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2. NEW INSECTICIDES AND MODIFICATIONS OF OLD ONES. 



Some opportunity has ofifered duriug the past year to experiment 

 with one or two new invseeticides, 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 jiatented 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, nonpatented insecticides. 



The cotnhi nation l-erosene 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 Dealing 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, while 

 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 

 intiuence 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 



