66 FUMIGATION INVESTIGATIONS IN CALIFORNIA. 
while the dosages for larger trees were decreased proportionately 
below 1 ounce. This allowance for leakage so modified the schedule 
thai tree- 2 4 by 16 feet received as high as 1 \ ounce- per 100 cubic 
feet, while trees 60 by 44 feet received only about three-fourths of an 
ounce to the same space. The results of the use of such a schedule 
in practical fumigation should be thai the smaller and the larger 
trees receive a dosage of uniform killing power against the scale. 
After computing the dosages for tree- of such sizes as would include 
all that could be covered with a tent 60 feet in diameter, a chart 
was prepared (fig. 2s) and the dosages incorporated therein. 
How to use tin chart. — The top line of number-, commencing at 16 
and continuing through Is. 20, 22, etc.. up t<> 7s. represents the dis- 
tance, in feet, around the bottom of the tent. The outer vertical 
columns of larger numbers, on either side, commencing at 10 and 
increasing regularly to 59, represent the distance, in feet, over the 
top of the tent. The dosage of a tree of known dimensions i- found 
in that square where the vertical column headed by the distance 
around the tree intersects the horizontal line of figure- corresponding 
to the distance over. For instance, we have a tree 40 feet around 
by 28 feet over. Looking in the top line of numbers we find 40 next 
after the third heavy vertical line. The dosages computed for trees 
40 feet around are to be found in the vertical column headed by this 
number, which commences with 6 and ends with 16. Then we glance 
down the vertical column of large figures at either margin until we 
come to 2S. All dosages computed for trees 2S feet over are found 
in this horizontal line of figures, which commences with 8$ and ends 
at 16. The dosage for a tree 40 by 28 feet is found at the intersec- 
tion of this line with the vertical column headed with 40. that number 
being 11 J, the required dosage of cyanid hi ounces. Before the num- 
bers 20, 30, 40, 45, 50, and oo, in the lines at the right and left mar- 
gins are to be found blank spaces, and in the horizontal line- corre- 
sponding to these the numbers at the top of the chart are repeated 
in that part of the chart containing dosage figures. These numbers, 
repeated in this manner, make it easier for the eye to locate wit li 
certainty the dosage figures sought. In the chart used by the 
writer, the figures representing distances around and over are printed 
hi red. The lines bounding these columns of figures are also red. 
All the rest of the lines and figures are black. 
This schedule has been called "dosage schedule No. 1." by reason 
of the fact that 1 ounce to 100 cubic feet of inclosed space was taken 
•a- a ba>i> in preparing it. though, as a matter of fact, only a -mall 
number of the trees in an orchard receive exactly 1 ounce to 100 
cubic feet. 
It is not maintained that this table i- accurate to the minutest 
part of an ounce for every dosage, but the writer believes that such 
