Chapter C: D E F are the four printing cylinders, named in the order of their (28)

FLOSS-SILK (_Filoselle_, _Bourre de soie_, or _fleuret_, Fr.); is the name given to the portions of ravelled silk broken off in the filature of the cocoons, which is carded like cotton or wool, and spun into a soft coarse yarn or thread, for making bands, shawls, socks, and other common silk fabrics. The floss or fleuret, as first obtained, must be steeped in water, and then subjected to pressure, in order to extract the gummy matter, which renders it too harsh and short for the spinning wheel. After being dried it is made still more pliant by working a little oil into it with the hands. It is now ready to be submitted to the carding engine. See COTTON MANUFACTURE. It is spun upon the flax wheel.

The female peasants of Lombardy generally wear clothes of homespun floss silk. Of late years, by improved processes, pretty fine fabrics of this material have been produced both in England and France. M. Ajac, of Lyons, presented at one of the French national exhibitions of the objects of industry, a great variety of scarfs and square shawls, of _bourre de sole_, closely resembling those of _cachemere_.

FLOUR; the finely ground meal of wheat, and of any other corns or _cerealia_. See BREAD.

FLOUR OF WHEAT, _Adulterations of_, _to detect_.

The first method is by specific gravity. If potato flour be added, which is frequently done in France, since a vessel which contains one pound of wheat flour will contain one pound and a half of the fecula, the proportion of this adulteration may be easily estimated. If gypsum or ground bones be mixed with the flour, they will not only increase its density still more; but they will remain after burning away the meal.

The second method is by ascertaining the quantity of gluten which the suspected sample will afford, by the process prescribed under the article BREAD. The two following chemical criteria may also be employed.

1st. Nitric acid has the property of colouring wheat flour of a fine orange yellow, whereas it affects the colour neither of fecula nor starch.

2nd. Pure muriatic acid colours good wheat flour of a deep violet, but dissolves fecula or starch, and forms with it a light, colourless, viscous fluid, decomposable by alkalis. It may also be observed, that as fecula absorbs less water than flour, this affords a ready means of detection.

The adulteration with bean or pea flour may be detected by pouring boiling water upon it, which developes the peculiar smell of these two substances.

FLOWERS (_Fleurs_, Fr.; _Blumen_, Germ.) of benzoin, of sulphur, of zinc, &c., is the appellation given by the older chemists to such substances as were obtained in a pulverulent or rather minutely crystalline form by the process of sublimation.

FLOWERS, ARTIFICIAL, MANUFACTURE OF. The art of representing by flowers, leaves, plants, &c., vegetable nature in her ornamental productions, constitutes the business of the artificial florist. The Italians appear to have been the first people in Europe who excelled in the art of making artificial flowers; but of late years the French have been most ingenious in this branch of industry.

Ribbons folded in different forms and of different colours were originally employed for imitating flowers, by being attached to wire stems. This imitation soon gave way to that by feathers, which are more delicate in texture, and more capable of assuming a variety of flower-like figures. But a great difficulty was encountered in dyeing them with due vivacity. The savages of South America manufacture perfect feather flowers, derived from the brilliant plumage of their birds, which closely resemble the products of vegetation. The blossoms and leaves are admirable, while the colours never fade.

The Italians employ frequently the cocoons of the silkworm for this purpose; these take a brilliant dye, preserve their colour, and possess a transparent velvety appearance, suitable for petals. Of late years, the French have adopted the finest cambric for making petals, and the taffeta of Florence for the leaves. M. de Bernardière employs whalebone in very thin leaves for artificial flowers; and by bleaching and dyeing them of various hues, he has succeeded in making his imitations of nature to be very remarkable.

The colouring matters used in flower dyeing are the following:--

For red; carmine dissolved in a solution of salt of tartar.

For blue; indigo dissolved in sulphuric acid, diluted and neutralized in part by Spanish whitening.

For bright yellow; a solution of turmeric in spirit of wine. Cream of tartar brightens all these colours.

For violet; archil, and a blue bath.

For lilac; archil.

Some petals are made of velvet, and are coloured merely by the application of the finger dipped in the dye.

FLUATES, more properly _fluorides_ (Eng. and Fr.; _Flusssäure_, Germ.); compounds of fluorine and the metals; as fluor spar, for example, which consists of fluorine and calcium.

FLUOR SPAR. (_Chaux fluatée_, Fr.; _Spath fluor_, Germ.) This mineral often exhibits a variety of vivid colours. It crystallizes in the cubic system; with regular octahedral and tetrahedral cleavages; spec. grav. 3·1 to 3·2; scratches calc spar, but is scratched by a steel point; usually phosphorescent with heat; fusible at the blowpipe into an opaque bead; acted on by the acids, with disengagement of a vapour which corrodes glass; its solution affords precipitates with the oxalates, but not with ammonia. Its constituents are, fluorine, 48·13; calcium, 51·87 in 100.

Fluor spar occurs subordinate to metallic veins; as to those of lead, in Derbyshire; of tin, in Saxony and Bohemia; but it is found also in masses or veins, either in crystalline rocks, associated with quartz, heavy spar, &c., as in Auvergne, Forez, Vosges, Norberg in Sweden; Norway; Petersburg; near Hall; Gourock, in Scotland, &c.; or among secondary limestones, slates, and sandstones, in Derbyshire, Cumberland, Cornwall, and New Jersey. It exists also in the amygdaloids of Scotland, and in the volcanic products of Monte Somma at Vesuvius. The variously coloured specimens, called Derbyshire spar, are worked upon the turning lathe into vases and other ornamental objects.

FLUX, (Eng. and Fr.; _Fluss_, Germ.) signifies any substance capable of promoting the fusion of earths or metallic ores by heat. White flux is the residuum of the deflagration in a red hot crucible, of a mixture of two parts of nitre, and one of cream of tartar. It is in fact merely a carbonate of potash. Black flux is obtained when equal parts of nitre and tartar are deflagrated. It owes its colour to the carbonaceous matter of the tartaric acid, which remains unconsumed; the quantity of nitre being too small for that purpose. The presence of the charcoal renders this preparation a convenient flux for reducing calcined or oxidized ores to the metallic state. Limestone, fluor-spar, borax, and several earthy or metallic oxides are employed as fluxes in metallurgy.

FLY POWDER; the black coloured powder obtained by the spontaneous oxidizement of metallic arsenic in the air.

FODDER; is the name of a weight by which lead and some other metals are sold in this country. It varies in its amount in different parts of the kingdom; being in Northumberland estimated at 21 cwts., and in other counties 22, 23 or even more cwts.

FONDUS; is the name given by the French to a particular style of calico printing resembling the rainbow, in which the colours are graduated or melted (_fondus_) into one another, as in the prismatic spectrum. See PAPER HANGINGS, for a description of the process.

FORGE; (Eng. and Fr.; _Feuer_, Germ.) is the name either of the furnace, where wrought iron is hammered and fashioned with the aid of heat, or the great workshop where iron is made malleable. The former is called a smith’s forge, the latter a shingling mill. See IRON.

_Fig._ 466. represents a portable truck forge of a very commodious construction. A is the cylindric leather bellows, pressed down by a helical spring, and worked by means of the handle at B, which moves the horizontal shaft C, with its two attached semicircular levers and chains. D, is the pipe which conducts the blast to the nozzle at E. The hearth may be covered with a thin fire-tile or with cinders. F is a vice fixed to the strong rectangular frame. This apparatus answers all the ordinary purposes of a smith’s forge; and is peculiarly adapted to ships, and to the execution of engineering jobs upon railways, or in the country. The height is 2 feet 6 inches; the length is 2 feet 9 inches; the width 2 feet. Weight about 2 cwt.

FORMIATES; are compounds of formic acid, with the salifiable bases. Many of them are susceptible of crystallization.

FORMIC ACID; (_Acide Formique_, Fr.; _Ameisensäure_, Germ.) exists in the bodies of wood ants, associated with the malic or acid of apples. The artificial formation of this animal secretion, is one of the most remarkable triumphs of modern chemistry. If 10 parts of tartaric acid, 14 of black oxide of manganese, 15 of concentrated sulphuric acid, and from 20 to 30 of water be mixed and distilled in a retort, formic acid will be the liquid product; while carbonic acid will be disengaged. It may also be generated from other mixtures. This acid is transparent and colourless, of a pungent sour smell, a strongly acid taste, of specific gravity 1·1168 at 60° F., and may be re-distilled without suffering any change. It contains in its most concentrated form 19-3/4 per cent. of water. The dry acid, as it exists in the _formiates_, is composed of 32·54 carbon, 2·68 hydrogen, and 64·78 oxygen; or of two volumes carbonic oxide gas, and one volume of vapour of water. It reduces the oxides of mercury and silver to the metallic state. It has not hitherto been applied to any use in the arts.

FORMULÆ, CHEMICAL, are symbols representing the different substances, simple and compound.

+-------------------------+--------------------+---------+--------+
| Name. | Formula. | Oxygen |Hydrogen|
| | | = 100. | = 1. |
+-------------------------+--------------------+---------+--------+
|Oxygen |O | 100·000 | 16·026 |
|Hydrogen |H | 6·2398| 1·000 |
| |2H | 12·4796| 2·000 |
|Nitrogen |N | 88·518 | 14·186 |
| |2N | 177·086 | 28·372 |
|Phosphorus |P | 196·155 | 31·436 |
| |2P | 392·310 | 68·872 |
|Chlorine |Cl | 221·325 | 35·470 |
| |2Cl | 442·650 | 70·940 |
|Iodine |I | 768·781 |123·206 |
| |2I |1537·562 |246·412 |
|Carbon |C | 76·437 | 12·250 |
| |2C | 152·875 | 24·500 |
|Boron |B | 135·983 | 21·793 |
| |2B | 271·966 | 43·586 |
|Silicon |Si | 277·478 | 44·469 |
|Selenium |Se | 494·582 | 79·263 |
|Arsenic |As | 470·042 | 75·329 |
| |2As | 940·084 |150·659 |
|Chromium |Cr | 351·819 | 56·383 |
| |2Cr | 703·638 |112·766 |
|Molybdenum |Mo | 598·525 | 95·920 |
|Tungstenium |Tu or W |1183·200 |189·621 |
|Antimony |Sb | 806·452 |129·243 |
| |2Sb |1612·904 |258·486 |
|Tellurium |Te | 806·452 |129·243 |
|Tantalum |Ta |1153·715 |184·896 |
| |2Ta |2307·430 |369·792 |
|Titanium |Ti | 389·092 | 62·356 |
|Gold (aurum) |Au |1243·013 |199·207 |
| |2Au |2486·026 |398·415 |
|Platina |Pt |1215·220 |194·753 |
|Rhodium |R | 750·680 |120·305 |
| |2R |1501·360 |240·610 |
|Palladium |Pd | 714·618 |114·526 |
|Silver (argentum) |Ag |1351·607 |216·611 |
|Mercury (hydrargyrus) |Hg |1265·822 |202·863 |
| |2Hg |2531·645 |405·725 |
|Copper (cuprum) |Cu | 395·695 | 63·415 |
| |2Cu | 791·390 |126·829 |
|Uranium |U |2711·360 |434·527 |
| |2U |5422·720 |869·154 |
|Bismuth |Bi |1330·376 |213·208 |
| |2Bi |2660·752 |426·416 |
|Tin (stannum) |Sn | 735·294 |117·839 |
|Lead (plumbum) |Pb |1294·498 |207·458 |
| |2Pb |2588·996 |414·917 |
|Cadmium |Cd | 696·767 |111·665 |
|Zinc |Zn | 403·226 | 64·621 |
|Nickel |Ni | 369·675 | 59·245 |
|Cobalt |Co | 368·991 | 59·135 |
| |2Co | 737·982 |118·270 |
|Iron (ferrum) |Fe | 339·213 | 54·363 |
| |2Fe | 678·426 |108·725 |
|Manganese |Mn | 355·787 | 57·019 |
| |2Mn | 711·575 |114·038 |
|Cerium |Ce | 574·718 | 92·105 |
| |2Ce |1149·436 |184·210 |
|Zirconium |Zr | 420·238 | 67·348 |
| |2Zr | 840·476 |134·696 |
|Yttrium |Y | 401·840 | 64·395 |
|Beryllium (glucinum) |Be | 331·479 | 53·123 |
| |2Be | 662·958 |106·247 |
|Aluminum |Al | 171·167 | 27·431 |
| |2Al | 342·234 | 54·863 |
|Magnesium |Mg | 158·353 | 25·378 |
|Calcium |Ca | 256·019 | 41·030 |
|Strontium |Sr | 547·285 | 87·709 |
|Baryum |Ba | 856·88 |137·325 |
|Lithium |L | 127·757 | 20·474 |
|Natrium (sodium) |Na | 290·897 | 46·620 |
| |2Na | 581·794 | 93·239 |
|Kalium (potassium) |K | 489·916 | 78·515 |
|Ammonia |2N2H³ | 214·474 | 34·372 |
|Cyanogen |2NC | 329·911 | 52·872 |
|Sulphuretted hydrogen |2HS | 213·644 | 34·239 |
|Hydrochloric acid |2HCl | 455·129 | 72·940 |
|Hydrocyanic acid |2HNC | 342·390 | 54·872 |
| |. | | |
|Water |2H | 112·479 | 18·026 |
| |. | | |
|Protoxide of nitrogen |2N | 277·036 | 44·398 |
| |. | | |
|Deutoxide of nitrogen |N | 188·518 | 30·212 |
| |... | | |
|Nitrous acid |2N | 477·036 | 76·449 |
| |..... | | |
|Nitric acid | 2N | 677·036 |108·503 |
| |. | | |
|Hyposulphurous acid |S | 301·165 | 48·265 |
| |.. | | |
|Sulphurous acid |S | 401·165 | 64·291 |
| |..... | | |
|Hyposulphuric acid | 2S | 902·330 |144·609 |
| |... | | |
|Sulphuric acid | S | 501·165 | 80·317 |
| |..... | | |
|Phosphoric acid | 2P | 892·310 |143·003 |
| |..... | | |
|Chloric acid | 2Cl | 942·650 |151·071 |
| |...... | | |
|Perchloric acid | 2Cl |1042·650 |167·097 |
| |..... | | |
|Iodic acid | 2I |2037·562 |326·543 |
| |.. | | |
|Carbonic acid |C | 276·437 | 44·302 |
| |... | | |
|Oxalic acid |2C | 452·875 | 72·578 |
| |...... | | |
|Boracic acid | 2B | 871·966 |139·743 |
| |... | | |
|Silicic acid |Si | 577·478 | 92·548 |
| |.. | | |
|Selenic acid |Se | 694·582 |111·315 |
| |..... | | |
|Arsenic acid | 2As |1440·084 |230·790 |
| |... | | |
|Protoxide of chrome |2Cr |1003·638 |160·840 |
| |... | | |
|Chromic acid |Cr | 651·819 |104·462 |
| |... | | |
|Molybdic acid |Mo | 898·525 |143·999 |
| |... | | |
|Tungstic, or wolfram acid| W |1483·200 |237·700 |
| |... | | |
|Oxide of antimony |2Sb |1912·904 |306·565 |
| |.. | | |
|Antimonious acid |Sb |1006·452 |161·296 |
| |.... | | |
| |2Sb |2012·904 |322·591 |
| |..... | | |
|Antimonic acid |2Sb |2112·904 |338·617 |
| |.. | | |
|Oxide of tellurium |Te |1006·452 |161·296 |
| |... | | |
|Tantalic acid |2Ta |2607·430 |417·871 |
| |.. | | |
|Titanic acid |Ti | 589·092 | 94·409 |
| | . | | |
|Protoxide of gold |2Au |2586·026 |414·441 |
| |... | | |
|Peroxide of gold |2Au |2786·026 |446·493 |
| |.. | | |
|Oxide of platina |Pt |1415·220 |226·086 |
| |... | | |
|Oxide of rhodium |2R |1801·360 |228·689 |
| |. | | |
|Oxide of palladium |Pd | 814·618 |130·552 |
| |. | | |
|Oxide of silver |Ag |1451·607 |232·637 |
| | . | | |
|Protoxide of mercury |2Hg |2631·645 |421·752 |
| |. | | |
|Peroxide of mercury |Hg |1365·822 |218·889 |
| | . | | |
|Protoxide of copper |2Cu | 801·390 |142·856 |
| |. | | |
|Peroxide of copper |Cu | 495·695 | 79·441 |
| |. | | |
|Protoxide of uranium |U |2811·360 |450·553 |
| |... | | |
|Peroxide of uranium |2U |5722·720 |917·132 |
| |... | | |
|Oxide of bismuth |2Bi |2960·752 |474·49 |
| |. | | |
|Protoxide of tin |Sn | 835·294 |133·866 |
| |.. | | |
|Peroxide of tin |Sn | 935·294 |149·892 |
| |. | | |
|Oxide of lead |Pb |1394·498 |223·484 |
| |... | | |
|Minium |2Pb |2888·996 |462·995 |
| |.. | | |
|Brown oxide of lead |Pb |1494·498 |239·511 |
| |. | | |
|Oxide of cadmium |Cd | 796·767 |127·691 |
| |. | | |
|Oxide of zinc |Zn | 503·226 | 80·649 |
| |. | | |
|Oxide of nickel |Ni | 469·675 | 75·271 |
| |. | | |
|Oxide of cobalt |Co | 468·991 | 75·161 |
| |... | | |
|Peroxide of cobalt |2Co |1037·982 |166·349 |
| |. | | |
|Protoxide of iron |Fe | 439·213 | 70·389 |
| |... | | |
|Peroxide of iron |2Fe | 978·426 |156·804 |
| |. | | |
|Protoxide of manganese |Mn | 455·787 | 73·045 |
| |... | | |
|Oxide of manganese |2Mn |1011·575 |162·117 |
| |.. | | |
|Peroxide of manganese |Mn | 555·787 | 89·071 |
| |..... | | |
|Manganesic acid | 2Mn |1211·575 |194·169 |
| |. | | |
|Protoxide of cerium |Ce | 674·718 |108·132 |
| |... | | |
|Oxide of cerium |2Ce |1449·436 |232·289 |
| |... | | |
|Zirconia |2Zr |1140·476 |182·775 |
| |. | | |
|Yttria |Y | 501·840 | 80·425 |
| |... | | |
|Glucina, or berryllia |2Be | 962·958 |154·325 |
| |... | | |
|Alumina |2Al | 642·334 |109·942 |
| |. | | |
|Magnesia |Mg | 258·353 | 41·404 |
| |. | | |
|Lime |Ca | 356·019 | 57·056 |
| |. | | |
|Strontia |Sr | 647·285 |103·735 |
| |. | | |
|Baryta |Ba | 956·880 |153·351 |
| |. | | |
|Lithia |L | 227·757 | 36·501 |
| |. | | |
|Natron, or soda |Na | 390·897 | 62·646 |
| |... | | |
|Peroxide of sodium |2Na | 881·794 |141·318 |
| |. | | |
|Kali, or potassa |K | 589·916 | 94·541 |
| |... | | |
|Peroxide of potassium | K | 789·916 |126·593 |
| |. ... | | |
|Sulphate of potassa |K S |1091·081 |174·859 |
| |. ... | | |
|Protosulphate of iron |Fe S | 940·378 |150·706 |
| |... ... | | |
|Persulphate of iron |2Fe S³ |2481·906 |397·754 |
|Protochloride of iron |Fe 2Cl | 781·863 |125·303 |
|Perchloride of iron |2Fe 2Cl³ |2006·376 |321·545 |
|Protochloride of mercury |2Hg 2Cl |2974·295 |476·666 |
|Perchloride of mercury |Hg 2Cl |1708·472 |273·803 |
|Ferrocyanide of iron |Fe2NC + 2K2NC |2308·778 |370·008 |
| |. ... ... ... .| | |
|Alum |K S + 2AlS³ + 24 2H|5936·406 |951·378 |
| |. ... ... ... | | |
|Felspar |K Si + 2Al Si³ |3542·162 |567·673 |
+-------------------------+--------------------+---------+--------+

FOUNDING _of metals, chiefly of Iron._ The operations of an iron foundry consist in re-melting the pig-iron of the blast furnaces, and giving it an endless variety of forms, by casting it in moulds of different kinds, prepared in appropriate manners. Coke is the only kind of fuel employed to effect the fusion of the cast iron.

The essential parts of a well-mounted iron foundry, are,

1. Magazines for pig irons of different qualities, which are to be mixed in certain proportions, for producing castings of peculiar qualities; as also for coal, coke, sands, clay, powdered charcoal, and cow-hair for giving tenacity to the loam mouldings.

2. One or more coke ovens.

3. A workshop for preparing the patterns and materials of the moulds. It should contain small edge millstones for grinding and mixing the loam, and another mill for grinding coal and charcoal.

4. A vast area, called properly the foundry, in which the moulds are made and filled with the melted metal. These moulds are in general very heavy, consisting of two parts at least, which must be separated, turned upside down several times, and replaced very exactly upon one another. The casting is generally effected by means of large ladles or pots, in which the melted iron is transported from the cupola, where it is fused. Hence the foundry ought to be provided with cranes, having jibs movable in every direction.

5. A stove in which such moulds may be readily introduced, as require to be entirely deprived of humidity, and where a strong heat may be uniformly maintained.

6. Both blast and air furnaces, capable of melting speedily the quantity of cast-iron to be employed each day.

7. A blowing machine to urge the fusion in the furnaces.

_Fig._ 467. represents the general plan of a well-mounted foundry.

_a_, is a cupola furnace of which the section and view will be afterwards given; it is capable of containing 5 tons of cast-iron.

_a´_, is a similar furnace, but of smaller dimensions, for bringing down 1-3/4 tons.

_a´´_, is a furnace like the first, in reserve for great castings.

_b_, _b_, _b_, _b_, a vast foundry apartment, whose floor to a yard in depth, is formed of sand and charcoal powder, which have already been used for castings, and are ready for heaping up into a substratum, or to be scooped out when depth is wanted for the moulds. There are besides several cylindrical pits, from five to seven yards in depth, placed near the furnaces. They are lined with brick work, and are usually left full of moulding sand. They are emptied in order to receive large moulds, care being had that their top is always below the orifice from which the melted metal is tapped.

These moulds, and the ladles full of melted metal are lifted and transported by the arm of one or more men, when their weight is moderate; but if it be considerable, they are moved about by cranes whose vertical shafts are placed at _c_, _d_, _e_, in correspondence, so that they may upon occasion transfer the load from one to another. Each crane is composed principally of an upright shaft, embraced at top by a collet, and turning below upon a pivot in a step; next of a horizontal beam, stretched out from nearly the top of the former, with an oblique stay running downwards, like that of a gallows. The horizontal beam supports a movable carriage, to which the tackle is suspended for raising the weights. This carriage is made to glide backwards or forwards along the beam by means of a simple rack and pinion mechanism, whose long handle descends within reach of the workman’s hand.

By these arrangements in the play of the three cranes, masses weighing five tons may be transported and laid down with the greatest precision upon any point whatever in the interior of the three circles traced upon _fig._ 467. with the points _c_, _d_, _e_, as centres.

_c_, _d_, _e_, are the steps, upon which the upright shafts of the three cranes rest and turn. Each shaft is 16 feet high.

_f_, _f_, is the drying stove, having its floor upon a level with that of the foundry.

_f´_, _f´_, is a supplementary stove for small articles.

_g_, _g_, _g_, are the coaking ovens.

_h_, is the blowing machine or fan.

_i_, is the steam-engine, for driving the fan, the loam-edge stones,

_k_, and the charcoal mill.

_i´´_, are the boiler and the furnace of the engine.

_k´_, workshop for preparing the loam and other materials of moulding.

_l_, is the apartment for the patterns.

The pig-iron, coals, &c. are placed either under sheds or in the open air, round the above buildings; where are also a smith’s forge, a carpenter’s shop, and an apartment mounted with vices for chipping and rough cleaning the castings by chisels and files.

Such a foundry may be erected upon a square surface of about 80 yards in each side, and will be capable, by casting in the afternoon and evening of each day, partly in large and partly in small pieces, of turning out from 700 to 800 tons per annum, with an establishment of 100 operatives, including some moulding boys.

_Of making the Moulds._--1. Each mould ought to present the exact form of its object.

2. It should have such solidity that the melted metal may be poured into it, and fill it entirely without altering its shape in any point.

3. The air which occupies the vacant spaces in it, as well as the carburetted gases generated by the heat, must have a ready vent; for if they are but partially confined, they expand by the heat, and may crack, even blow up the moulds, or at any rate become dispersed through the metal, making it vesicular and unsound.

There are three distinct methods of making the moulds:--

1. In green sand; 2. In baked sand; 3. In loam.

To enumerate the different means employed to make every sort of mould exceeds the limits prescribed to this work. I shall merely indicate for each species of moulding, what is common to all the operations; and I shall then describe the fabrication of a few such moulds as appear most proper to give general views of this peculiar art.

_Moulding in green sand._--The name green is given to a mixture of the sand as it comes from its native bed, with about one twelfth its bulk of coal reduced to powder, and damped in such a manner as to form a porous compound, capable of preserving the forms of the objects impressed upon it. This sand ought to be slightly argillaceous, with particles not exceeding a pin’s head in size. When this mixture has once served for a mould, and been filled with metal, it cannot be employed again except for the coarsest castings, and is generally used for filling up the bottoms of fresh moulds.

For moulding any piece in green sand, an exact pattern of the object must be prepared in wood or metal; the latter being preferable, as not liable to warping, swelling, or shrinkage.

A couple of iron frames form a case or box, which serves as an envelope to the mould. Such boxes constitute an essential and very expensive part of the furniture of a foundry. It is a rectangular frame, without bottom or lid, whose two largest sides are united by a series of cross bars, parallel to each other, and placed from 6 to 8 inches apart.

The two halves of the box carry ears corresponding exactly with one another; of which one set is pierced with holes, but the other has points which enter truly into these holes, and may be made fast in them by cross pins or wedges, so that the pair becomes one solid body. Within this frame there is abundance of room for containing the pattern of the piece to be moulded with its encasing sand, which being rammed into the frame, is retained by friction against the lateral faces and cross bars of the mould.

When a mould is to be formed, a box of suitable dimensions is taken asunder, and each half, No. 1. and No. 2., is laid upon the floor of the foundry. Green sand is thrown with a shovel into No. 1. so as to fill it; when it is gently pressed in with a rammer. The object of this operation is to form a plane surface upon which to lay in the pattern with a slight degree of pressure, varying with its shape. No. 1. being covered with sand, the frame No. 2. is laid upon it, so as to form the box. No. 2. being now filled carefully with the green sand, the box is inverted, so as to place No. 1. uppermost, which is then detached and lifted off in a truly vertical position; carrying with it the body of sand formed at the commencement of the operation. The pattern remains imbedded in the sand of No. 2., which has been exactly moulded upon a great portion of its surface. The moulder condenses the sand in the parts nearest to the pattern, by sprinkling a little water upon it, and trimming the ill-shaped parts with small iron trowels of different kinds. He then dusts a little well-dried finely-sifted sand over all the visible surface of the pattern, and of the sand surrounding it; this is done to prevent adhesion when he replaces the frame No. 1.

He next destroys the preparatory smooth bed or area formed in this frame, covers the pattern with green sand, replaces the frame 1. upon 2. to reproduce the box, and proceeds to fill and ram No. 1., as he had previously done No. 2. The object of this operation is to obtain very exactly a concavity in the frame No. 1., having the shape of the part of the model impressed coarsely upon the surface formed at the beginning, and which was meant merely to support the pattern and the sand sprinkled over it, till it got imbedded in No. 2.

The two frames in their last position, along with their sand, may be compared to a box of which No. 1. is the lid, and whose interior is adjusted exactly upon the enclosed pattern.

If we open this box, and after taking out the pattern, close its two halves again, then pour in melted metal till it fill every void space, and become solid, we shall obviously attain the wished-for end, and produce a piece of cast iron similar to the pattern. But many precautions must still be taken before we can hit this point. We must first lead through the mass of sand in the frame No. 1., one or more channels for the introduction of the melted metal; and though one may suffice for this purpose, another must be made for letting the air escape. The metal is run in by several orifices at once, when the piece has considerable surface, but little thickness, so that it may reach the remotest points sufficiently hot and liquid.

The parts of the mould near the pattern must likewise be pierced with small holes, by means of wires traversing the whole body of the sand, in order to render the mould more porous, and to facilitate the escape of the air and the gases. Then, before lifting off the frame No. 1., we must tap the pattern slightly, otherwise the sand enclosing it would stick to it in several points, and the operation would not succeed. These gentle jolts are given by means of one or more pieces of iron wire which have been screwed vertically into the pattern before finally ramming the sand into the frame No. 1., or which enter merely into holes in the pattern. These pieces are sufficiently long to pass out through the sand when the box is filled; and it is upon their upper ends that the horizontal blows of the hammer are given; their force being regulated by the weight and magnitude of the pattern. These rods are then removed by drawing them straight out; after which the frame No. 1. may be lifted off smoothly from the pattern.

The pattern itself is taken out, by lifting it in all its parts at once, by means of screw pins adjusted at the moment. This manœuvre is executed, for large pieces, almost always by several men, who while they lift the pattern with one hand, strike it with the other with small repeated blows to detach the sand entirely, in which it is generally more engaged than it was in that of the frame No. 1. But in spite of all these precautions, there are always some degradations in one or other of the two parts of the mould; which are immediately repaired by the workman with damp sand, which he applies and presses gently with his trowel, so as to restore the injured forms.

Hitherto I have supposed all the sand rammed into the box to be of one kind; but from economy, the green sand is used only to form the portion of the mould next the pattern, in a stratum of about an inch thick; the rest of the surrounding space is filled with the sand of the floor which has been used in former castings. The interior layer round the pattern is called in this case, _new sand_.

It may happen that the pattern is too complex to be taken out without damaging the mould, by two frames alone; then 3 or more are mutually adjusted to form the box.

When the mould, taken asunder into two or more parts, has been properly repaired, its interior surface must be dusted over with wood charcoal reduced to a very fine powder, and tied up in a small linen bag, which is shaken by hand. The charcoal is thus sifted at the moment of application, and sticks to the whole surface which has been previously damped a little. It is afterwards polished with a fine trowel. Sometimes, in order to avoid using too much charcoal, the surfaces are finally dusted over with sand, very finely pulverized, from a bag like the charcoal. The two frames are now replaced with great exactness, made fast together by the ears, with wedged bolts laid truly level, or at the requisite slope, and loaded with considerable weights. When the casting is large, the charcoal dusting as well as that of fine sand, is suppressed. Every thing is now ready for the introduction of the fused metal.

_Moulding in baked or used sand._--The mechanical part of this process is the same as of the preceding. But when the castings are large, and especially if they are tall, the hydrostatic pressure of the melted metal upon the sides of the mould cannot be counteracted by the force of cohesion which the sand acquires by ramming. We must in that case adapt to each of these frames a solid side, pierced with numerous small holes to give issue to the gases. This does not form one body with the rest of the frame, but is attached extemporaneously to it by bars and wedged bolts. In general no ground coal is mixed with this sand. Whenever the mould is finished, it is transferred to the drying stove, where it may remain from 12 to 24 hours at most, till it be deprived of all its humidity. The sand is then said to be baked, or annealed. The experienced moulder knows how to mix the different sands placed at his disposal, so that the mass of the mould as it comes out of the stove, may preserve its form, and be sufficiently porous. Such moulds allow the gases to pass through them much more readily than those made of _green_ sand; and in general the castings they turn out are less vesicular, and smoother upon the surface. Sometimes in a large piece, the three kinds of moulding, that in green sand, in baked sand, and in loam, are combined to produce the best result.

_Moulding in loam._--This kind of work is executed from drawings of the pieces to be moulded, without being at the expense of making patterns. The mould is formed of a pasty mixture of clay, water, sand, and cow’s hair, or other cheap filamentous matter, kneaded together in what is called the loam mill. The proportions of the ingredients are varied to suit the nature of the casting. When the paste requires to be made very light, horse dung or chopped straw is added to it.

I shall illustrate the mode of fabricating loam moulds, by a simple case, such as that of a sugar pan. _Fig._ 468. is the pan. There is laid upon the floor of the foundry, an annular platform of cast-iron _a b_, _fig._ 469.; and upon its centre _c_, rests the lower extremity of a vertical shaft, adjusted so as to turn freely upon itself, while it makes a wooden pattern _e f_, _fig._ 470., describe a surface of revolution identical with the internal surface reversed of the boiler intended to be made. The outline _e g_, of the pattern is fashioned so as to describe the surface of the edge of the vessel. Upon the part _a d b d_, _fig._ 469., of the flat cast-iron ring, there must next be constructed, with bricks laid either flat or on their edge, and clay, a kind of dome, _h i k_, _fig._ 470., from two to four inches thick, according to the size and weight of the piece to be moulded. The external surface of the brick dome ought to be everywhere two inches distant at least, from the surface described by the arc _e_, _f_. Before building up the dome to the point _i_, coals are to be placed in its inside upon the floor, which may be afterwards kindled for drying the mould. The top is then formed, leaving at _i_, round the upright shaft of revolution, only a very small outlet. This aperture, as also some others left under the edges of the iron ring, enable the moulder to light the fire when it becomes necessary, and to graduate it so as to make it last long enough without needing more fuel, till the mould be quite finished and dry. The combustion should be always extremely slow.

Over the brick dome a pasty layer of loam is applied, and rounded with the mould _g e f_; this surface is then coated with a much smoother loam, by means of the concave edge of the same mould. Upon the latter surface, the inside of the sugar pan is cast; the line _e g_ having traced, in its revolution, a ledge _m_. The fire is now kindled, and as the surface of the mould becomes dry, it is painted over by a brush, with a mixture of water, charcoal powder, and a little clay, in order to prevent adhesion between the surface already dried and the coats of clay about to be applied to it. The board _g e f_ is now removed, and replaced by another, _g´ e´ f´_, _fig._ 471., whose edge _e´ f´_ describes the outer surface of the pan. Over the surface _e_, _f_, a layer of loam is applied, which is turned and polished so as to produce the surface of revolution _e´ f´_, as was done for the surface _e f_; only in the latter case, the line _e´ g´_ of the board does not form a new shoulder, but rubs lightly against _m_.

The layer of loam included between the two surfaces _e f_, _e´ f´_, is an exact representation of the sugar pan. When this layer is well dried by the heat of the interior fire, it must be painted like the former. The upright shaft is now removed, leaving the small vent hole through which it passed to promote the complete combustion of the coal. There must be now laid horizontally upon the ears of the platform _d d_, _fig._ 469., another annular platform _p q_, like the former, but a little larger, and without any cross-bar.

The relative position of these two platforms is shown in _fig._ 473. Upon the surface _e´ f´_, _fig._ 472., a new layer of loam is laid, two inches thick, of which the surface is smoothed by hand. Then upon the platform _p q_, _fig._ 473., a brick vault is constructed, whose inner surface is applied to the layer of loam. This contracts a strong adherence with the bricks which absorb a part of its moisture, while the coat of paint spread over the surface _e´ f´_, prevents it from sticking to the preceding layers of loam. The brick dome ought to be built solidly.

The whole mass is now to be thoroughly dried by the continuance of the fire, the draught of which is supported by a small vent left in the upper part of the new dome; and when all is properly dry, the two iron platforms are adjusted to each other by pin points, and _p q_ is lifted off, taking care to keep it in a horizontal position. Upon this platform are removed the last brick dome, and the layer of loam which had been applied next to it; the latter of which represents exactly by its inside the mould of the surface _e´ f´_, that is of the outside of the pan. The crust contained between _e f_ and _e´ f´_ is broken away, an operation easily done without injury to the surface _e f_, which represents exactly the inner surface of the pan; or only to the shoulder _m_, corresponding to the edge of the vessel. The top aperture through which the upright shaft passed must be now closed; only the one is kept open in the portion of the mould lifted off upon _p q_; because through this opening the melted metal is to be poured in the process of casting. The two platforms being replaced above each other very exactly, by means of the adjusting pin-points, the mould is completely formed, and ready for the reception of the metal.

When the object to be moulded presents more complicated forms than the one now chosen for the sake of illustration, it is always by analogous processes that the workman constructs his loam moulds, but his sagacity must hit upon modes of executing many things which at first sight appear to be scarcely possible. Thus, when the forms of the interior and exterior do not permit the mould to be separated in two pieces, it is divided into several, which are nicely fitted with adjusting pins. More than two cast-iron rings or platforms are sometimes necessary. When ovals or angular surfaces must be traced instead of those of revolution, no upright shaft is used, but wooden or cast-iron guides made on purpose, along which the pattern cut-out board is slid according to the drawing of the piece. Iron wires and claws are often interspersed through the brick work to give it cohesion. The core, kernel, or inner mould of a hollow casting is frequently fitted in when the outer shell is moulded. I shall illustrate this matter in the case of a gas-light retort, _fig._ 474. The core of the retort ought to have the form _e e e e_, and be very solid, since it cannot be fixed in the outer mould, for the casting, except in the part standing out of the retort towards _m m_. It must be modelled in loam, upon a piece of cast-iron called a _lantern_, made expressly for this purpose. The lantern is a cylinder or a truncated hollow cone of cast iron, about half an inch thick; and differently shaped for every different core. The surface is perforated with holes of about half an inch in diameter. It is mounted by means of iron cross bars, upon an iron axis, which traverses it in the direction of its length. _Fig._ 475. represents a horizontal section through the axis of the core; _g h_ is the axis of the lantern, figured itself at _i k k i_; _o i i o_ is a kind of disc or dish, perpendicular to the axis, open at _i i_, forming one piece with the lantern, whose circumference _o o_ presents a curve similar to the section of the core, made at right angles to its axis. We shall see presently the two uses for which this dish is intended. The axis _g h_ is laid upon two gudgeons, and handles are placed at each of its extremities, to facilitate the operation in making the core. Upon the whole surface of the lantern, from the point _h_ to the collet formed by the dish, a hay cord as thick as the finger is wound. Even two or more coils may be applied, as occasion requires, over which loam is spread to the exact form of the core, by applying with the hand a board, against the dish _o o_, with its edge cut out to the desired shape; as also against another dish, adjusted at the time towards _h_; while by means of the handles a rotatory movement is given to the whole apparatus.

The hay interposed between the lantern and the loam, which represents the crust of the core, aids the adhesion of the clay with the cast iron of the lantern, and gives passage to the holes in its surface, for the air to escape through in the casting.

When the core is finished, and has been put into the drying stove, the axis _g h_ is taken out, then the small opening which it leaves at the point _h_, is plugged with clay. This is done by supporting the core by the edges of the dish, in a vertical position. It is now ready to be introduced into the hollow mould of the piece.

This mould executed in baked sand consists of three pieces, two of which absolutely similar, are represented, _fig._ 476., at _p q_, the third is shown at _r s_. The two similar parts _p q_, present each the longitudinal half of the nearly cylindrical portion of the outer surface of the gas retort; so that when they are brought together, the cylinder is formed; _r s_ contains in its cavity the kind of hemisphere which forms the bottom of the retort. Hence, by adding this part of the mould to the end of the two others, the resulting apparatus presents in its interior, the exact mould of the outside of the retort; an empty cylindrical portion _t t_, whose axis is the same as that of the cylinder _u u_, and whose surface, if prolonged, would be every where distant from the surface _u u_, by a quantity equal to the desired thickness of the retort. The diameter of the cylinder _t t_ is precisely equal to that of the core, which is slightly conical, in order that it may enter easily into this aperture _t t_, and close it very exactly when it is introduced to the collet or neck.

The three parts of the mould and the core being prepared, the two pieces _p q_, must first be united, and supported in an upright position; then the core must be let down into the opening _t t_, _fig._ 477. When the plate or disc _o o_ of the core is supported upon the mould, we must see that the end of the core is every where equally distant from the edge of the external surface _u u_, and that it does not go too far beyond the line _q q_. Should there be an inaccuracy, we must correct it by slender iron slips placed under the edge of the disc _o o_; then by means of a cast iron cross, and screw bolts _v v_, we fix the core immovably. The whole apparatus is now set down upon _r s_, and we fix with screw bolts the plane surface _q q_ upon _r r_; then introduce the melted metal by an aperture _z_, which has been left at the upper part of the mould.

When, instead of the example now selected, the core of the piece to be cast must go beyond the mould of the external surface, as is the case with a pipe open at each end, the thing is more simple, because we may easily adjust and fix the core by its two ends.

In casting a retort, the metal is poured into the mould set upright. It is important to maintain this position in the two last examples of casting; for all the foreign matters which may soil the metal during its flow, as the sand, the charcoal, gases, scoriæ, being less dense than it, rise constantly to the surface. The hydrostatic pressure produced by a high gate, or filling-in aperture, contributes much to secure the soundness and solidity of the casting. This gate piece being superfluous, is knocked off almost immediately after, or even before the casting cools. Very long, and somewhat slender pieces, are usually cast in moulds set up obliquely to the horizon. As the metal shrinks in cooling, the mould should always be somewhat larger than the object intended to be cast. The iron founder reckons in general upon a linear shrinkage of a ninety-sixth part; that is one-eighth of an inch per foot.

_Melting of the cast-iron._--The metal is usually melted in a cupola furnace, of which the dimensions are very various. _Fig._ 478. represents in plan, section, and elevation, one of these furnaces of the largest size; being capable of founding 5 tons of cast-iron at a time. It is kindled by laying a few chips of wood upon its bottom, leaving the orifice _c_ open, and it is then filled up to the throat with coke. The fire is lit at _c_, and in a quarter or half an hour, when the body of fuel is sufficiently kindled, the tuyère blast is set in action. The flame issues then by the mouth as well as the orifice _c_, which has been left open on purpose to consolidate it by the heat. Without this precaution, the sides which are made up in argillaceous sand after each day’s work, would not present the necessary resistance. A quarter of an hour afterwards, the orifice _c_ is closed with a lump of moist clay, and sometimes, when the furnace is to contain a great body of melted metal, the clay is supported by means of a small plate of cast-iron fixed against the furnace. Before the blowing machine is set a going, the openings _g g g_ had been kept shut. Those of them wanted for the tuyères are opened in succession, beginning at the lowest, the tuyères being raised according as the level of the fused iron stands higher in the furnace. The same cupola may receive at a time from one to six tuyères, through which the wind is propelled by the centrifugal action of an excentric fan or ventilator. It does not appear to be ascertained whether there be any advantage in placing more than two tuyères facing each other upon opposite sides of the furnace. Their diameter at the nozzle varies from 3 to 5 inches. They are either cylindrical or slightly conical. A few minutes after the tuyères have begun to blow, when the coke sinks in the furnace, alternate charges of coke and pig iron must be thrown in. The metal begins to melt in about 20 minutes after its introduction; and successive charges are then made every 10 minutes nearly; each charge containing from 2 cwt. to 5 cwt. of iron, and a quantity proportional to the estimate given below. The amount of the charges varies of course with the size of the furnace, and the speed required for the operation. The pigs must be previously broken into pieces weighing at most 14 or 16 pounds. The vanes of the blowing fan make from 625 to 650 turns per minute. The two cupolas represented _fig._ 478., and another alongside in the plan, may easily melt 6-1/2 tons of metal in 2-3/4 hours; that is 2-1/3 tons per hour. This result is three or four times greater than what was formerly obtained in similar cupolas, when the blast was thrown in from small nozzles with cylinder bellows, moved by a steam engine of 10 horses power.

In the course of a year, a considerable foundry like that represented in the plan, _fig._ 467., will consume about 300 tons of coke in melting 1240 tons of cast iron; consisting of 940 tons of pigs of different qualities, and 300 tons of broken castings, gate-pieces, &c. Thus, it appears that 48 pounds of coke are consumed for melting every 2 cwt. of metal.

Somewhat less coke is consumed when the fusion is pushed more rapidly to collect a great body of melted metal, for casting heavy articles; and more is consumed when, as in making many small castings, the progress of the founding has to be slackened from time to time; otherwise, the metal would remain too long in a state of fusion, and probably become too cold to afford sharp impressions of the moulds.

It sometimes happens that in the same day, with the same furnace, pieces are to be cast containing several proportions of different kinds of iron; in which case, to prevent an intermixture with the preceding or following charges, a considerable bed of coke is interposed. Though there be thus a little waste of fuel, it is compensated by the improved adaptation of the castings to their specific objects. The founding generally begins at about 3 o’clock, P. M., and goes on till 6 or 8 o’clock. One founder, aided by four labourers for charging, &c., can manage two furnaces.

The following is the work of a well-managed foundry in Derby.

200 lbs. of coke are requisite to melt, or bring down (in the language of the founders), 1 ton of cast-iron, after the cupola has been brought to its proper heat, by the combustion in it of 9 baskets of coak, weighing by my trials, 40 pounds each, = 360 lbs.