ECONOMIC USE OF HYDROCYANIC ACID GAS 7. 
August of that year the San José scale (Aspidiotus per- 
niciosus Comstock) was found at Charlottesville, Va., 
on the grounds of Dr. C. H. Hedges. ‘This was the 
first discovery of this pest east of the Rocky Moun- 
tains, and naturally caused a good deal of apprehen- 
sion on the part of fruit growers all over the country. 
Again Mr. Coquillett was detailed by the United States 
Department of Agriculture to conduct experiments 
with hydrocyanic acid gas on these infested trees. The 
work was begun and completed in March, 1894. 
The gas process was not, however, generally 
recommended for the fumigation of deciduous trees. 
From the experiences of growers in California I felt 
certain that the gas could be applied equally as suc- 
cessful to deciduous fruit trees in the East and else- 
where, if properly handled. With practically nothing 
as a guide, except the general work done in California, 
and little or no encouragement from leading Eastern 
entomologists, I began a series of experiments, in the 
spring of 1897, upon young plum, pear, apple, and 
nectarine trees. The results of these preliminary ex- 
periments were so very satisfactory that I was prompted 
to continue my work on bearing trees in the fall of 
1897: With the aid of Robert S. Emory, of Chester- 
town, Md., a successful fruit grower, we perfected an 
outfit and completed the first successful fumigation of 
a large orchard in the East. The results of this work 
were watched with much interest in this and other 
countries. While the methods of generating the gas 
have not been materially changed, the amounts of 
chemicals have been adapted to suit conditions. ‘The 
apparatus for containing the gas has been improved, 
