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2. NEW INSECTICIDES AND MODIFICATIONS OF OLD ONES. 
Some opportunity has offered during the past year to experiment 
with one or two new insecticides, or new methods of combining old ones; 
also with some new combinations of insecticides and fungicides. I will 
not take time to refer to the host of patented articles which are con- 
stantly coming to the Department and being advertised in the agricul- 
tural journals, and which are all, so far as my experience and that of the 
Department goes, very much inferior to the standard mixtures, more 
expensive, and the best of them are merely more or less close copies of 
common, noupatented insecticides. 
The combination kerosene and water pump. — This apparatus, which is 
doubtless familiar to all of you and which was designed by Prof. E. S. 
Goff. of the Wisconsin station, has lately been put on the market by 
the Deming Company in the form of the perfected Galloway Knap- 
sack Sprayer, with kerosene attachment. Mr. H. E. Weed has care- 
fully described this apparatus with figures in Bulletin 30 of the Mis- 
sissippi station. He reports very favorably as to the results of this 
means of mechanically mixing kerosene and water. Eecognizing the 
importance of this method, should it prove to have the merit claimed 
for it, a number of experiments were made in the Department grounds 
applying the spray to the foliage of various plants. The results of this 
treatment were not as satisfactory as they have been reported elsewhere, 
and in the case of several plants very serious scalding resulted, \\ hile 
others sprayed at the same time, or with scarcely an interval between, 
presented no injury. This led to a suspicion of irregularity in the 
output of kerosene, and tests were made to determine this point. The 
apparatus was in first-class condition and the stopcocks worked satis- 
factorily, as shown by the fact that either pure water or pure oil could 
be sprayed by closing one or the other of the valves. It was early 
found that the relative fullness of the water and oil reservoirs had an 
influence on the result, and as the water became low very much more 
oil came out than when the water tank was half or more full. In the 
following tests the spray was directed into graduated jars, filling one 
after the other in each series, without any interval between. The oil 
separated practically entirely in from ten to fifteen minutes, the water 
retaining, however, for some hours a slight milkiness, due to the reten- 
tion of a very small percentage (a fraction of 1 per cent) of oil in sus- 
pension. The separation, however, began immediately, and was rapid 
in proportion to the percentage of oil. When first sprayed into the 
jars the mixture had the appearance of an almost perfect emulsion, 
and the oil was undoubtedly well and thoroughly broken up, and in 
this respect the success of the apparatus can not be questioned. In the 
first two series of experiments the oil tank was practically air-tight, as 
shown by the fact that when the cap was removed the rush of air 
indicated a partial vacuum. To determine whether this had any effect 
