SCIENCE SIFTINGS

New Zealand Tablet, 14 August 1919, Page 46

SCIENCE SIFTINGS

(By "Volt.")

Torpedoes’ “Ears/’

Torpedoes are made in two sizes lßin and 21in—this being the diameter at the middle, —weigh about 28cwt, and cost £IOOO, roughly speaking. In the “business end” of the torpedo is placed 2501 b of guncotton, which is detonated on the missile’s striking the object at which it is aimed. Behind the “charge” is a chamber containing air compressed to a pressure of 13701 b to the square inch ; behind this is a contrivance to heat the air in order to increase this pressure. A gyroscope is placed aboard to correct the tendency of the weapon of alternately riding above and beneath the waters and to keep it at the correct depth lsft under. A delicate instrument, called a microphone, “hears” the sound of the propellers of the enemy ship and controls the torpedo’s rudder, causing her to follow any manoeuvres of her victim.

New Naval Wonder.

The first of a new type of “mystery ship” for the Admiralty has been completed at Southwick, near Brighton (states the Daily Mail). It has taken some months to construct, and the cost approaches £1,000,000 for each “ship.” Altogether six are to he built. Unlike the mystery ships built during the war, these are not intended for destruction, but for salving merchant. vessels sunk by Hun submarines round our coasts. The positions of these merchantmen have been ascertained by the Admiralty Salvage Department, and divers have reported that in many cases they can be raised and fitted again for service. The new salvage ships look like segmented towers, _ with broad shipshaped bases. They rise tier on tier, like a wedding cake, each tier diminishing in size to the top one, which is over 100 ft above the base. Each tier is made of numerous blocks of concrete, honeycombed to withstand external pressure, but otherwise hollow. There are watertight doors, by which the blocks can be filled with water, and pumps by which the water can be replaced by air. These concrete tower ships, which have no motive power, are to be towed in pairs to the neighborhood of sunk merchantmen. On a calm day the hollow concrete blocks will be flooded and the tower ships will be sunk on each side of the wreck. Divers will lash them to the wreck, the water will be pumped out of the blocks, and if all goes well, the tower ships will rise, bringing the wreck to the surface. The construction of the mystery ships has provided a new industry for Brighton. Many- hundreds of men have been employed, and shipyards have been constructed where formerly were only mudflats and a tidal estuary.