rate of 225 and 400 Ibs. per acre, respectively. The Nitrate Food for 



of Soda was applied at the rate of 300 Ibs. per hectare (267 Plants 

 Ibs. per acre) and the inoculated soil at the rate of 6 cubic l8 ? 

 meters per hectare. 



Yields per Acre and Percentage Increase of Crops on Inoc- 

 ulated and Uninoculated Gravelly Soil. 



Atmospheric Fertilizers. 



No task which chemists have set for themselves in the 

 last few years has aimed to confer greater benefits on civilized 

 man than that of producing a cheap fertilizer from the air. 

 Nitrogen, which constitutes about four-fifths of the atmos- 

 phere, is one of the essentials of plant life, but vegetation is 

 singularly reluctant to draw directly on that magnificent store. 

 Very few crops which the farmer raises clover and alfalfa 

 are among them show much disposition to absorb free 

 Nitrogen. Only in such compounds as Nitrate of Soda (salt- 

 petre} and Nitrate of lime is the usefulness of the element 

 usually manifested, and the productiveness of the soil is in a 

 large measure determined by the quantity of these substances 

 present in it. If this has been reduced by drawing repeatedly 

 on the original supply, the land will yield less and less each 

 year until it has been freshly enriched. Other materials may 

 be employed as fertilizers, the choice being governed by the 

 soil to which it is proposed to minister, and reference also 

 being had to the crop which is next to be grown. Broadly 

 speaking, however, Nitrates may be regarded as the most 

 valuable of these agents and recent discoveries in Chili show 

 the supplies of nitrate of soda now in sight are practically in- 

 exhaustible. 



