98 ANNUAL OF SCIENTIFIC DISCOVERY. 



oil, say about 24,000 barrels of 42 gallons each. Much the larger 

 share of this is of inferior lard, made of mast-fed and still-fed hogs, 

 the material, to a great extent, coming from a distance ; hence the 

 poor quality of Western lard-oil. Lard-oil, besides being sold for 

 what it actually is, is also used for adulterating sperm-oil, and in 

 France serves to materially reduce the cost of olive-oil, the skill of 

 the French chemists enabling them to incorporate from 60 to 70 per 

 cent, of lard-oil with that of the olive. There is also an establish- 

 ment in that city which, besides putting up hams, &c., is extensive- 

 ly engaged in extracting the grease from the rest of the hog, and will 

 probably this year operate in this way on 30,000 hogs. It has seven 

 large circular tanks, six of capacity to hold each 15,000lbs., and one 

 6,000lbs. These receive the entire carcase, with the exception of 

 the hams, and the mass is subjected to steam-process, under a pres- 

 sure of 70lbs. to the square inch, the effect of which operation is to 

 reduce the whole to one consistency, and every bone to powder. The 

 fat is drawn off by cocks, and the residuum, a mere earthy sub- 

 stance, is taken away for manure. Besides the hogs which reach 

 this factory in entire carcases, the great mass of heads, ribs, back- 

 bones, tail-pieces, feet, and other trimmings of the hogs cut up at the 

 different pork-houses, are subjected to the same process, in order to 

 extract every particle of grease. This concern alone is expected to 

 turn out this season 3,600,000lbs. of lard, five sixths of which is 

 No. 1. Six hundred hogs daily pass through these tanks one day 

 with another. 



The stearine expressed from the lard is used to make candles by 

 being subjected to hydraulic pressure, by which three eighths of it is 

 discharged as an impure oleine ; this last is employed in the manufac- 

 ture of soap ; 3,000,000lbs. of stearine have been made in one year 

 into candles and soap in these factories, and they can make 6-OOOlbs. 

 of candles per average day throughout the year. Hunfs Merchants' 

 Magazine. 



ELASTIC MOULDS. 



THE art of making elastic moulds, for copying statuary, designs, &c., 

 has lately been introduced into the Sheffield (England,) School of Design. 

 It possesses great advantages over the old plan, as the moulds may 

 be made at small cost and with great rapidity. That which would oc- 

 cupy five or six days in the modelling, may be furnished by this pro- 

 cess in half that number of hours. By* the facility thus afforded, 

 beautiful forms may be multiplied so cheaply as to be brought within 

 the reach of all. The principal material used for the elastic moulds 

 is glue or gelatine. The best fish-glue will answer as well as gela- 

 tine, and is much cheaper. The material is dissolved, like glue, in a 

 vessel placed over the fire, in a pot of hot water, stirring it during 

 the process. To each pound of the gelatine it is necessary to add 

 three quarters of a pint of water, and half an ounce of beeswax. 

 It is ready for use when about the thickness of syrup. The model 

 must be oiled carefully with sweet oil, and the composition must be 

 poured upon it while warm, but not boiling. Having set, it may be 

 taken off the model. When the model is small, it, should be placed in 



