Show tito II 11 A valuable apparatus for or const coast defense and lliso also for the defense of L has a a been brou brought glit irto into practical ohn gland its ts object is 13 to gi vo warning OT oatho the approach ui ax V t mn consist ns tho 0 night or in a fogs fog it consists of cf an instrument resembling it a microphone this instrument is placed twide an iron di diving yin 9 bell and suspended in the wint water erat at a convell beut depth the electric wires wire from the ln ill are led to stat tons ions on oil tile the coast or or on board the battleship and variations in the current can lie be indicated in a suitable way when a ship approve approaches lles within the range ran go of a mile of t the lie instrument the bibra eions of its engines and the motion of the propellers produce a corresponding tion lion iu in llio abo diaphragm this vibration in the diaphragm is ii used to produce a variation in the electric current which in its turn indicates the vibrations on the stati station oll tho the industrial world thinks that tile hie applicability of this instrument is very wide and it r will prove useful in the merchant service for the object of informing the coast guard of 0 the approach of it a tiner to the during the tog fog |