My attention was attracted to potash salts as an insecticide, by the casual remark of an intelligent farmer, that washing his young pear trees with a muriate of potash solution cleared them of scales. The value of this substance for insecticide purposes, should its powers be sufficient, struck me at once, and I began investigation. It was unluckily too late in the season for field experiments of the nature desired; but it is the uniform testimony of farmers who have used either the muriate or the kainit in the cornfields, that they have there no trouble with grubs or cut worms. Mr. E.B. Voorhees, the senior chemist of the station, assures me that on his father's farm the fields were badly infested, and replanting cornhills killed by grubs or wire worms was a recognized part of the programme. Since using the potash salts, however, they have had absolutely no trouble, and even their previously worst-infested fields show no further trace of injury. The same testimony comes from others, and I feel safe in recommending these salts, preferably kainit, to those who are troubled with cut worms or wire worms in corn. EXPERIMENTS. A lot of wire worms (_Iulus_ sp.) brought in from potato hills were put into a tin can with about three inches of soil and some potato cuttings, and the soil was thoroughly moistened with kainit, one ounce to one pint of water. Next morning all the specimens were dead. A check lot in another can, moistened with water only, were healthy and lived for some days afterward. A number of cabbage maggots placed on the soil impregnated with the solution died within twelve hours. To test its actual killing power, used the solution, one ounce kainit to one pint water, to spray a rose bush badly infested with plant lice. Effect, all the lice dead ten hours later; the younger forms were dropping within an hour. Sprayed several heads of wheat with the solution, and within three hours all the aphides infesting them were dead. Some experiments on hairy caterpillars resulted unsatisfactorily, the hair serving as a perfect protection against the spray, even from the atomizer. To test its effect on the foliage, sprayed some tender shoots of rose and grape leaves, blossoms, and clusters of young fruit. No bad effect observable 24 hours later. There was on some of the leaves a fine glaze of salt crystals, and a decided salt taste was manifest on all. Muriate of potash of the same strength was tested as follows: Sprayed on some greenhouse camellias badly infested by mealy bugs, it killed nearly all within three hours, and six hours later not a living insect was found. The plants were entirely uninjured by the application.