61 
gallon applied to the trees. It is a winter application, being applied 
in January and February. ’ 
Along the coast region and in northern California, where moister 
conditions prevail, this wash is very much less successful, bearing out 
somewhat the experience of the East, and doubtless explained by the 
similarity of climate in the districts mentioned with that of the Atlantic 
Seaboard. In making this wash the chief consideration seems to be 
prolonged boiling. The wash itself is practically a sulphide of lime, 
with much free lime and salt carried with it. Prolonged boiling will 
result in taking up temporarily additional sulphur, and will perhaps 
add to its caustic properties if it is applied very hot; on cooling, how- 
ever, it reverts to the simpler tri- or bi-sulphide of lime. The propor- 
tions of the ingredients and the method of combining them vary slightly 
in different sections. The following is the ordinary formula: Unslaked 
lime, 49 pounds; sulphur, 20 pounds; salt, 15 pounds; one-fourth of 
the lime is first slaked and boiled with the sulphur in 20 gallons of 
water for two or three hours; the remainder of the lime is slaked and 
together with the salt is added to the hot mixture and the whole boiled 
for half an hour or an hour longer. Water is then added to make 60 
gallons of wash. This wash is applied practically every year, or as 
often as the San José scale manifests itself in any numbers. In the 
coast region and in the northern part of the State it is necessary to 
apply it with greater ‘frequency than in the interior districts. 
HYDROCYANIC ACID GAS. 
During the past year a number of trees and plants have been 
treated with this gas at the Department, both as a means of disin- 
fecting stock to be sent out by the Division of Pomology and against 
scale insects on the Department grounds. The method of using this 
gas as at present practiced in California has been fully described 
by the writer in the last Yearbook of the Department, the details 
differing little from the old deseription, except in the fact that pure 
cyanide is used—at least 98 per cent, instead of the old brand of 58 
per cent—and the treatment is always continued about forty-five 
minutes, whatever be the size of the plant. The experiments that we 
have made here have shown that the cyanide must be used, in our 
drier and colder climate, at one-third greater strength than used in 
California, and for winter work on leafless trees double strength can be 
used without danger to the plant, and will give much greater assurance 
of effectiveness against the insect. We have employed this gas against 
the euonymus scale and against the Diaspis lanatus on large peach 
trees, in addition to the treatment of young orange and lemon trees for 
the white fly, which were to be sent out to various parts of the country, 
and the disinfection of miscellaneous stock. All of this has been very 
successful, and has demonstrated the superior effectiveness of the gas 
as an agent of thorough work, ‘The comparative results with gas and 
