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Three fertilizers were applied: superphosphates, muriate of 
potash, and sulphate of potash, each at the rate of three pounds 
to twenty hills of corn, and in each case half the hills under ex¬ 
periment were treated with the pure fertilizer and the other half 
with a mixture of fifteen ounces of petroleum to three pounds. 
One third of the above amounts were applied June 18,—the 
petroleum in these cases being the crude Lima oil,—and the re¬ 
maining two thirds, June 23, when refined petroleum was used. 
The following notes are condensed from the memorandum filed 
at the time by the assistant* in charge of the experiment: 
Experiment I., Superphosphates. Experiment II,, Superphosphates and Petroleum. 
June 29, I. Ants and root lice numerous. 
• ‘ 29, II. Both insects present, but less numerous than in 1. 
July 1, I. Ants and lice abundant. 
‘ ‘ 1, II. Ants present but no lice. 
“ 7, I. Ants and lice abundant. 
“ 7, II. A few ants but no lice. 
“ 15, I. Ants and lice comparatively abundant. 
‘ ‘ 15, II. Ants and lice both present but fewer than in I. 
Experiment III., Muriate of Potash. Experiment IV., Muriate of Potash and Petroleum. 
June 29, III. A few ants and lice found. 
• ‘ 29, IV. Dead plane lice discovered in one hill, both ants and lice occunng gen¬ 
erally but not abundantly. 
July 1, III. A few ants but no lice. „ , „ A1 . 
“ 1, IV. Ants alone discovered on roots about one foot from the hill, just out¬ 
side the fertilized area. 
‘ ‘ 7, III. Ants and root lice found. 
“ 7, IV. Ants but no lice. 
“ 15,111. Ants plentiful: lice common. 
‘ ‘ 15, IV. Few ants and lice detected. 
Experiment V., Sulphate of Potash. Experiment VI„ Sulphate of Potatsh and Petro¬ 
leum. 
June 29, V. Ants present but no lice. 
“ 29, V[. A few ants present but no lice. 
July 1, V. Neither ants nor lice were found. 
V 1, VI. A few ants and lice in one hill. 
' “ 7, V. Ants and lice numerous. 
“ 7, VI. Both insects present. 
“ 15, V. No ants or lice detected. 
‘ ‘ 15, VI. Small colony of ants and a few lice in one hill. 
The weather during the period covered by the above experi¬ 
ment was generally dry, but abundant, rains occurred June 20 
and 21, which seemed to dissolve the fertilizers and wash them 
into the ground. 
The lime, ashes, and salt experiments were entirely without 
effect, ants and plant lice occurring abundantly in all parts of 
the plot treated throughout the entire period of observation to 
July 28. This plot served consequently as a check upon the 
preceding experiment. 
Although the effect of the other applications seems from the 
above notice to be quite marked, the experiment is nevertheless 
indecisive, since the hills treated were not dug up when examined 
from time to time, but only searched as carefully as was pos¬ 
sible without injuring the plants. July 28, when all the hills 
were removed they seemed, according to Mr. Marten’s report, to 
be about equally infested, all appearance of difference having 
then vanished. It will thus be seen that these experiments have 
little value except as hints towards future work. The differences 
* Mr. J. S. Terrill, now of the Agricultural Experiment Station of Kentucky. The work 
was, however, done under the immediate supervision of John Marten, one of my present 
entomological assistants. 
