METUOD «'l CT.N KHATINi; THE CAS. 35 
indicating the dose, the circumference in yards (paces), and the difference (thai is, 
the amount the dose must be varied) should the distance around be more or less 
than the amount indicated for an average tent. 
This suggestioD in regard to the marking of bents with the dosage 
to obviate the use of printed tables seems to the writer to be of con- 
siderable value under some circumstances. One objection to the use 
of differentials in this manner is that the cubic capacity and dosage 
does not increase in direct proportion to the increase in circumfer- 
ence with a given distance 4 over the top. To illustrate the method 
of marking the tents with the dosage, when desired, a tent meas- 
uring 30 feet over from ground to ground will serve as an example. 
The tabic 4 in the appendix shows that for every 5 feet of difference 
in the measurement of the circumference of a tent measuring 30 feet 
over the top. the amount of cyanid is increased or decreased one- 
half ounce, or 0.1 ounce for each foot. With the figure 30 on the tent, 
we would place the dosage of a tented tree measuring 30 feet in cir- 
cumference. The dosage called for by the table for a tent of this 
size (30 by 30) is 9\ ounces. Following this the differential, or 0.1 
ounce, is placed. The entire directions for obtaining the dosage 4 
would read 30 — 94 — 0.1. A tented tree measuring 30 feet over and 
38 feet in circumference would require 9-i ounces plus 0.8 ounce or, 
for practical purposes, 10J ounces. If the measurement was 30 feet 
over and 25 feet in circumference, the dosage would be 94 less 0.5 
ounce, or 9 ounces. 
When tables are worked out in detail, as they should be where 
accurate 1 work is desired, reference to them is undoubtedly by far 
the quickest and safest method under ordinary circumstances. 
METHOD OF GENERATING THE GAS. 
In order to permit of making the measurements of tents and esti- 
mating the dosage with the care hereafter recommended and with 
the least possible delay, it is sometimes advisable, in operations on 
a large scale, that the cyanid be weighed during the day or at other 
times when it is not advisable to fumigate, or, if done at night, that 
an additional helper be employed. Such a helper, in addition to 
weighing the cvanid, might look after the replenishing of the stock 
of cvanid and acid at the cart as needed and assist in measuring the 
tents and emptying the generating jars. The cyanid should be 
weighed up in lots of \, 1, 2, 5, 10, and 20 ounces, put into paper 
bags of convenient size, and protected from dampness. When the 
tented trees all measure less than 34 feet over the to]) from ground 
to ground, the doses of 20 ounces each will not be required, and 
when measuring more than this the lots of one-half ounce may be 
dispensed with. At the cart, drag, or tray these bags of cyanid 
should be kept in separate boxes, or in separate compartments of a 
