FUMIGATION OF CITRUS TREES. 35 
determined they were introduced into a chart of the same general 
form as that used by Dr. Morrill. Such a chart form has been known 
in scientific work for many years and was first introduced into fumi- 
gation scheduling by Prof. Woodworth. 1 
An average-sized orange tree, one 41 feet in circumference by 28 
feet over, was taken as a basis in the preparation of the schedule. 
The cubic contents of the tree was determined and a dosage calcu- 
lated which would give it 1 ounce to each 100 cubic feet. Trees of 
other dimensions, both larger and smaller, were then considered and 
their contents determined. In working out the dosage for these other 
trees not only was the cubic contents taken into consideration but 
also the rate of leakage as compared with that of the tree 41 by 28 
feet in size. Trees which were smaller than this would have a greater 
proportional leakage rate while the larger ones would have less, as ex- 
plained on pages 33-34. In securing the dosage for various trees, those 
smaller than 41 by 28 were given sufficient cyanid in excess of 1 ounce 
per 100 cubic feet to offset the increased leakage, while the dosages for 
larger trees were proportionately decreased below the 1 -ounce rate. 
This allowance for leakage so modified the schedule that some of the 
smaller trees were receiving in excess of \\ ounces per 100 cubic feet, 
while trees as large as 60 by 44 were receiving only about three-fourths 
of an ounce to the same space. It thus can be seen that each dosage 
was worked out independently and so correlated to the other dosages 
that when placed in schedule No. 1 the ultimate result was that of a 
schedule which should approximate uniform results throughout. 
How to use the chart. — Referring again to figure 9, the top line of 
numbers, commencing at 16 and continuing up to 68, represents the 
distance, in feet, around the bottom of the tent. The outer vertical 
columns of numbers, on either side, commencing at 10 and increasing 
regularly to 49, represent the distance, in feet, over the top of the tent: 
The dosage of a tree of known dimensions is found in that square where 
the vertical column headed by the distance around the tree intersects 
the horizontal line of figures corresponding to the distance over. For 
instance, in the case of a tree 40 feet around by 28 feet over, in the top 
line of numbers 40 is next after the third heavy vertical line. The 
dosages computed for trees 40 feet around are to be found in the ver- 
tical column headed by this number, which commences with 7 and 
ends with 16. Then the vertical column of large figures at either 
margin is followed down until 28 is reached. All dosages computed 
for trees 28 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 intersection of this line with the vertical col- 
umn headed with 40, that number being 11, the required dosage of 
cyanid in ounces. Before the numbers 20, 30, 40, and 45 in the lines 
i Bui. 152, Univ. of Cal. Agr. Exp. Sta., p. 6, 1903. 
