Page:Popular Science Monthly Volume 90.djvu/745

 Popular Science Monthly

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���What's a Dreadnought? And the Purpose of a Dreadnought?

IX these days of stirring events and na- tion-wide discussions of preparedness, naval terms are frequently confused in ordinary conversation.

It is generally known that the displace- ment of battleships — that is, their actual weight in tons — has increased by leaps and bounds from the original five or six thousand tons to the present day battleships of up- wards of thirty thou- sand tons. The term "dreadnought," how- ever, did not come into use until 1906, when the British Ad- miralty evolved what is known as the first all big gun ship. Prior to that time nearly all battleships were armed with four large guns of ten, twelve and sometimes thir- teen-inch caliber, and from twelve to four- teen smaller guns, var>'ing in diameter from six to nine inches. The British Admiralty adopted the bold plan of building a vessel armed with a main bat- tery of ten 12-inch guns and no guns of smaller caliber. This vessel was named the "Dread- nought," and hence became the forebear of the type of ships armed with big guns exclusively. The departure was copied by all the great naval powers, and the race in size and number of guns has gone on uninterrupt- edly, so that this countr>^ now is building battleships like the "Mississippi" of 32,000 tons dis- placement and armed with twelve 14-inch guns. A new term has been found necessar\- in the pop- ular mind to describe these leviathans of over 25.000 tons; they are called "super- dreadnoughts." Battleships built just be- fore the time of the "dreadnought," but which did not carry all big guns in their main batteries, are termed "pre-dread- noughts." "Battle cruisers" while not so heavily armored as dreadnoughts possess much greater speed.

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��A Non-Skid Automobile Device Without Chains

NEW non-skid device consists of two prong-like bars attached to the rear axle of the automobile and operated by a hand lever at the driver's seat. The prongs are mounted in ball-and-socket joints in clamps around the axle between the spring fastenings and the brake drums. When out of action the prongs are held 1 horizontally and entireh' out of contact with the ground. Should the vehicle be- gin to skid, they may be revolved and thus brought down into con- tact with the ground and against the tires. Each prong is made of two parts. The flat but narrow bot- tom shoe -like por- tion telescopes

��The non-skid device is compKjsed of two bars attached to the rear axle and controlled by a spring

��/^DIRECTION OF 5WD

����The two prong-like bars are op>erated by a hand lever at the driver's seat

��SKJD3H0EINC0KTACr WITH TIRE.

How the device works when the vehicle begins to skid

��into the upper end and has a certain upward movement when a spring in the telescoping section is compressed.

The prongs are lowered when the vehicle begins to skid. The one on the side toward which the vehicle is skidding, swings in- wardly to an inoperative position due to the ball-and-socket joint and the yielding shoe. That on the other side, however, comes in contact with the tire. As the shoe scrapes over the ground the tire forms a buffer until the vehicle's side motion is stopp>ed. The shoe is forced out- wardly against the tire by a spring-retained lever pressing against the upper part of the prong. The yielding shoe serves to pro- tect the prong from injury should it hap- pen to strike on a street car rail. Other- wise the skidding momentum might be sufficient to break it.

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