DOSAGE TABLE. 



67 



sides of the tent. If the only available tents are of inferior quality and 

 fall short of being as nearly gas-tight as the best of material, increases 

 in dosage may be advisable. When it is desired to fumigate with a 

 thoroughness approaching extermination, an increase may be made 

 of from 10 to 25 per cent. Such a course is frequently advisable to 

 check the further spread of the fly in newly infested localities or in 

 newly infested groves. In the fumigation of very small trees, 20 feet 

 over or less, there seem to be certain factors sometimes interfering 

 with efficiency which have not so far been thoroughly investigated. 

 It is possible that in the using of crocks of 2 or 3 gallons capacity for 

 doses less than 5 ounces the mixture of acid and water fails to gen- 

 erate sufficient heat to cause quick chemical action, the heat absorbed 

 by the jar being the disturbing factor. This may be partly obviated 

 by using powder or very small lumps of potassium cyanid when the 

 dose is 5 ounces or less, but it seems advisable also to increase the 

 amount by one-half or three-fourths above the recommended dose. 

 If the size of the crock and consequent undue loss of heat is the prin- 

 cipal disturbing factor, future experience may show that it is desirable 

 to have on hand for use in fumigating very small trees a supply of 

 half-gallon crocks or 1 -quart stone chinaware pitchers. 



In the table the amount in each case represents the next half ounce 

 above the dosage which the detailed estimate calls for, whenever this 

 dosage was more than one-tenth ounce above the even ounce or half 

 ounce. For example, when the detailed calculation calls for 19.2 

 ounces the number in the working table is 19^ ounces, and when for 

 19.7 ounces the number is 20 ounces. In using the table in the field, 

 when the reading on the graduated tent shows the approximate dis- 

 tance over the top to be an odd number of feet, the next even num- 

 ber above should be selected. In the same way, when the exact cir- 

 cumference is not shown at the top of the table, the next highest 

 number should be selected. 



To illustrate the method of using the table of dosage, the following 

 examples show the measurements and dosage called for in the case 

 of five trees of various sizes : 



Measurements of, and dosage for each of five trees of various sizes. 



At all times it should be borne in mind that it is advisable to use 

 one-half or even 1 ounce more than called for by the table rather than 

 the smaller amount. 



