1846.] Duties of Agricultural Societies, etc. 45 



But precedent here fails to be a guide, because every successive 

 crop changes more or less the composition of the soil; hence we 

 may consider it an established fact, that a correct knowledge of 

 the composition of soils and vegetables is as important to the judi- 

 cious farmer, as a knowledge of law is to the lawyer. But how are 

 our farmers to obtain this knowledge? If they search agricultural 

 books and periodicals, they will find the composition of every ve- 

 getable substance to be stated differently as the result of every 

 new analysis. See the following for instance, in regard to the 

 composition of red clover: 



Horsford states 100 parts of the ash of red clover to contain, 

 of potash, 12.16: soda, 30.75: lime, 16.55. 



Johnson states it to contain, of potash, 24.80: soda, 4.20: lime, 

 2.41. 



And still another author gives it as follows: potash, 16.40: 

 soda, 4.00: lime, 22.40. 



Again, compare the following statements of the quantity of ash 

 left after burning a given quantity of the different species of 

 grains. The first column is quoted from the 53d page of the first 

 volume of American Quart. Jour, of Agriculture and Science; the 

 second from Boussingault; and the third from Weignan and Pals- 

 torff: 



Jsh in 100 lbs. of jSsh in 100 lb$. of Ash in 100 lbs. of 



Wheat, 1.18 Wheat, 2.40 



Wheat straw, .. 3.51 Wheat straw, . . 7.00 



Rye, 1.04 Rye, 2.30 



R>e straw, 2.79 Rye straw, 3.60 



Oats, 2.58 Oats 4.00 Oats, 2.86 



Oat; straw, 5.74 Oat straw, 5.10 



Here we have three w^riters who make the amount of potash 

 contained in the ash of red clover vary from 12 to 24 per cent; 

 the amount of soda from 4 to 30 per cent; and that of lime from 

 2 to 22 per cent; while the amount of ash derived from a given 

 quantity of grain or grass is equally various, as seen in the table. 



Further quotations might be made to illustrate this point, but 

 enough has been adduced to show that no positive knowledge can 

 be obtained from books, concerning the exact composition of 



