KEROSENE AS AN INSECTICIDE. 
155 
it as a substitute for Hour in the application of arsenical poisons and 
pyre thrum powder. On this subject Mr. Schwarz reports as follows : 
At first I selected dust from the nearest road at hand and sifted it through a very 
fine sieve covered with a quadruple layer of tine muslin. I found, however, that this 
dust was largely composed of particles of sand without any adhesive power whatever, 
and which, moreover, rendered the dust very heavy and quite unsuitable for any ex- 
periment. This sand is very line, and I failed to eliminate it by using additional layers 
of muslin. I did not succeed better with dust prepared from the dry clay so common 
along the river bank near Selma. Finally I obtained a suitable very tine dust by 
sifting the rich black earth, which of course I had previously well dried. This dust is 
comparatively light, and of considerable adhesive power even in dry weather. 
While we attach but limited value to dust either for preventing: the 
moths from ovipositing, driving oil' the worms, or killing them in the man- 
ner just mentioned, still it might prove valuable as a diluent for arsen- 
ical poisons where flour and other diluents cannot be obtained, and 
more attention ought to be paid to this cheap and easily obtainable 
substance as a remedy for various insect pests other than the Cotton 
Worm. The inseeticide property of dust mentioned in this connection 
is not peculiar to road dust alone, but is possessed by every substance 
which adheres to the worms in a sticky, paste -like covering. Thus by 
the application of flour stirred up in water many small worms may be 
killed, and the only results obtained by our agents in the application of 
diluted dough and yeast are attributable to their action in the manner 
here alluded to. 
OILS AM) ALLIED SUBSTANCES. 
KKKOSENE. 
It is a well-known fact that this is a most powerful insecticide, and ex- 
periment has shown that a fine spray of kerosene applied to the leaves 
will kill all worms thereon in a remarkably short time. This deadly 
effect is produced by contact, a very small quantity of the oil applied 
to the worm causing death. We have thus a very cheap and sure rem- 
edy, which, moreover, cannot be called poisonous to higher animals, but 
unfortunately the oil has the same pernicious effect on the plant as on 
insect life, and the problem is to apply it in such fine spray, or so much 
diluted as not to injure the plant and at the same time touch every worm. 
The finest spray, produced by a parlor atomizer, of the undiluted oil is 
Sufficient to kill the leaves, the cotton plant proving to be exceedingly 
sensitive to the effect of the oil, much more so, in fact, than many other 
plants. The use of the undiluted oil being, therefore, impracticable, 
there remains only to try to apply it in dilution. The onl\ available 
diluent hitherto known being water, a new difficulty arises, viz., to mix 
the oil with the water so as to produce a homogeneous or nearly homo- 
geneous mixture of the two. To a limited extent, and only on a small 
scale, this can be accomplished by very violently agitating the mixture. 
More useful, but also practicable only on a small scale, is the following 
method, recommended by Mr. William Saunders, of the Department of 
