Page:Popular Science Monthly Volume 88.djvu/763

 Popular Science Monthly

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��Poison Gas forAmerican Pests

GAS that is far deadlier than the poison gases that are used on the battle- fields of Europe is employed daily in America for pur- poses of stamping- out pes- tilential beetles, moths, and vermin of all kinds. Hydro- cyanic acid gas will kill a man if he inhales a single lungful. Yet its deadliness, when controlled by man ami directed against his many small destructive enemies, is so desirable that the Depart- ment of Agriculture has is- sued an order requiring cit- rus crop growers in Califor- nia to apply it to their plants to combat scale, the mealy bug and similar destroyers.

The gas is produced by dropping tab- lets or measured amounts of cyanide of sodium into sulphuric acid. The room in which the gas is generated is well sealed. Different plants require differ- ent amounts of the gas for thorough fu-

A Fire-Fighting TroUey-Car

DULUTH has a fire-fighting trolley- car which is used for detached sub- urbs where poor roads or other barriers prevent ready response by motor or horse equipment to alarms of fire. The harbor of Duluth is formed by a narrow

���Preparing

���A suburban fire department which finds an old street- car an efficient motor fire-engine

��to rid a greenhouse of insect pests by means of deadly gas

migation, the dose of sodium cyanide varying from five ten-thousandths to five thousandths of an ounce per cubic foot of air space. The former amount is sufficient to kill ordinary green flies; the latter will deal death to sow bugs.

strip of land extending across the west- ern end of Lake Superior. This strip of land, four hundred to six hundred feet in width, extends for a distance of seven miles from the jMinnesota to the Wisconsin shore. About three miles of it, extending from the Duluth shore, is built up with summer houses and perma- nent residences of expensive construction. This suburb, Park Point, is so narrow that only one street is laid out, and on this street the track is laid.

The city purchased a streetcar which had out- lived its usefulness, but which was still in fairly good condition. After the seats were removed a hose-box was installed the whole length of the car and left open at both ends, so that no matter in which direction the car is going, it can carry the hose line from the hydrant to the place where the fire is located.

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