts into three other equal rounding 1 p. Some founders make the bendparts, and then form a scale. From this scale ings, K, a third of a brim lower than the middle take twelve of the larger divisions or 2-15ths of of the line D N; others make the part C1 D the whole scale in the compass, and setting one more acute, and instead of making C1 perpenleg in D describe an arc to cut the line Ee in N; dicular to D N at 1, draw it out one-sixth of a draw N D, and divide this line into twelve equal brim higher, making it still equal to one brim; parts; at the point 1 erect the perpendicular so that the line 1 D is longer than the brim Ci. ic=10, and C 1 will be the thickness of the In order to trace out the top part, Na, take in brim=1-15th of the diameter; draw the line the compass eight divisions of the scale or eight CD; bisect DN; and at the point of the bisec- brims; and on the points N and D as centres, tion 6, erect the perpendicular 6 K=1} of the describe arcs to intersect each other in 8: on this larger divisions on the scale. With an opening point 8, with a radius of eight brims, describe the of the compass equal to twice the length of the arc N 6; this arc will be the exterior curve of the scale, or thirty brims, setting one leg in N, top or crown; on the same point 8 as a centre, describe an arc of a circle, and with the same and with a radius equal to 77 brims, describe leg in K, and the same opening, describe another the arc Ae, and this will be the interior curve of arc to intersect the former: on this point of the crown, and its whole thickness will be oneintersection as a centre, and, with a radius equal third of the brim. As the point 8 does not fall to thirty brims, describe the arc 'N K; in 6 K in the axis of the bell, a centre M may be found produced take KB= } of the larger measure of in the axis by describing, with the interval of the scale or one-third of the brim, and on the eight brims on the centres D and H, arcs which same centre with the radius 30f brims describe will intersect in M; and this point may be made an arc A B parallel to NK. For the arc BC, the centre of the inner and outer curves of the take twelve divisions of the scale or twelve brims crown as before. The thickness of the cap, which in the compass ; find a centre, and from that strengthens the crown at Q, is about one-third centre, with this opening, describe the arc BC, of the thickness of the brim; and the hollow in the same manner as N K or A B were described. branches or ears about one-sixth of the diameter There are various ways of describing the arc Kp, of the bell. The height of the bell is in proporsome describe it on a centre at the distance of tion to its diameter as twelve to fifteen, or in the nine brims from the points p and K; others, as proportion of the fundamental sound to its third it is done in the figure, on a centre at the dis- major; whence it follows that the sound of a bell tance only of seven brims from those points. is principally composed of the sound of its exBut it is necessary first to find the point p, tremity or brim, as a fundamental of the sound and to determine the rounding of the bell pi. of the crown which is an octave to it, and of that For this purpose, on the point C as a centre, and of the height which is a third.
Founétais less, adj. S visible on the earth. A
FOUND'LING, n. s. From found, of find. FOUNT, n. s.
Lat. fons; from fundo, A child exposed to chance; a child found without FOUN'TAIN, n. s.
to pour out, and signiany parent or owner.
fies the spring which is A piece of charity, practised by most of the nations Fount'FUL, adj. about us, is a provision for foundlings, or for those well; a spring; whether natural or artificial: a children who are exposed to the barbarity of cruel and jet; a spout of water: the head or first spring of unnatural parents.
Addison. water; hence, metaphorically, original; first prinThe goddess long had marked the child's distress, ciple; first cause. The adjectives are in direct And long had sought his sufferings to redress; opposition as to meaning. She prays the gods to take the foundling's part,
Unkindnesse past they gan of solace treat, To teach his hands some beneficial art.
And bathe in pleasaunce of the joyous shade,