EXPERIMENTS WITH KEROSENE EMULSIONS. 
161 
parts kerosene, with vigorous agitation. When the kerosene disappears, add three 
parts water, and agitate till a homogeneous emulsion is formed. 
This is more pleasant to use than soapy solutions, and costs- 
Cents per gallon. 
Standard solution, 50 per cent, kerosene 22 
Dilution A', 2 per cent, kerosene 0. 83 
Dilution B', 1.25 percent, kerosene 0.55 
Dilution C, 1 per cent, kerosene 0.44 
Dilution D', 6.25 per cent, kerosene 0.225 
Dilution E', 5 per cent, kerosene 0.22 
The A' and B' were not stable longer than two days ; the remaining dilutions barely 
one day. 
With the exception of the zamia emulsion, all others were better to use tho day of 
manufacture. 
A mixture called murvite was sent mo for trial. It gave similar results to the milk 
emulsions, when diluted in a corresponding manuer. 
Effects upon the Cotton-plant. — These varied greatly, owing to the weather subsequent 
to the application. 
fanulsions A and B, A', B', 1£ to 2 per cent, kerosene, did not harm the cotton-plant 
if two cldudy or showery days followed their use. A bright sunny day scorched the 
tips and edges of the tender leaves badly. 
Emulsions C, D, and E, C, D', E', produced no bad results upon leaves or bolls, 
and were repeatedly tried, with uniform effects. 
Effects uj)on Land. — 1. I colonized five hundred full-grown larva 1 upon five cotton- 
plants, and sprayed them with emulsion A. soap series. In five minutes forty larva? 
dropped off the plants, trembled, and soon died; in an hour but one hundred re- 
mained, none feeding, all hanging from the stems and leaves ; in three hours but eight 
survived; the next day all were dead, and the cotton-leaves badly withered. 
2. I prepared forty gallons of solution B', milk, and sprinkled thoroughly one-fourth 
acre of cot ton. The stalks average 7 feet in height, and the worms were very plentiful. 
The next day apparently but one in each hundred was living; the day following 
that the difference was quite marked, and at this time, three weeks afterward, the 
■mounding cotton is defoliated, the sprinkled section remaining vigorous and green. 
3. I colonized one hundred larva), all ages, on a cotton-plant: sprayed these with 
solution C, milk, fifteen worms fell off in twenty minutes; the remainder quit feed- 
ing. The next morning but two remained, feebly alive. 
4. One hundred large larva) were colonized and sprayed with solution D', milk. In 
ten minutes ten dropped off; in half an hour but thirty-five showed vitality ; in four 
hours all were dead. 
5. One hundred larva), small size, were sprayed with tho one per cent, kerosene- 
zamia emulsi on ; all died within an hour. 
6. One; hundred Hinall larva) sprayed with emulsion B, soap, died in one hour. 
7. Three hundred large larva) were sprayed with solution C", milk. The next day 
but twelve showed signs of life, and they were evidently moribund. 
8. Three hundred large larva) were sprayed with the zamia emulsion; all died 
within four hours, and the repetition of experiment 3 with this solution gave better 
results than with milk or soap emulsions, the zamia perhaps contributing some toxic 
action. 
I repeated these experiments with all the emulsions till satisfied that an emulsion 
of one per cent, kerosene, thoroughly applied, was fatal to all larva) it reached, and 
harmless to the cotton-plant. 
I noted that as soon as sprinkled the small larva) stopped eating, straightened, and 
quickly fell to the ground. Older larva) would tremble, evacuate fasces, and hang 
suspended some time. The anal extremity lived longest. 
The addition of one pound sulphide of potassium to forty gallons of any emulsion 
seemed to increase the rapidity of its toxic action, but it is objectionable as to smell 
and its destructive action upon rubber hose. 
G3 CONG 11 
