Marble, for.—Gum-lac ia coloured to imitate the marble on which it is used ; sometimes the gum is mixed with marble dust passed through a silken sieve. It is used for stopping up boles, cracks, and leakages in marble vessels.
Molu.'8.—Equal parts of pulverized brick and litharge are made into a paste with linseed oil. After application, a little fine sand is dusted over the lute, and it is dried in an oven.
Oxychloride.—Zine-whits is mixed with an equal volume of fine sand, and to it is added a slightly greater weight of a solution of ferrous chloride of zinc of 1.26 ap. gr. The whole is gronnd in a mortar, and the paste is applied to corks, after preasing them a little within the neck of the bottle.
Plastera.—(a) Plaster of Paris, baked and ground, acquires great hardness and solidity when left for twenty-four hours, in contact with a solution of alum, and when, after drying in the air, it is submitted to a second baking. (b) Still better reaults are obtained by employing an aqueous solu tion containing -a of borate and .6 of cream of tartar ; the plaster, baked and in fragments, is plunged into this solution until it ia saturated ; then it is calcined, and pulverized. (c) A mixture of silicate of potash, 100 parts ; carbonate of potash, 27 parts ; nnd water, 500 parts, may also he used.
Putty for Windows.—(a) A-mixture of boiled linseed oil, and whiting; (b) the whiting is some timea replaced by white-lead. (c) Linseed oil, 1 part ; fine sifted sand, 10 parts ; finely powdered litharge, 1 part ; Spanish-white, 2 pasta ; the linseed oil is boiled in an iron vessel, aud the sand and litharge are added in small portions at a time. After some minutea' ebullition, the fire is with drawn, and the maas is ground in a mill, with the gradual introduction of the Spanish-white. This lute will hold in wood, iron, and atone. Broken panea may be removed by passing the point of a hot iron over the joint.
Red-lead.—White-lead rubbed up with oil, 2 parts; red-lead, 1 part ; it is used for the joints of gas piping, steam engines, and of pumps.
Serbat.—Sulphate of lead, calcined and ground, 72 parts ; peroxide of manganese, 24 parts ; linseed oil, 13 parts ; intimatelrmixed. This lut,e is soft, and will remain in that state indefinitely. For use, it only needs to be rubbed np between the hands. It may be advantageously employed in boilers, steam enghaes, &c. ; it sets perfectly, and does not soften under the influence of heat, but, on the contrary, be,comes very hard, especially if care be taken to pass a hot iron over the joints. A sudden leak may be stopped immediately, by applying some of this lute under a hot iron. It is preferable to red-lead.
Steam Boilers and Pipes, for.—(a) Dried and powdered clay, 6 lb. ; iron filings, 1 lb.; made into a paste with boiled linseed oil ; used for stopping cracks and leaks in boilers, stoves, &e. (b)Litharge, in fine powder, 2 parte ; very flne sand, 1 part ; lime that has been allowed to slake spontaneously in a damp place, 1 part ; mixed, and kept from the air ; made into a paste with boiled oil, and used to mend cracks, and secure steam joints. (c) Good linseed-oil varnish ground with equal
weights of white-lead, oxide of manganese, and pipe-clay. (d) Dry, powdered clay, 1 part ; clean, sifted iron filings, 2 parts ; acetic acid, sufficient th make a paste. (e) Dry, powdered clay, 8 to 10 parts ; iron filings, free from rust, 4 parts; peroxide of manganese, 2 parts ; sea-salt, 1 part ; borax, 1 part ; water, sufficient to make a paste. (f) Sulphate of baryta, 1 part ; clay, 2 parts; made up with solutions of silicate of potash, and borax ; it resists a very high temperature. (q) Finely powdered graphite, 6 parts ; chalk, or slaked lime, 3 parts ; sulphate of baryta, 8 parts ; boiled linseed oil, 7 parts ; the solid substances are mixed dry, then ground, and made into a paste with the oil. (h) Iron filings, free from rust, 50 parts ; flowers of sulphur, 2 parts ; pulverized hydro chlorate of ammonia, 1 part ; these substances are mixed with water or urine, so as to make a solid and homogeneous paste, which is used in the joints of steam boilers. The lute swells, becomes very solid, and perfectly closes the joints. (i) Iron filings, 4 parts ; loam, 2 parts ; powdered sandstone, 1 part ; made into a paste with salt water ; becomes very hard on settiug. (j) A thick paste, com posed of silicate of soda and iron filings ; the latter substance may be replaced by a mixture, in equal parts, of powdered oxide of zinc and peroxide of manganese. (h) Sand, 84 parts ; Portland stone, 166 parts ; litharge, 18 parts ; pulverized glass, 0.90 parts : red-lead, 0.45 parts ; sub oxide of lead, 0.90 parts ; the whole rubbed up with oil.
Vulcanized Indiarubber.—For the joints of small vessels, such as tubes, especially those of glass or earthenware, vulcanized indiarubber tubing, slipped over the joint and tied on both sides, will last for a long time. Flat rings or washers of the same substance are also good for still heads, eze., where the parts can bo screwed up tightly.
Water-gutters, for.—Tar, 1 part ; tallow, I part ; fine brickdust, 1 part ; the latter is warmed over a very gentle fire ; the tallow is added, then the brickdust, and the whole is thoroughly mixed. It must be applied while hot.
Wood, Cracks in, for.—(a) Slaked lime, 1 part ; rye meal, 2 parts; made into a paste with a sufficient quantity of linseed oil ; (b) Glue, I part, dissolved in water, 16 parts ; when almost cold, sawdust and prepared chalk are stirred in to the required consistence ; (c) Oil varnish, thickened with &mixture of equal parts white-lead, red-lead, litharge, and chalk.
Wooden Vessels, for.—A mixture of lime, clay, and oxide of iron, separately calcined, and reduced to fine powder, then intimately mixed, kept in a close vessel, and made up with the requisite quantity of water when wanted.
Zino.—A solution of chloride of zinc at 50° to 60° Beaume, and powdered chloride of zinc, when mixed, combine to form the inaoluble oxychloride of zinc which solidifies into a bard, white mass. (See Alloys ; Asphalt ; Bones ; Pigments; Resinous Substances ; Varnishes ; Wax.)