4 FUMIGATION METHODS 
Speaking of the early experiences with this gas, 
Prof. C. W. Woodworth says that previous to the 
time of the publication of Morse’s soda method, Mr. 
Coquillett accomplished a similar diminution of injury 
by slow generation of the gas. This Mr. Coquillett 
accomplished by means of a generator consisting of two 
parts: from one the sulphuric acid passed in a fine 
stream, regulated by a stop-cock, into the other con- 
taining dry cyanide. ‘These facts were clearly set forth 
by Alexander Craw in a paper before a meeting of 
fruit growers at Los Angeles, in October, 1887. 
The ‘‘ dry gas process’’ was soon devised by Mr. 
Coquillett. It consisted in passing the gas from the 
generator through sulphuric acid, allowing it to come 
in contact with the foliage. Inthis he used a solution 
of cyanide. ‘This was the situation at the time of the 
publication of Mr. Coquillett’s first paper, cited above, 
wherein these three processes were described quite 
fully. He strongly recommended his last process as 
the cheapest and most convenient; and Mr. Morse, in 
a later paper, practically abandoned his soda method in 
favor of the dry gas process. 
Injury to trees from the first has been a specula- 
tion and controversy, and even now it must be con- 
fessed that we are far from possessing sufficient data to 
enable us to solve any considerable part of the problem. 
The results have been very uncertain, proving that 
there are a number of factors involved. One of the 
earliest explanations suggested was that faulty dis- 
tribution of the gas would tend to cause buraing 
wherever the pure or slightly diluted gas came in: ;on- 
tact with the leaves. Practical experience bore out 
