24 
FUMIGATION INVESTIGATIONS IX CALIFORNIA. 
vary considerably in their estimates, many trees in the above-men- 
tioned orchards must have received a much greater dosage than was 
necessary for scale eradication, thus resulting in a waste of cyanid 
and acid. 
In Table I have been arranged the dosage estimates which were 
scheduled in different orchards by three different rumigators. After 
the trees had been covered with tents the exact contents were com- 
puted by the writer from actual measurements. The dosages given 
in these tables are not for scattered individual trees selected because 
of their irregularity in size, but each table embraces a continuous 
number in a single row taken at random, regardless of the size or 
regularity of the trees. As great a lack of uniformity as that shown 
in each table might be looked for throughout the orchard. These 
schedules of dosage were used against the red and purple scales, 
species considered by most fumigators to be about equally resistant 
to the gas. The reader will note the wide difference in the dosage in 
the estimates of the different fumigators. 
Table I. — Variation in the dosages estimated for several consecutii t tret s by thret different 
fumigators. 
Work of first fumigator. 
Work of second f amigator. 
Work of third fumigator. 
Dosage 
recom- 
mended. 
Actual 
volume 
of 
treated 
tree. 
Ounces. 
11 
12 
10 
10 
10 
12 
12 
12 
12 
Cubic feet. 
1,090 
2,050 
1,369 
1,603 
1,516 
1,440 
1,663 
1 . 755 
1,350 
1,175 
Volume 
of space 
in tent 
to each 
ounce of 
dosage. 
Cubicfeet. 
150 
170 
135 
165 
150 
120 
140 
145 
110 
130 
Dosage 
recom- 
mended. 
Actual 
volume 
of 
treated 
tree. 
Volume 
of space 
in tent 
to each 
ounce of 
dosage. 
Dosage 
recom- 
mended. 
Ounces. 
Cubicfeet. 
11 
1,000 
7 
400 
15 
1,800 
10 
600 
16 
2,200 
15 
1,800 
16 
2,400 
1 
2,000 
IS 
2,200 
17 
2,200 
12 
1,250 
16 
2,500 
Cubicfeet. 
90 
CO 
120 
60 
140 
120 
150 
125 
120 
130 
105 
156 
Actual 
volume 
of 
treated 
tree. 
Volume 
of space 
in tent 
to each 
ounce of 
dosage. 
Ounces. 
6 
4 
4 
5 
4 
4 
Cubic feet 
1.500 
1.100 
803 
1,200 
1.100 
900 
1,300 
1,150 
950 
950 
900 
1.550 
Cubicfeet. 
250 
275 
200 
240 
260 
230 
190 
258 
THE INITIAL PROBLEM CONFRONTING THIS INVESTIGATION 
After becoming acquainted with the existing methods of fumiga- 
tion, it was realized that one of the first problems to be solved was 
to devise some accurate system of determining dosage which would 
obviate the errors due to guesswork. It at once became apparent 
that the only way in which this result could be attained was by 
determining accurately the cubic contents of the space inclosed by 
the tent and giving the tree a dose proportionate to the content-. 
It was also apparent that before such a system could be put into 
operation, after having been worked out in practice, it would be 
