42 BULLETIN NO. 1, DIVISION OF ENTOMOLOGY, 
hot water would emulsify 1 gallon kerosene, forming a gelatinous com- 
pound that was quite stable. 
Less than this percentage of soap acted badly with kerosene, and a 
greater amount did not appear to emulsify a large amount of kerosene. 
This mixture, containing 50 per cent. kerosene and costing 26 cents 
per gallon, I adopted as a standard. 
I prepared the following dilutions: 
A. One gallon standard solution to 24 gallons water, 2 per cent. kero- 
sene, cost 1.04 ¢. per gallon. 
B. One gallon standard solution to 39 gallons water, 1.25 per cent. 
kerosene, cost 0.65 ¢. per gallon. 
C. One gallon standard solution to 49 gallons water, 1 per cent. kero- 
sene, cost 0.52 ¢. per gallon. 
D. One gallon standard solution to 79 gallons water, .625 per cent. 
kerosene, cost 0.325 ¢. per gallon. 
HK. One gallon standard solution to 99 gallons water, .5 per cent. kero- 
sene, cost 0.26 c. per gallon. ; 
Emulsions A, B, and C presented a milky color, and were quite per- 
manent; D and E showed some tendency to disintegrate after four days’ 
standing. \ 
I tried solutions of many native plants, and found the zamia finely 
adapted for an emulsion, especially when used immediately. 
Six pounds of zamia ‘“‘roots” were washed and grated. The pulp 
boiled an hour in 3 gallons of water; then strained, and while hot stirred 
in 4 ounces sal-soda. This emulsified 1 gallon kerosene, forming a bean- 
tiful pinkish jelly, containing 25 per cent. kerosene, costing 6 cents per 
gallon. One gallon of this solution was added to 24 gallons of water. 
This emulsion contained 1 per cent. kerosene, and cost 0.24 cents per 
gallon. 
Dextrine, starch, flour, mucilage of bene (sesamum) leaf, mucilage of 
root of Pteris aquilina, and other substances were tried, but proved to 
be of little value. 
Milk emulsions.—By gradually adding, with agitation, one gallon kero- 
sene to one gallon fresh milk, an elegant emulsion was formed that bore 
dilution well, but as fresh milk is often not attainable the condensed milk 
was used, and the following seemed most easily made: 
One part condensed milk dilute with five parts water; to this add 
gradually eight parts kerosene, with vigorous agitation. When the 
kerosene disappears, add three parts water, and agitate till a homo- 
geneous emulsion is formed. 
This is more pleasant to use than soapy solutions, and costs— 
Cents per gallon. 
Standard solution, 50\per cent. kerosene=..- 52. - ee h eee ee ea a ae ee 22 
Wilution A’, 2 percent; kerosene: 2.5. o. asco ose. cone ee serene ean = eee eee 0. 88 
Dilution B’, 1.25 per cent. kerosene..--..---- Oe: UTS Ove coe Soe eee 0.55 
Dilution C4 I per-cent. kerosenes: 2~-2,.52 ho. 2 ene oe see eee eee 0. 44 
Wilntion D, 6.25 per cent. kerosene... 2.222 32 4o--2 - sas esa see tees eee eee 0, 225 
Dilution BH, 5 percent, kerosenes. = 2-25 sas. beset a= -biss oee a ee nee eee 0. 22 
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