New York AGRICULTURAL EXPERIMENT STATION. 128 
6. Haperiments in using Home-made Soap in Spraying.—The 
home-made soap, when used at the rate of one pound in seven 
gallons of water, gave entire satisfaction in every way on the 
foliage of apple, pear, plum, currant, cherry and peach trees. The 
foliage was not injured ana plant lice were destroyed. 
7. Experimenis in Spraying with Soap containing Free Alkali. 
—Soaps were made so as to contain 1, 2, 5, 10, 20 and 50 per 
ct. of free alkali. These were used in the same strength of solu- 
tion and on the same kinds of foliage as given above. Injury 
was done when the free alkali reached 10 per ct. Little injury 
was done by the use of soap containing 5 per ct. or less of free 
alkali. 
8. Cost of Home-made Soap.—Caustic soda. can be purchased 
at 414 cents a pound and fish-oil at 26 to 30 cents a gallon. On 
the basis of these figures, the cost of the materials used in making 
one pound of fish-oil soap is about 234 cents. 
9. Advantages of home-made fish-oil soap are (1) greater uni- 
-formity of composition, (2) greater reliability, (3) decreased 
cost. 
INTRODUCTION. 
The work embodied in this bulletin was suggested by the com- 
plaints that have been made in respect to the unsatisfactory re- 
sults frequently experienced in the use of so-called whale-oil soap 
when used on orchards for the purpose of destroying certain 
forms of insects. The disappointing results reported vary in 
character; in some cases the insects are only incompletely des- 
troyed; in other cases, the foliage is killed and the trees also. 
The uncertainty of the results of applying this remedy has 
caused no little uneasiness among fruit growers and numerous 
letters have come to this Station asking for information in regard 
to the use of whale-oil soap. As a result of this condition, the 
Station entomologist, Mr. P. J. Parrott, suggested that we take 
up the subject for investigation. 
There are on the market many different brands of whale-oil 
soap, and it occurred to us that there must be marked variations 
in the character of different brands to account for the great differ- 
ence reported in the results of their use. There is no known rec- 
ognized standard of composition for this class of soaps and, as a 
starting point of our investigation, it seemed necessary to obtain 
