200 THE COMPLETE FARMER 



that most cultivated soils contain it in sufficient quantities 

 for the use of the grasses. In the common course of culti- 

 vation gypsum is furnished in the manure ; for it is con- 

 tamed in stable dung, and in the dung of cattle fed on grass. 

 Lord Dundas informs me, that having tried gj-psum without 

 any benefit on two of his estates in Yorkshire, he was in- 

 duced to have the soil examined for gypsum, and this sub- 

 stance was found in both soils. "^ 



It has been made a question whether burning and calcin- 

 ing gypsum make any difference with regard to its fertilizing 

 properties. This is said to be the practice among French 

 cultivators, and was likewise recommended by Dr. Deane. 

 But an English writer on agriculture observes that ' calcin- 

 ing is not likely to make any difference, because the sulphu- 

 ric acid in gypsum cannot be expelled by the most violent 

 heat of the furnace ; and an experiment of Arthur Young 

 countenances the assertion that the effects of gypsum are the 

 same, whether calcined or rough.' 



Dr. Joseph E. Muse, of Maryland, in an essay on the sub- 

 ject of gypsum, and its mode of operation, published in the 

 American Farmer, vol. i. p. 338, gives it as his opinion 

 ' that the chief, if not the only cause of the efficacy of gyp- 

 sum in promoting vegetation, is to be found in its tendency 

 to become phosphoric, and produced many facts and deduc- 

 tions therefrom, to show that gypsum by exposure to the at- 

 mosphere becomes phosphoric ; and that phosphorus exists 

 in vegetables. 



The late Dr. Gorham, in a paper read before a society in 

 Boston, and published in the New England Farmer, vol. v. 

 page 153, observed, ' When plaster of Paris is applied to the 

 seed it stimulates the little root, the action of the vessels is 

 thus increased, absorption goes on more rapidly, and it ac- 

 quires more nourishment for a given time than in ordinary 

 circumstances ; the consequences are a quick growth and 

 enlargement of the organs.' 



Colonel Taylor, of Virginia, observed, in substance, that 

 he sows of plaster from three pecks to one bushel to the 

 acre. Sown on clover in the spring, it benefits it considera- 

 bly. The best w^ay of using it is in the spring upon the 

 long manure of the preceding winter, to be ploughed in with 

 it. He thinks it a valuable ally, but by no means a substi- 

 tute for manure. That there should be intervals of two, 

 three, or four years between applying it to the same land. 



* Elements of Agricultural Chemistry, lecture vii. 



