Fireproof.—(a) Fine river sand, 20 parts ; litharge, 2 parts ; quicklime, 1 part ; linseed oil, suffi cient to form a thin paste. Acquires a stony hardness. (b) Good clay, 2 parts ; sharp washed sand, 8 parts ; horse-dung, 1 part ; mixed thoroughly, and tempered like mortar. (c) Linse,ed, or almond meal, mixed to a paste with milk, lime-water, or starch-paste. Resists a temperature of 260° (500° F.). (d) Clay is puddled with water, and to it is added the greatest possible quantity of sand, which has been passed through a hair sieve ; the whole is worked up in the hands, and applied in coats more or less thick on vessels needing protection from the direct action of the fire.
Fireproof and Waterproof.—(a) Thoroughly dried and pulverized clay, 4 or 5 parts ; flue iron filinge, free flop. oxide, 2 parts ; peroxide of manganese, 1 part ; sea-salt, part ; borax, part; well mingled, aud rendered as hard as possible, then reduced to a thick paste with the neceesary quantity of water, and perfectly iucorporated. It must be applied immediately, aud, after appli cation, should be subjected to heat, gradually increasing almost to whiteness. (b) Sifted peroxide of manganese, 1 part ; pulverized zinc-white, 1 part ; commercial soluble glass, sufficient to form a thin paste. To be used immediately. These lutes become very hard, and present a complete resist ance to red heat and boiling water.
Glass, for.—(a) As a coating for glass vessels, to protect them from injury during exposure to fire, pipe-clay and horse-dung are made into a paste with water. This composition is applied by spreading it on paper ; it is used by pipe-makers, and will stand the extreme heat of their furnaces for twenty-four hours without damage. (b) Shredded tow, or plumbago, is substituted for the horse-dung.
Iron.—A lnte which is much used for closing the joints of iron pipes, and for similar purposes, is composed of the turnings or borings of cast iron, which must be clean and free from rust, mingled with varying proportions of sal-ammoniaa, flowers of sulphur, &c. For use, the mixture is stirred up with just enough water to thoroughly moiaten it ; and it is rammed or caulked into the joints with ordinary caulking tools, after which the joint is bolted together as tightly as possible. When the iron borings are very coarse, they are pounded down in an iron mortar, and the dust is aifted off before use. The various proportions employed are : —(a) Iron borings, 5 lb. ; sal ammoniac, in
powder, 2 oz. ; flowers of sulphur, 1 oz. ; water, sufficient to mix ; (b) Iron borings, 12 lb.; sal ammoniac, 2 oz.; sulphur, 1 oz. ; water, as in (a). (c) Iron borings, 7 to 8 lb.; sal-anamoniac, 2 oz. ; water, as before. (d) Iron borings, 4 lb.; good pipe-clay, 2 lb. ; powdered potsherds, 1 lb., made into a paste with salt and water. The formula (a) is that moat commonly used for ordinary purposes ; but formerly much more sulphur and sal-ammoniac were employed. The atrongeat lute, perhaps, is (c); but when the work is required to dry rapidly, as in the case of steam joints wanted in a hurry, the quantity of aal-ammoniac must be slightly increased, and a very little sulphur must be added. This addition causes quicker setting, but reduces the strength. The power of these lutea is dependent upon the oxidation and consequent expansion of the mass, there fore the leas foreign matters they contain, the better. They should be made up only as they are required, as they spoil rapidly ; when containing much sulphur, they may become quite 'hot in a few bours, and combustion has been known to take place in them when left together in quantity for a night. The formula (d) produces a lute that becomes very hard when allowed to dry alowly ; it is very suitable for repairing cracks in iron boilers, tanks, &c. (e) Finely sifted iron filings, 60 parts; finely powdered 88,1-ammoniac, 2 parts ; flowers of sulphur, 1 part. This powder is made into a paate with water, and immediately applied; it aoon sets as hard as the iron it is intended to lute.
Laboratory.—Thia lute is composed of equal parts of pitch, rosin, and thoroughly dried plaster of Paris. It is used for the masonry of chlorine chambers, sulphuric acid works, &c., aud as is lining for casks containing chloride of lime.
Mahogany, for.—(a) Beeswax, 4 oz., melted, and to it is added Indian red, 1 oz., and yellow ochre, sufficient to produce the required tint. (b) Shellac, melted and coloured as (a). These compounds aro used by cabinet-makers for filling up holes and cracka in mahogany furnitm.e.
Maissiat's.—Indiarubber melted, either with or without about 15 per cent. of either beeswax or tallow ; quicklime in fine powder is gradually added ; and the heat is continued, until change of odour allows that combination has taken place, and until a proper consistence is attained. It is used as a waterproof and airproof covering for maks.