ESTIMATING GAS FOR ORCHARD WORK af 
cated, it is dificult to measure and determine accurately 
the cubic content of a tented tree. To simplify the 
measurement and estimation of the tent the following 
table has been prepared by Prof. Woodworth, of Cali- 
fornia. ‘The center column gives the various doses 
corresponding to the size of the trees in the columns 
on either side. Thus, on one side it has been calcu- 
lated so as to give three parts of hydrocyanic acid gas 
in 1000 parts of air; on the other side, two parts in 
1ooo of air. For winter treatment for deciduous trees 
the first or 0.3 per cent. gas is suggested. This is 
about equivalent to the general recommendations given 
for the Eastern States. One-half of this amount is not 
far from the commonest practice in California for 
citrus trees. ‘The 0.2 per cent. formula is suggested 
for citrus trees. It agrees with the amounts used by 
some of the most successful fumigators in California. 
Other individuals get fair results with scarcely more 
than half this amount. 
The measurements to be taken when using this 
table are (1) around the tent, and (2) from the 
tent from ground to ground. If these two measure” 
ments are about equal, as will be found on many 
orange trees, the number nearest the measure- 
ment is found in the circumference column, and 
the corresponding dose will be seen in the center 
column. If these two measurements are not nearly 
the same, the outside columns become useful, for 
they show for each size how much difference must 
occur to make necessary a half ounce increased or de- 
creased in dose ; that is, for each differential there must 
be added or deducted one-half ounce of cyanide. For 
