New York AGRICULTURAL EXPERIMENT STATION. 225 
ANALYSIS OF PARIS GREEN AND OTHER INSECTI- 
€IDES:* 
During recent years paris green has come to be used to such an 
extent by farmers and offered such an inviting field for adulteration, 
that in 1898 a law was passed to prevent fraud in the sale of paris 
green in New York State. This law was defective because it failed 
to define paris green properly and did not prevent the addition of 
white arsenic (arsenious oxide). The presence of white arsenic in 
paris green may render it unfit for spraying purposes, because 
white arsenic is sufficiently soluble in water to burn foliage, if 
present in amounts exceeding 3'% per ct. These defects were cor- 
rected in 1901. As amended, the law was essentially as follows: 
1. It provided that every manufacturer should guarantee the per- 
centage of arsenious oxide in paris green or any analogous product. 
2. Paris green must contain arsenic in combination with copper, 
equivalent to not less than 50 per ct. arsenious oxide. 
3. Paris green must not contain arsenic in water-soluble forms 
equivalent to more than 3% per ct. arsenious oxide. 
Paris green contains as its chief constituent a compound called 
copper aceto-arsenite, which, when chemically pure, contains 
PNESEMI@USUOMIGC . 2240 Cec ces guts ee sos 58.64 per ct. 
Money Odes tt fer ons eke ete Bie Ona 
PNCCHIOTACICs no. 4s) Pract ahr aats = ye LOLOOy rapes 
It may be regarded as approximately consisting of 
Oppel USCMES ar. ps econo ie sa we eee 82 pervck. 
GopmegraCetate. ise sie acs Sen cs ww oles 6 18 
During the four years, 1899 to 1902, 130 samples of paris green 
were examined. The amount of arsenious oxide varied from 55.34 
to 62.87 per ct., averaging 57.24 per ct. 
The amount of copper oxide varied from 26.53 to 31.2 per ct. 
and averaged 29.82 per ct. 
The amount of arsenious oxide in combination with copper varied 
from 49.70 to 58.45 per ct. and averaged 55.87 per ct. 
The amount of water-soluble arsenic varied from 0.61 to 2.2: 
per ct. and averaged 1.30 per ct. 
The results showed that the paris green in the market at the 
time the samples were taken were of good commercial quality. It 
* Bulletins 165, 190, 204, 222. 
8 
