162 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
The sulphides will bear further study. 
Still, with all these emulsions, their cheapness and safety, I have a grave doubt as 
to the applicability of any to long-staple cotton. 
I tried a number of experiments to determine the minimum quantity needed to 
thoroughly spray an acre of cotton during August or September. In one very care- 
fully conducted experiment I found most of the plants averaged 6 feet high, in rows 
of 4 feet apart, and 2 feet between the plants in the drill. 
In this case 160 gallons barely sufficed for one-half an acre, and as it could not be 
applied from a cart it was hand-carried. Two field hands required four hours to com- 
plete the experiment. 
The labor of preparing solutions, and for carrying and using a fountain pump, w ill 
prevent small farmers, especially colored people, from trying these remedies. 
The cost of this experiment was, 160 gallons solution C, 70. cents; labor, 60 cents, 
or s-2.60per acre, and with the close margin between profit and expense in cotton- 
growing, this slight cost will deter many. 49 
We hardly need to add that Dr. NeaFs method of application has 
been very crude and wasteful. Instead of barely reaching over one- 
half acre the 160 gallons of diluted emulsion ought to suffice for at least 
five acres, and his estimates of cost are of course much exaggerated. 
OIL OF CREOSOTE. 
This cheap material has lately been recommended to us as an insect- 
icide, but we have had no opportunity so far to try it on the Cotton Worm. 
However, the experience we had with it last fall as a remedy for Cabbage 
Worms (Pieris and Koctuid larvre) is by no means encouraging, one 
tablespoonful of the oil stirred up (after Saunders' method) in one gal- 
lon of water not being sufficient to kill the larger worms, while at the 
same time the spray ruined young turnip-plants. 
OIL OF TAR. 
This does not appear to differ essentially from the former, its effect 
on the plant beiug likewise more violent than that of kerosene. Mr. 
Schwarz reports the following experiment with this material: 
No oil of tar could be obtained at Selma, but only a small bottle in which some of the 
oil had been, a few drops still adhering to the glass. The bottle was filled with water, 
the contents shaken up, and then applied to plants and worms by means of the parlor 
atomizer. I estimate the proportion of the oil to the water to be less than 1 to 300. 
This mixture proved deadly to every worm, but also scorched the leaves much more 
than kerosene. Owing to the very small quantity of the oil at hand I could not 
make any further experiments with still weaker solutions. 
Since these two oils are not cheaper than kerosene and are inferior 
as insecticides, they are not likely to come into general use. 
GAS-TAR WATER. 
If water is left standing for several days over common gas-tar it be- 
comes strongly impregnated with the smell of the tar, and the idea 
occurred to us to utilize such water against the Cotton Worm. Experi- 
