Show THE scientific TESTS it seems impossible that there can be any fault in the atlantic cable when the great eastern goes to sea to say nothing of the tests applied to it atthe at the manufactory it is tested not alone after it has been taken on board but during its delivery into the ship As soon as a length is brought alongside one end is connected with the coils already on board baard and the other end with the thet instruments in the testing room the circuit is thus made through the tho whole extent of the coil the portion on board and the portion alongside the process of hauling in then commences and the insulation continuo continuously ably ubly 0 observed the instruments in the betin testing groom room record the smallest deviation from absolutely perfect insulation it shall be under stood that an insulation which shall bo quite perfect as an electrician understands the tho word is not attainable A piece e c 0 of metal separated by means of t pl the e purest glass and in the driest atmosphere that can be obtained will if charged with electricity lose that electricity after a time in speaking ate abo k of insulation we must therefore be understood to mean an approximate condition but the approximate in the case of the new atlantic cable comes so i near to perfection that this rough tarry rope is is a scientific wonder i rhe the rho last dying pulsation of the old atlantic cable wigs was forced through it by means of a consisting of two hundred and forty cells the tho submarine telegraph from london to amsterdam is habitually worked with a battery of fifty cells and such a battery is commonly used for the other submarine lines of europe signals have been repeatedly sent through more than thirteen hundred mileson miles of the cable now on board the great eastern by means of one cell celi galvanic currents so feeble feebie that they could not have been felt by the hand and might have been passed pissed harmlessly through a circuit completed by the operators tongue can be used to convey messages along a length of cable that would very nearly stretch from london to st Peters petersburg burgY over needle instruments such as those in ordinary use for land telegraphy a current from one cell would be powerless I 1 to record such faint pulsations of electricity it is necessary to use processor professor thompsons Thomp sons mirror galvanometer this beautiful instrument consists of a mirror about the size of a piece made of microscope glass and so 60 thin that it weighs only a grain oil on the back of this mirror a minute magnet is fixed and thus supplemented it is suspended by a silken libre in the heart of f a coil of wire so that any current passing through the coil deflects the magnet and the mirror along with it A ray of light reflected by tile the mirror falls on oil a scale distant about 18 or 20 inches and reveals its faintest movements diff different erent combinations of these movements represent the different letters of the alphabet and thus the alpar apparently antly erratic wanderings i of a ray of light light are made to convey convoy hit intelligence elli gence genee Anin struL strut ment of this kind is constantly used to test the cable as it is hauled on board and if any fault had existed it could not have passed without detection up to this time when they are on beard board the ship and alongside 1970 miles of cable eabie no fault has been discovered |