Foreign Literature and Science. 193 
4. 'To show the effects of various acids on copper plates, 
both pure and mixed and of different degrees of strength. 
Fifteen hundred Francs. 
5. For the fabrication of Russian Leather.—T here is rea- 
son to believe that the pyrolignous acid derived from astrin- 
gent bark, may be very advantageously used in this process. 
It appears evident from the writings of Pallas, and others 
that Whey, and Tannin derived from the bark of the 
willow or the leaves of the Statece Limonium and the oil of 
birch bark and the smoke of the branches of that tree are 
constantly employed in the process followed in Russia. 
Two premiums, one of three thousand and the other of 
fifteen hundred francs are offered for the two best specimens 
of leather of cow, veal, sheep or horse skin, (one of each 
kind) prepared with pyrolignous acid, as it issues from the 
wood, or after the separation of its constituent parts. 
6. For the discovery of a metal or an alloy of metals, 
much less oxidable than iron and steel, and suitable to be 
employed in instruments for dividing soft animal and vegeta- 
ble substances, used as food in domestic economy in many 
of the rural arts. Instruments used for pounding, cutting, 
rasping, grating, &c. are those alluded to; and of which iron 
and steel from their great liability to rust are often very ob- 
jectionable. Three thousand francs. 
ECONOMICAL ARTS. 
7. For the discovery of a substance which can be mould- 
ed like plaster and capable of resisting the air as well as 
stone. Two hundred francs. 
8. For the preservation of meats by drying. Five thou- 
sand francs. 
9. For the discovery of a vegetable substance, either 
natural or prepared, which may be substituted with advan- 
tage for mulberry leaves in the feeding of silk worms. ‘Two 
thousand francs. 
10. For the best elementary and practical iustruction 
upon the art of sounding or boring for water, so as to deter- 
mine the existence of sufficient and permanent springs. 
Two premiums of three thousand and of fifteen hundred 
francs. 
11. For the best cultivation of oleaginous plants. Twelve 
hundred francs. 
Vor. IV.....No. 1. 25 
