336 COMMON SALT, NITRATE OF SODA, ETC. 



of soda is augmented by the addition of common salt, tlie 

 operation of the three salts essentially depends upon their 

 power of diffusing the nutritive substances present in the 

 "Soil, or of preparing those substances for absorption. In 

 what manner this takes place with all is not yet explained. 

 The first trustworthy experiments in this direction were 

 made by F. Kiihlmann (' Annal de Chim.' 3 ser. t. xx., 

 p. 279). Li the year 1845 he manured a natural meadow 

 with sal ammoniac, sulphate of ammonia, and common 

 salt ; and obtained the following quantities of hay : — 



Crop ofhai/, per hectare, 1845 and 1846. 



Increased crop 



Unmanured 11263 kilos, — 



Sal ammoniac, yearly 200 kilos, . 1496'1 „ 3700 kilos. 



Commo'isalt l foS : } ' 16950 „ 5687 „ 



Another meadow yielded : — 



Crop of haij, per hectare, 1846, 



Increased crop 



Unmanured 3323 kilos. — 



Sulphate of ammonia 200 kilos. . 5856 „ 2533 kilos. 



Common salt ". ?33 "„ } ' ^^^B „ 3173 „ 



For the purpose of examining the effect of common 

 salt upon cereals, the General Committee of the Agricul- 

 tural Society m Bavaria instituted at Bogenhausen and 

 Weihenstephan, in the years 1857 and 1858, a series of 

 experiments, conducted thus ; of two plots, the one was 

 manured with salts of ammonia, the other with the same 

 quantity of salts of ammonia and an addition of 3080 

 grammes of common salt. These experiments were 

 described at page 302, and it will be sufficient here to 

 quote -the crops which were obtained ^vith salts of am- 

 monia alone, and with common salt added to salts of 

 ammonia. 



