246 BOARD OF AGRICULTURE. 



« 



Natural Laws of Husbandry," abandoned it, and stated that 

 " the whole matter is still involved in doubt." 



It may not be worth while to add another theory to the many 

 already advanced, but I cannot well help saying, tliat experi- 

 ment and observation lead to the conclusion, that to neither the 

 salt in itself, or to the separated lime or acid, is its fertilizing 

 influence wholly or uniformly due. Its effects are nitrogenous 

 in some cases. It is capable of furnishing nitrogen to plants, 

 through the agency of an ammoniacal salt, resulting from its 

 soil decomposition. 



My attention was drawn to the salt accidentally, by observing 

 a strong smell of sulph-hydric acid, in a mass, at the door of a 

 plaster-mill. This had been trodden upon constantly, and water 

 and mud containing organic matter was solidly impacted with 

 it. Upon examination of a heap in the mill, I found that 

 masses, lying against wet timbers, evolved the same odor. This 

 led to experiment, and it was proved that gypsum in the pres- 

 ence of organic matter, is readily deprived of its oxygen, and 

 converted into sulphide of calcium. 



It was further proved, that this salt is capable of absorbing 

 ammonia from the air, and from decomposing vegetable matter, 

 and being thereby changed into hydro-sulphide of ammonia ; 

 and this again may be changed into carbonate of ammonia by 

 absorption of carbonic acid from the air. These are some of 

 the changes which sulphate of lime is proved capable of under- 

 going. But this is not the time or place, to protract the discus- 

 sion. It seems to me probable, that the different theorists, may 

 be partly -right and partly wrong; in short, that the salt is 

 capable of exerting specific influence in several ways, according 

 to the conditions under which it is acted upon. It may furnish 

 nitrogen, or lime, or sulphur, or it may act on some soils physi- 

 cally, and not chemically, by absorption of moisture. If these 

 views are correct, they may account for the doubt and confusion 

 under which the question rests. 



In all experiments with gypsum which have passed under my 

 observation, the lands or soils, upon which its best effects are 

 observed, are hilly pastures, with a northern aspect and a moist, 

 moss-covered soil. Mossy meadows are greatly improved under 

 its use. 



