358 TRANSACTIONS OF THE 



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farmers in the vicinity of Lyons, in France, use dilute oil of vitriol, 40 

 pounds to 200 gallons of veater, on their clovers, instead of plaster, and 

 produce precisely the same effect as attends its use. 



Dr. Home, of Edinburgh, in 1756, observed that sulphate of soda pro- 

 duced a remarkable effect upon several of the grasses, which fact has been 

 lost sight of by practical agriculturalists. It also contains sulphuric acid, 

 and may possibly succeed, where plaster fails. In many parts of our 

 country gypsum is the universal fertilizer for grass, corn and root crops. 

 Franklin wrote on its effects, and, I think, practically demonstrated them. 



Among the most bitter enemies of the use of gypsum were the proprie- 

 tors of salt pans, who declared that it was absolutely incompetent to 

 replace schlot, or the refuse of their pans, as an enricher ; but it has since 

 turned out that schlot is neither more nor less than sulphate of lime. 

 Experience has, however, taught us that gypsum alone is inadequate to 

 cause fertility without the concurrence of organic manures, and that it 

 produces its best effects upon sainfoin, lucern, and clover. I have found 

 it perfectly useless on natural grasses ; of doubtful advantage on turnips 

 and potatoes ; of no use on cereal grains, and perfectly null on low, damp 

 grounds. The French government ordered M. Bose to make a particular 

 enquiry on the subject of its use in agriculture, and he asked practical 

 men the following series of questions : 



1st. Does plaster act favorably on artificial meadows ? Of 4S opinions 

 given. 40 are in the affirmative, 3 in the negative. 



2d. Does it act favorably on artificial meadows, the soil of which is very 

 damp ? Unanimously, no. 



3d. Will it supply the place of organic manure, or of vegetable mould ' 

 Unanimously, no, 



4th. Will a barren soil be converted into a fertile one by the use of 

 plaster ? Unanimously, no. 



5th. Does gypsing sensibly increase the crops of the cereals 1 Of 32 

 opinions given, 30 were negative, 2 affirmative. 



In the above single lines from practical men, a summary of, perhaps, 

 forty years experience may be found. 



Professor Liebig says that a single pound of plaster, once converted into 

 sulphate of ammonia, would introduce into the soil a quantity of ammonia 

 equivalent to that which would be afforded it by 6.250 pounds of horse's 

 liquid, and that four pounds of gypsum increases the produce of a meadow 

 100 lbs. lie says that it decomposes slowly, and thus accounts for one 

 dressing lasting several years. 



If the farmer cannot obtain plaster of Paris for his clover leys, he may 

 use coal ashes at the rate of forty-five bushels to the acre, which will yield 

 as much sulphuric acid as 5.^- bushels of gypsum. These ashes contain 

 about 10^ per cent of sulphate of lime, and 10^ per cent of sand and lime. 

 Their effect will be found immediate on lucern and clover. They invari- 

 ably render a clay soil permeable, mechanically, and disintegrate it suffi- 

 ciently to admit atmospheric gases, besides affording the requisite amount 



