ON ENDERING REALTHER, &C. WATER-PROOF. 131 



Animal Charcoal, in ^n impalpable powder, may be usefully ap- 

 plied as a facing to moulds for making iron or bronze castings : I 

 have also used it with success in cementing delicate pieces of iron, 

 to convert them into steel : it forms ivory-black, bone-black, &c. : 

 it is spread upon land, as a manure ; and assists in vegetation, even 

 after being used in the refineries, &c. It is employed, not only in 

 the preparation of sugar, but also to remove the color of various 

 ^tracts, whether sirupy or saline. [JDic/. Technologique. 



On rendering Leather, Canvass, Linen, ^c. Water-proof, 

 By MM. Farrimann and Thilly. 



To 100/6. of the best linseed oil are added I 1-2/6. of acetate of 

 lead, 1 1-4/6. of calcined unjber, 1 1-2/6. of white lead, and 1 1-2/6. 

 of very finely-powdered pumice-stone. These solid substances, 

 well grounded and mixed together, must be boiled in the oil for 

 ten hours, over a moderate fire, to prevent the oil from burning. 

 This varnish should be of such a consistence, that, when mixed 

 with a third part of its weight of pipe-clay, it should be as thick as 

 treacle. It is left to settle eight days, and is then to be passed 

 through a lawn seive. They then grind, in a solution of strong and 

 clear glue, as much pipe-clay as amounts in weight to the tenth 

 part of the oil employed, and mix to the consistence of ointment ; 

 adding the varnish by degrees, and stirring it well with a wooden 

 spatula. This varnish must be repeatedly stirred, till it becomes 

 perfectly fluid ; and then the desired tint is given by adding a 

 fourth part of the color, ground in oil. 



The linen must be stretched upon a wooden frame ; and the 

 composition applied upon it, with a large spatula 3 inches broad 

 and 9 inches long. The frame is then inverted, and the operation 

 repeated upon the other side of the cloth : it is then left to dry for 

 a week, and separated from the frame for use. 



This cloth may be used for riding-hoods, covers for carriages, 

 &;c. &c. 



For leather and skins, the same composition is used : but to give 

 the surface a smooth and brilliant appearance, the following var- 

 nish is employed : viz. 3/6. of the oil varnish, and an equal weight 

 of well-clarified resin, are boiled together, until the resin is dis- 

 solved ; they then add 2/6. of oil of turpentine, having the color 

 to be given to the varnish, ground with it, and passed through a 

 lawn sieve : this is to be applied with a brush. When the var- 

 nish is thoroughly dry, it must be rubbed even with a pumice- 

 stone and water, and be then washed clean. Two or three coats 

 of varnish being then applied, and each cpat suffered to dry for 

 two or three days, is su01cient to produce a brilliancy equal to that 

 of the Japan lacker. [Bullefln d\Fynconragcnie-!.t, A-'- 



