SEA TELEPHONES

Pukekohe & Waiuku Times, Volume 6, Issue 251, 16 February 1917, Page 4 (Supplement)

SEA TELEPHONES

A telephone that weighs eight k'Ui dre.j pounds, about the size of a iatge I acking and needs strong currents of elect, i ity lor its operation, ha* been e. n tructed lor telephoning short distan e- thro.igh water, or lor telegraphing d'NtjiKis of from thirty ta lorty n.i.cs under water.

The diaphragm of thq telephone, curr; s;x niug t:> tee tliin pie e of japanned .sheet lucta! that is generally to I e observed in the transmitter and t'.ie re- ( eiver of ordinary telephones, is a great disc of steel, nearly two feet aerobe and almo-t an i.ich in thickness.

By mean;, el this telephon"' it is , o>•ih.c noi; only to telephone short distill -c\ ; ui:d r w:te", but to dele t iceUrgs in the ncighlourbocd of a vessel ami to ditennino the depth of the k C:i bittom.

Viltrations sent from the telephone will return :is e hoc. from llie sea tr:m or from an iceberg, and l»y means in;r tho time, taken for the return of the (><•'.oo ,it U possible to <st : matc very clrsely the distance of an iceberg or of tho bottom.

Tim te'oph" no is t!ie invention of I'riifo-s-jr 1?. A. Fessenden. who devi-cd some of thj most valnablo instruments used i:i v.ire!e>s t legra.phy and other prncti.-al app!i ations of electricity. J Jin instrument is suspended in the wa: or l>y a derrick 011 the ship, and wiies lead a strong current of e'eetri: ity t,> it. 'l'!ii=) power causes tho heavy diaphragm to vibrato at the n'te of about fixe hundred vibrations a swovut, i nd tho water carries those vibra11oiis just as air carries sound waves. At tlie other end of the wires a delicate teli phone, revivor cat dies the vibrations—though better results for long di-t:iii'-e.-» are obtained bv catching the vibrations in another big re eiving apparatus dc\iej for that puipose.