I 

 274 TRANSACTIONS OF THE 



When burnt 100 parts yielded 2.12 per cent of ash, which con- 

 tained in 100 parts, 



Phosphoric acid, _•. 43.52 



Lime, _ 23.57 



Magnesia, 3.01 



Potash, .._ _ 17.23 



Soda, _ 1.19 



Common salt, 11.19 



The Peruvian guano contained in 100 parts. 



Water, 10.54 



Organic matter and ammoniacal salts, 2 1 .68 



Phosphates, 46.20 



Alkaline salts, 18.31 



Sand, 3.27 



Prof. Way observed that wheat contains about two per cent of 

 nitrogen, so do the sprats. One hundred lbs. of wheat require 

 about 1| lbs. of ash, of which about one half is phosphoric acid, 

 and one third potash. One hundred lbs. of sprats contain two 

 pounds of ash, of which two-fifths is phosphoric acid, and one fifth 

 potash. What manure (he asks) should be more fit to produce a 

 bushel of wheat than a half hundred lbs. of sprats 1 



PROGRESS OF AGRICULTURAL CHEMISTRY. 



We sometimes complain "how little has agricultural chemistry 

 really done for agriculture." 



We can better decide by looking back and then compare. — 

 " What is the food of plants ?" Going back eighty years and con- 

 sidering Arthur Young as the pioneer of his day — let us see ! in 

 comparison with the Rothamsted experiments what he knew. 



In 1783, '4 and '5, Young grew plants in pots containing vari- 

 ous soils — manured with various substances. One of his conclu- 

 sions was that common salt is a valuable manure, though never 

 proved before. His notes on this subject are interesting — " that 

 salt acted as a very good manure on loam, but did no good what- 

 ever on sand, which is remarkable, and should make us conjecture 

 that its operation is mechanical — salt rendering the loam much 



