Page:Popular Science Monthly Volume 89.djvu/197

 Popular Science Monflihf

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��Boy's Road Wagon is a Real Loco- motive

MECHANIC

in a garage machine-shop in Eugene, Oregon, wanted his bo\' to know something about the mechan- ics of a locomotive, and in his spare moments construc- ted the machine in the accompanying illustration. It is a perfect miniature of a large steam engine, and is complete in evcr>- detail. It carries a pressure of steam up to fort\-fi\'e pounds, and pulls the tractor with two passengers at a speed equal to a fast walking gait.

The engineer and owner is a boy nine years old, and he has already obtained a remarkable knowledge of the actual working of a steam locomotive from the operation of his little machine. The engine burns coal, pitch-knots, and small pieces of bark and wood

���The locomotive with the engineer in over- alls and his trusty fireman behind him

��A Cane to Help the Conva- lescent Soldier

ACAXE intended to make walking easier for the convalescent soldier has found popularit}' in England where ever\' ship from the war zone brings wounded men still too weak to walk great distances but sufficiently recovered to be about. It is of stout con- struction. It has a curved handle and is fitted with a rubber tip so that it is a safe support when traversing slippery pave- ments. The unique feature of its con- stniction is a fold- ing foot-support which opens on the principle of a knife- blade, a few inches from the bottom. This the soldier uses as a rest.

���How the cane foot-support assists the soldier in walking

��Wind Cave Excels

Mammoth

Cave

WIXD CAVE. National Park, in the Black Hills, about twelve miles from Hot Springs, is on the Deadwood - Denver scenic highway — • the "Triangle D" road of the West. Wind Cave enthusiasts claim that this cavern excels the Mammoth Cave of Kentucky in splendors and in extent. Half a dozen government surveys have been made in the park. These and various private exploring expeditions that ha\'e been organized have accounted for some 96 miles of the recesses of Wind Cave, but there are hundreds of passageways that have never been ex- plored. No one knows to what depths they lead, or how far under the Black Hills they maj' take the explorer. The average visitor to Wind Cave, National Park, trav- els from six to ten mites un- derground and comes forth into the daylight realizing that he had seen but a small fraction of thisgreatca\'ern. Wind Cave takes its name from the strong cur- rent of air which almost constantly surges in or out of the entrance. It is said that this led to the dis- covery of the cave in 1881. Many explanations as to this mysterious rush of air at the entrance to Wind Cave have been advanced. Some have claimed that the rise and fall of mysteri- ous lakes, many hundreds of feet underground, where no exploring party has yet penetrated, are the cause of these air currents. A more generalK' accepted theory, howe\'er, is that the air pressure outside is the cause of it all. The cave is a huge barometer, respond- ing to every change.

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