122 Report oF THE CHEMIST OF THE 
THE COMPOSITION OF COMMERCIAL SOAPS IN 
RELATION TO SPRAYING.* 
L. L. VAN SLYKE AND F.. A. URNER. 
SUMMARY. 
1. Object—The object of the work discussed in this bulletin 
was to ascertain why commercial whale-oil soaps in some cases 
fail to detroy insects and in some cases cause injury of foliage. 
2. What a Soap is.—A soap is made by treating a fat or oil 
with an alkali, as caustic soda or potash. A soap is a chemical - 
compound formed by the union of an alkali and the fatty acid 
or acids contained in a fat or oil. 
3. Results of Analysis of Convmercial Whale-Oil Soap.—tThe 
important constituents of a soap in relation to spraying are (a) 
water, (b) actual soap, and (c) free alkali. In the case of nine 
samples of commercial whale oil soap, the percentage of water 
varied from about 11 to 55 per ct.; of actual soap from about 
15 to 60 per ct.; of free alkali from nothing to 1.30 per ct. 
Two different lots of soap from the same factory contained 36.79 
and 53.13 per ct. of water and 24.06 and 46.28 per ct. of actual 
soap. 
4. Results of Variation in Composition of Commercial Whale- 
Oil Soaps.—In making solutions of different commercial whale- 
oil soaps, one can not be sure of having a uniform strength of 
solution and this lack of uniformity seriously affects their value 
for spraying purposes. 
5. Home-manufacture of Fish-Oil Soap.—In order to have a 
soap of uniform composition, the following formula may be sug- 
gested: Caustic soda, 6 pounds; fish oil, 22 pounds; water, 1144 
gallons. This will make 40 pounds of soap. Certain precautions 
given in detail in the text of the bulletin should be carefully 
observed. 
*Reprint of Bulletin No. 257. 
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