32 



BOTANICAL GAZETTE 



[JULY 



essential constituents of these being present to the extent of 80 

 ppm., but the composition varies. The number of culture solu- 

 tions of the fertilizer salts used was 66, this being the number 

 requisite to obtain every possible ratio of P 2 O s , NH 3 , and K 2 0, m 

 10 per cent stages. The system employed, as well as all details 

 of preparation, was the same as already described in the similar 

 investigation with dihydroxystearic acid already mentioned. 



p 2 o s 



NMj 



Fig. 1. 



represent the 66 culture solutions. 



triangular diagram, with the points 



potassium 



m is used as a guide. In this diagram 

 c, 56, and 66, are the cultures which con- 

 , calcium acid phosphate, sodium nitrate, 

 respectively; that is, the total of 80 ppm. 



The line 



and NH 



NH\. or K 



mixtures of P*0 



in 10 per cent differences; 



2^5 



3 



cultures between 1 and 56 



