762 NEW YORK STATE MUSEUM 
better condition than it was two years ago. It is only necessary 
to compare pl. 5, 6 to obtain a relative idea of the value of 
spraying for San José scale. The experimental orchard was 
the first in that vicinity to become infested with the San José 
scale; and two years ago it was composed of a very bad-looking 
lot of young trees. Today the conditions are reversed, so far 
as these two orchards are concerned, and the later infested, 
near by orchard is in much worse shape than the other. It is. 
true, that the former is composed of appletrees set a consider- 
able distance apart, and that naturally makes the orchard look 
thin compared with the more closely set peachtrees and pear- 
trees, but a close examination shows that the true relative con- 
dition of the trees is very fairly expressed in the two plates. : 
The poor results obtained from early spring applications of 
kerosene and mechanical emulsions of the same in 1900, led 
to the concentrating of the work on the more promising insecti- 
cides, namely, crude petroleum and whale oil soap in various 
combinations. Two crude petroleums were used, care being 
taken to make field tests of the oil just before spraying, conse- 
quently there can be no doubt regarding its weight as deter- 
mined by the hydrometer. One of the crude petroleums used 
was obtained from a local oil dealer handling the products of 
the Standard oil co. This is a quite fluid, greenish oil, and it 
gave a field reading of 41.8° Beaumé. It was presumably about 
the same as that used last year, as it appeared no different and 
was obtained from the same source. The other crude petroleum 
was received directly from the Frank oil co., Titusville Pa. 
This was of a light amber color, and it was said to test from 
44° to 45° on the Beaumé oil scale. In the field it gave a read- 
ing of 43.3° Beaumé. Both of these tests were made at a tem- 
perature of about 65° F. These two crude petroleums, for the 
sake of brevity, have been characterized in our records as 
Standard oil and Titusville oil respectively, and these names 
will be used in the following pages. Comparative tests of 
mechanical emulsions of both these oils were made, and the 
results are given below. The spraying was done April 11, which 
was bright, with at times a rather strong wind. 
