Page:Popular Science Monthly Volume 92.djvu/370

 Safety-First in Mine-Sweeping

How it is secured with a recently- invented Swedish under-water kite

The dangerous occupation of sweeping the sea for mines charged with from four hundred to nine hundred pounds of T. N. T. has been rendered less hazardous by the invention of an under-water kite which first gently touches a mine and signals to the officers on board the ship

DRAGGING the sea for mines, charged with from four hundred to nine hundred pounds of T. N. T. and liable to explode when a little glass tube of acid is broken, is probably the most dangerous occupation in which a brave man can engage. It has not even the redeeming feature of being romantically interesting. There is no chance to fight — only the chance to die an instantaneous death.

As might be supposed, the mine-sweeper drags the waters of the sea with a cable. But the

Attaching cable

Arrow-shaped control

The Under-Water Kite and How It Works

Beneath the roof-shaped kite, an arrow-shaped control is sus- pended by three small wires. When the two forward wires of the arrow-shaped control re- lease a latch by which the at- taching cable is secured to the kite, a bell is rung on board the ship, indicating that the entire apparatus has come in contact with a mine to be removed.

��cable alone is not enough. An auxiliary signaling de- vice is also found neces- sary, something which will indicate the presence of a mine before the actual dragging begins. To this end, a Swedish tell-tale, recently in- vented, is employed in nearly every navy and particularly in the Ger- man navy.

The tell-tale may be described in a general way as an under-water kite which is dragged by means of a steel cable which is paid out from a drum on the stern of a vessel. As the ac-

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