1840.J SENATE— No. 36. 77 



vegetation is very minute is established by the effects produced, 

 beyond all question, by the application of even so small an 

 amount as half a bushel of the sulphate of lime or gypsum to 

 an acre. It is a wonderful fact, and sufficient to confound the 

 presumption of man in attempting to explain with confidence 

 many of the mysteries of nature, " that in experiments made 

 by Sir John Herschell, it was found that minute portions of 

 calcareous matter, in some instances less than the millionth part 

 of the whole compound, are sufficient to communicate sensible 

 mechanical motions and definite properties to the bodies with 

 which they are mixed."* 



The deficiency of lime in the soil is not, therefore, the cause 

 of the failure of the wheat crop among us. Proofs of this 

 might be multiplied, if there were occasion. Yet, on the other 

 hand, it will not be denied that the application of lime to some 

 soils, unless the application be to a much greater excess than is 

 likely to take place among us, produces a decided improvement. 

 I have no theory to establish on the subject ; and it cannot be 

 denied that even with professed chemists, the particular opera- 

 tion of lime upon the soil is as much matter of debate and 

 controversy, at this very time, in Scotland and in England, 

 where it has been for many years, and most extensively applied, 

 as any subject whatever connected with agriculture. Any so- 

 lution of the mode of operation of gypsum, or the sulphate of 

 lime, whose effects are often so astonishing, is not even ap- 

 proached. But I shall proceed to state some points which 

 seem to be well established in regard to lime. It has been 

 said that gypsum benefits vegetation by its attraction of mois- 

 ture from the atmosphere. It does indeed attract moisture, but 

 it holds it fast and does not give it out. Its effect on vegeta- 

 tion in this respect, therefore, must be the reverse of beneficial. 

 It has been supposed to assist the putrefaction or decomposition 

 of animal or vegetable substances. But this theory experiment 

 has wholly disproved. It has been supposed to form a necessary 

 food of plants ; and some portion of it is always obtained in the 



" Roget, Vol. II. p. 38. 



