1909.] 



PUBLIC DOCUMENT — No. 31. 



63 



Table I. — Showing the Effects of Chemicals upon Vegetation. 



A glance at the results given will show that all these sub- 

 stances, when applied at the stated strength, caused injury to 

 vegetation, but the extent of the injury and the permanency of 

 the eifect differ. Plot No. 7, treated with 1 part of white ar- 

 senic to 20 parts of water, to which was added twice as much 

 sal soda as arsenic, making arsenite of soda, gave by far the 

 best results. An examination of this plot, made the following 

 spring, showed not the slightest trace of living vegetation. This 

 treatment proved so effectual that there was no living vegeta- 

 tion for nearly two years afterwards, while on all other plots, 

 except Nos. 5 and 8, no effects were perceptible two months 

 after the treatment was made. In some instances the effects 



1 Mixed with water and applied. 



2 Twice the amount of sal soda was added to dissolve the white arsenic, 

 s At the rate of 20 pounds to 1 square rod. 



