MAGNETIC MINES

Patea Mail, 8 January 1940, Page 4

MAGNETIC MINES

LATEST NAZI WEAPON HOW THEY ARE OPERATED The Controller of Censorship, Sir Walter Mouckto'u, has ordered an inquiry linto an alleged leakage of naval information to America, revealing that the cruiser Belfast was holed by a mine or a torpedd in the Firth of Forth recently. The (inventor of Hie mine, Herr Bergestroem unsuccessfully tried to sell his patent to -Sweden and Germany, but British men who served in minc-swoepers towards the end of t. e last war assert that Germany was then using a similar mine, which has now been greatly improved. They explain that the mine is exploded by a minute needle displaced when attracted by a ship passing over it. Even when the mine is moored fom or five fathoms beneath the surface, it is unnecessary' for the mine to make contact with the hull.

. Wien the mines arc laid a depth of 40 or 150 feet, and tinyship draws 1:5 .feet, a rending effect is felt all along the heel similar to a depth charge destroying a submarine. The British Admiralty experimented with magnetic mines many years ago, but inasmuch as ( it is not Britain S policy to blow up neutral and noncombatant shipping (he Admiralty d;d not see an important tutuic foi magnetic, mines. Nevertheless the research departments have not been idle. The Navy endorses the broadcast statement by, the Chancellor of the Exchequer, Sir John Simon: <( A11 Cat the skill of science can devise is being devoted to. the new danger, and T am confident that the efforts will be successful.’' A submarine mine-layer can carry 48 magnetic mines. “BUBBLE” MINES FROM PLANES Another new feature of the mine warfare is the sowing of small ‘bubble’, mines from planes, so-called because they -drift visibly on the surface like a largo bubble. .Their weight is about 4901 b. They arc less dangerous than the anchored magnetic mines, because a keen look-out can give warning. ~ The biggest German seaplane might carry seven or eight bubble mines. Inasmuch as they can bo watched oven at night time, as happened on the llmmcs estuary, and the number of mines dropped can be counted prepaiatoij to sweeping, this method is less ad\autageous than sowing from submarines. Nevertheless planes can drop mines close inshore and they do not, run the risk of making contact with mines previously laid. It is doubted whether there is any foundation for stories of the Germans dropping bubble mines by parachute from great heights, because with the urines floating in. the breeze from 110,000 fool, the’ airmen could not bo certain that they would reach navigable waters. They might easily become stranded on a sand-bank or inshore. Germany, despite her protestations as far back as the Hague convention of pin", that she would • observe humanitarian methods of warfare, is now repenting the practice inaugurated a few hoars after the declaration of war in 191-1, when the Koningin Luisc was destroyed while laying 200 mines within HO miles of Gontliwold, Until the end of .the wav Germany continued to lay mines in international waters.

POWERFUL UX'T.C-TVUr; ■There is some speculation regardin'.; the constitution of the mine explosive. As the bubble mines arc small they must contain very powerful ingredients . British authoiilies are reticent regarding the American story Eat Gorman mines, torpedoes and bombs < ontain a tremendous destructive explosive atomite, with, which they experimented successfully in Spain, and which is three times as powerful as TNT. Some experts are sceptical. They consider it more likely Eat the Germans are using TNT or TNT mixed with ammonium nitrate.