PARIS GREEN ITS USE AS A POWDER. 145 



large series of trials with poisons iu powder form conviuced nie that 

 this waste cannot be nuiterially lessened by a careful handling of the 

 sieve, or by employing several more layers of muslin in addition to the 

 one or two now generally used. Application by means of the bellows 

 is too irregular, while application with the hand is, with some practice, 

 considerably less wasteful. 



"The most economical distribution of the mixture I could devise, for 

 experiments on a small scale, was by means of a stiff brush. A com- 

 mon shoe-brush is dipped in a flat vessel containing the mixture.''^ The 

 greatest portion of the adhering poison is then shaken off by knocking 

 with a stick on the handle of the brush. The still adhering poison is 

 then thrown on the plants by drawing a stick across the brush. The 

 poison can thus be aj^plied from any direction, and the amount be reg- 

 ulated at will. Three average-sized plants were accordingly dusted on 

 September 2 ; the first very slightly from above, the two others from 

 below. In applying from below, the poison finally covers both the un- 

 derside as well as the upper side of the leaves. I am quite unable, 

 however, to calculate the amount of poison mixture I used, but it is cer- 

 tain that each plant did not receive the tenth part of the amount it 

 would have received in the apjdications with the sieve. The plants 

 w^ere dusted early in the morning, the poison adhering very well also to 

 the underside of the leaves. There were numerous worms on all jdants 

 at this time, while others were continually hatching. A moderate rain 

 shower about six hours after application washed off' most of the poison 

 applied from above, while it had but little iulluence on that applied 

 from below. However, w^herever tht^re were holes in the leaves, the 

 poison on the underside was converted into paste, and, in a few places, 

 washed away. 



"The application on the first plant proved to be of very little use, 

 though I found three dead worms under the plant next morning. The 

 two other plants were, however, fully ])rotected for about five days, and 

 almost entirely cleared from the worms, when the migratory worms over- 

 ran them. Against the superior number of these worms the poison 

 was of no avail, though a vast number of them were killed before the 

 plants were stripped. I have not the shghtest doubt, however, that in 

 ordinary times such slight api^lication of dry Paris green from below is 

 fully sufficient to protect the plants." 



That such application from below is not only practically possible, but 

 can be effected much more rapidly than the sieving method, will be de- 

 monstrated further on in discussing the machines invented for this pur- 

 pose. The adoption of the new machines will considerably reduce the 

 cost of the dry application of Paris green without iu the least lessening 

 its efficacy. Its cost per acre of cotton, when applied with the sieve, 

 ranges from 75 cents to $2, according to the first cost of material and 

 different modes of application, or, again, to the size of the plants at the 

 time of the api)llcation. 

 63 CONG 10 



