Paris Green

a noted insect poison. The active principle is arsenic, but the compound is a green powder composed of copper, arsenic, oxygen, and hydrogen. Eaten by insects it causes their death. In a modified form the mixture has long been used to give paint a vivid green color and in printing the green figures on wallpaper. Europeans knew that it would kill insects, but they made little use of it for that purpose. When the Colorado potato beetle began its ravages in the United States, 1865-70, Dr. Riley of the department of agriculture and other investigators recommended fighting the pest with paris green. Two million pounds are now used annually for that purpose. In use, the powder is first dissolved in water, a half pound or more to the barrel, and is applied as a spray. The fine particles of arsenic lodge on the tender leaves and are eaten by the insects. In an hour or two the potato bugs may drop to the ground dead. Without the aid of paris green the potato raiser would be almost helpless. Paris green and other poisons are used also by fruit growers. See Spraying; Bordeaux Mixture; Potato Beetle