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JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



suffer. Similarly, carbon-dioxide excreted by our lungs and 

 skin is injurious to us, and so on without limit. 



The organisms thrive and multiply around the absorbent 

 nodules, because these remove from the organisms the combined 

 nitrogen which is thrown off by their vital changes. Both are 

 thus benefited. This may be exemplified by the fact, if Clover 

 and Eye -grass be treated with manures rich in nitrogen, the 

 Clover dies out, perishing with the disappearance of its micro- 

 scopic food-provider, while the Rye-grass thrives abundantly, 

 because it has not only manure congenial to it, but also plenty 

 of room owing to the death of its companion. The importance 

 of this discovery to agriculture is immense. A Mr. Mason, on 

 the stiffest and most intractable Oxford clays, is growing Corn 

 at a profit, because he is taking advantage of this advanced fact, 

 now no secret, since it has been proclaimed in many scientific 

 journals. Mr. Mason proceeds thus : He manures his unpro- 

 mising soil with potash in the form of kainit and phosphorus in 

 the form of basic slag, with which he raises a crop, say, of Beans. 

 These, by means of the bacteria nodules on their roots, take their 

 combined nitrogen from the air. Eventually the Beans go to 

 market, while the remaining stems and roots are returned to the 

 soil as a green manure, thus giving it an abundance of nitrogen, 

 gained without cost, as well as the greater part of the purchased 

 potash and phosphorus. To discover what necessary consti- 

 tuent is present in sufficient quantity, in any soil, we may pro- 

 ceed thus : Take four pots, filling them with similar quantities 

 of the typical mould. Sow seeds in the pots, so as to secure abso- 

 lutely uniform conditions, manuring each as indicated below : — 



Nitrogen. Potash. Phosphorus. Thosphorus, Potash, 



Nitrogen. 



Using nitrate of soda in No. 1 ; basic slag, well mixed with the 

 soil, in No. 3 ; and kainit in No. 2 — No. 4 receiving all three. If 

 we find No. 2 gives us the finest results in a marked degree, we 

 learn that our soil demands potash ; if No. 3 is best, then 

 phosphorus is required ; if No. 4 is best of all, then all are 

 needed — the condition of Nos. 2 and 3 indicating the relative 



