RECENT WORK WITH HYDROCYANIC ACID GAS 203 
from without. The foliage of the plants should be 
dry. A temperature not exceeding 60° F. and prefer- 
ably of 50° F. is desirable. Above 60° F. there is 
risk of injury to the foliage. 
For mealy bug, 3 ounces cyanide, 5 ounces acid, 
I5 ounces water per 1,000 cubic feet, either before the 
vines bloom, or when grapes are coloring, or after the 
crop has been gathered. At either of these stages no 
harm results to either foliage or fruit. Avoid fumi- 
gation when the vines are in bloom, or before the 
grapes have commenced to ripen. 
for ordinary greenhouse pests, such as aphis, 
dolphin, whitefly, slugs, woodlice, red-spider, and 
caterpillars, a dose not exceeding 134 to 2 ounces cya- 
nide, 4 ounces acid, 7 ounces water per 1,000 cubic 
feet, has been found satisfactory in England. For a 
detailed account of greenhouse fumigation see Chap- 
sap. @ AVE 
Use in New South Wales.—In the center of the 
citrus-growing belt of New South Wales, W. J. Allen, 
an expert of the government, has conducted some very 
satisfactory experiments with hydrocyanic acid gas in 
cooperation with the Glenorie Progress Association. 
Various sprays were tried at the same time and com- 
pared with the gas treatment. In his report of the 
practical tests, printed in Vol. XII. of the Agz- 
cultural Gazette of New South Wales (see also Ag7?- 
cultural Gazette for August, 1899, and July, 1900), Mr. 
Allen says: 
The fumigation of the trees with hydrocyanic acid 
gas gave the best results of all. This was conceded 
