New York AGRICULTURAL EXPERIMENT STATION. 203 
tion of of the paris green used in this experiment. It was pur- 
chased of a Geneva merchant for 16 cents per pound. Analyses 
made by Mr. W. H. Andrews gave the following results: 
Bema CCN TOUS SOX LOE: © i. sidn, cai sh eons nig hell wild» whe late 59.85 per ct. 
MIRC OTC T LOX LOG 035 caida aguletetnne ote acta at ores ew are 27.63 per ct. 
Soluble arsenic oxide obtained by treating one gram with one 
liter of water: 
Treated 24 hours. 
AME VME RS ke bhai pce rests on abe siahy cals! oo Mew tai) ie eee» 1.83. per ct. 
=) PEEL EE leg ohn knelt Pr, COO PSS aE TPO sah 2.08 per et. 
aes We Se et dy ets pris ois a choapeycttsieds Foteyels L216 persce 
| Treated 10 days 
RRNA ORL ile te i ccetc Gk 3 Soha hgaR a ous at w sinners © Seta gsm a Gees 6.81 per ct. 
BR SILLY GIS. ies 6 we.e 0 00's wget Na Pete ea ee abe el: 6.81 per ct. 
RESULTS. 
Effect on the foliage.—Throughout the entire experiment there 
were no indications that the paris green caused any injury to 
the foliage whatever. While looking for such injury on July 9, 
it was observed that occasionally a leaf was affected with a trou- 
ble diagnosed as sunscald. On the tips and margins of some 
of the leaflets of the younger leaves there were dead, copper- 
colored areas one-half inch to one inch across. They were not 
sufficiently numerous to attract the attention of a casual obser- 
ver. It is believed that they were caused by the action of the 
sun (on July 8) on tender, rapidly growing foliage. Certainly, 
the paris green had nothing to do with them, for they were 
quite as numerous on the check rows as on the rows treated with 
paris green. 
The only other dead spots on the leaves were those caused by 
late blight, Phytophthora infestans, and these could be easily 
and positively identified by the presence of the fungus. There 
were no spots of early blight or anything resembling 1t. 
Effect on late blight.—An unexpected result of the experiment 
was the discovery that paris green is of considerable value as a 
preventive of late blight, Phytophthora infestans. Traces of 
this disease were first seen’ on the check rows (Series I) July 
23. By August 2 the rows of Series I, II and I1I were plainly 
