142 REFOET 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
weather. Two pounds of adhesive material to each 25 pounds of poison 
and diluents may be given as an average proportion. 
The principles that should be followed in the dry application are, to 
mix the poison thoroughly with the diluents, and to apply the mixture 
as evenly and slightly as possible on the plants when the worms are 
still very young. The best time of the day to apply the poison is early 
in the morniug when the plants are still wet with dew. Dry and windy 
weather is unfavorable to an even and economical application. 
Wet application. — This is a much simpler process than the dry 
application. The required amount of poison is stirred up in a certain 
amount of water, the liquid being then evenly and economically dis- 
tributed upon the leaves of the plants. The large series of machines 
invented for this purpose accomplish this in a more or less perfect way, 
the water being broken up into a very fine spray. Most of the arseni- 
cal poisons not being soluble in water must be kept suspended by stir- 
ring, but this difficulty is easily overcome either by the employment of 
an additional hand to keep the water stirred up or by adding to the 
various pumps with which the poison is distributed a simple self-acting 
lever inside of the barrel or other vessel containing it. This, together 
with the motion of the pump, is sufficient to prevent settlement. It 
pays to add two or three pounds of flour or starch to each barrel of the 
poison mixture, not only because of the greater adhesiveness which they 
give to the poison (a very desirable object, especially in wet weather), 
but because, by their color, they help to indicate the quantity that 
has been distributed, and, also, because they serve to keep the poisons 
suspended in the water. In using flour it will be found advisable to 
mix it first in a bucketful of water and allow it to remain until it sours, 
the object being to prevent it from forming lumps. Another ingredient 
that may be advantageously added is very finely sifted wood asbea in 
such quantity as not to interfere with the distribution of the poison. 
They tend to lessen the caustic action of the poison on the plant. The 
most important point in wet applications is to have a good supply of 
water handy and readily accessible near the field, and it should be as 
free as possible from impurities. 
The best time for applying wet poisons is in the afternoon, or at 
least after the dew has disappeared. Dry weather is the most favora- 
ble, while in rainy weather the wet application, especially from above, 
should not be attempted. 
The relative advantages and disadvantages of the two methods of 
applying arsenical poisons may be briefly summed up as follows: The 
wet application is by far the cheaper so long as we are obliged to use 
a large amount of costly diluents in the dry application. It is also the 
quickest method, as a liquid spray can be thrown over more rows of 
cotton than a dry powder. During dry weather the wet application 
is preferable, while in rainy weather the dry application may be found 
more advantageous or even necessary, not only because its effect is less 
