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 

 that trees 24 by 16 feet received as high as IJ ounces 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 that the smaller and the larger 

 trees receive a dosage of uniform killing power against the scale. 



After computing the dosages for trees of such sizes as would include 

 all that could be covered with a tent 60 feet in diameter, a chart 

 was prepared (fig. 28) and the dosages incorporated therein. 



How to use the cliart. — The top line of numbers, commencing at 16 

 and continuing through 18, 20, 22, etc., up to 78, 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 is found 

 in that square where the vertical column headed by the distance 

 around the tree intersects the horizontal Ime of figures corresponding 

 to the distance over. For instance, we have a tree 40 feet around 

 by 28 feet over. Looking m the top line of numbers we find 40 next 

 after the third heav}^ 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 margm until we 

 come to 28. 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 mtersec- 

 tion of this Ime with the vertical column headed with 40, that number 

 being llj, the required dosage of cyanid in ounces. Before the num- 

 bers 20, 30, 40, 45, 50, and 55, in the lines at the right and left mar- 

 gins are to be found blank spaces, and in the horizontal lines 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 with 

 certainty the dosage figures sought. In the chart used by the 

 writer, the figures representing distances around and over are printed 

 in red. The Imes 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 mclosed space was taken 

 as a basis in preparing it, though, as a matter of fact, only a small 

 number of the trees m an orchard receive exactly 1 ounce to 100 

 cubic feet. 



It is not maintained that this table is accurate to the minutest 

 part of an ounce for ever}^ dosage, but the writer believes that such 



