3898 Report or INSPECTION WoRK OF THE 
DISCUSSION OF RESULTS OF CHEMICAL ANALYSIS. 
1. Total arsenious ovide—In the 40 samples of materials sold 
as Paris green, examined by us, the amount or arsenic equiva- 
lent to arsenious oxide, varies from 56.13 to 62.87 per ct., and 
averaged 58.10 per ct. This average is over one per ct. higher 
than that found last year, and is about one-half per ct. below 
the equivalent of arsenious oxide contained in pure copper aceto- 
arsenite. So far as the total arsenic content is concerned, the 
amount found indicates a high quality of Paris green. The 
variation is about the same as last year and, excepting four 
samples, is within surprisingly narrow limits. Where the total 
amount of arsenic present in Paris green the only point to be 
considered, the quality would be regarded as very satisfactory, 
but we must consider at the same time the amount of water- 
soluble compounds of arsenic present in Paris green. 
2. Water-soluble compounds of arsenic.—The presence of water- 
soluble arsenic in Paris green is seriously objectionable owing 
to the fact that soluble arsenic compounds injure foliage. 
Hilgard, of California, states that in the dry climate of Cali- 
fornia, Paris green injures foliage when it contains an equiva- 
lent of more than four per ct. of arsenious oxide in the form 
of soluble arsenic compounds. The water-soluble arsenic most 
commonly occurring in Paris green is in the form of arsenious 
oxide, commercally known as common white arsenic. 
The method of analysis used by us in determining the amount 
of water-soluble arsenic compounds in Paris green should show 
the full amount of such compounds that would be found in 
actual field work where Paris green is mixed with water at the 
rate of one part by weight of Paris green to 1000 parts of water 
and the mixture used soon after preparation. By longer extrac- 
tion with water, larger quantities of soluble arsenic compounds 
can be obtained; but for our purpose, it is desirable to approxi- 
mate the amount likely to be found in actual field practice 
in the use of Paris green under the conditions commonly em- 
ployed. It would, in our judgment, be proper to condemn for 
