THE LEAD ARSENATES. 



17 



Peach. — The results of the experiments on the peach are, on the whole, 

 very similar to those obtained from the plum. In general, the safety lines 

 are very close, and the conclusion reached that the jjlum is somewhat more 

 resistant than the peach is based mainly upon experiments with other 

 arsenicals. There seems to be less difference at the T and H limits of the 

 charts than was shown for the plum. In three sets of tests (Figs. 19, 20 and 

 21) the clear and cloudy weather lines cross, but the difference is not very 

 great. The neutral arsenate fails to make quite as good a showing as with 



//umiditu. 



70 -^ 



B V? 



Fig. 22. — Peach — Safety Lines for All Lead Arsenates. AB, 

 safety line tor spraying with any reliable lead arsenate under all 

 weather conditions; 1, pure acid paste, clear weather; 2, neutral 

 lead arsenate, cloudy weather; 3, pure acid paste, cloudy weather; 

 4, neutral lead arsenate, clear weather; 5, commercial acid paste, 

 clear weather; 6, commercial acid powder, clear weather; 7, same, 

 cloudy weather; 8, commercial acid paste, cloudy weather. 



the other trees, but is, nevertheless, still the best for the greater part of its 

 range. "Elbowing" of the safety lines is again in evidence except with 

 the neutral arsenate and the commercial acid paste in cloudy weather. 

 Perhaps in this last case a larger number of tests (it was not possible to 

 make very many) might change the path of this line somewhat. Com- 

 parison of Figs. 17 and 22 shows that the peach appears to resist injury 

 slightly better than the plum at high T and low H, while at high H and low 

 T the two are about alike. 



It should be noted that in Figs. 7, 12, 17, 22 and 23 the chart is extended 

 10° lower in humidity than the others to show the paths of the safety lines 

 in this added area. To make comparisons with the others, reading of 

 these charts should begin, not at H50, but at H60. 



