Ml*. J. N. Hearder on the Atlantic Cable. 41 



Bearing in mind the tiny character of the Atlantic wire, one 

 is irresistibly led to inquire what end such a battery as this was 

 destined to accomplish, and whether the same end might not 

 have been attained by much smaller means. 



Its object, then, is not to generate a current of electricity to 

 be passed through the cable, but through the primary wires of 

 the induction coil, in order to excite magnetism in its iron core ; 

 and it is the magnetism thus excited which has to react upon 

 the secondary coil, and generate the current of electricity which 

 is to be employed for working through the cable. The electrician 

 will not fail here to predicate many chances of loss of power, if 

 the conditions requisite for developing the greatest amount of 

 magnetic power in the iron core, as well as for turning to the 

 best account the magnetism thus obtained in the production of 

 a secoudaiy current, be not observed. The effects at present 

 produced by these induction coils, as I have before remarked, 

 indicate serious losses somewhere ; but whether they arise from a 

 faulty principle or defective workmanship, is a problem yet to 

 be solved. I cannot conclude this paper without offering an 

 opinion or two on the present cause of failure of the Atlantic 

 Cable, and the ultimate prospect of success. Had the cable been 

 tested in water, after completion, which might have been readily 

 done at Keyham Dockyard, defects might have been easily dis- 

 covered and repaired. The omission of this test leaves much 

 room for speculation as to the cause or seat of the injuries or 

 defects. I have no faith in the modes which have been adopted 

 to discover their situation, so far as I have become acquainted with 

 them, though I believe that the proximate determination of these 

 particulars is still attainable. A consideration of the mechanical 

 construction of the cable shows that it is very liable to injury in 

 the process of laying. I have seen some specimens recovered after 

 immersion, which were kinked in such a manner as to strain and 

 injure very materially the gutta-percha coating of the conductor, 

 which having nothing but its own tenacity to depend upon, would 

 be subject to enormous tension by the lengthening of the external 

 iron covering. With electricity of such high tension as that 

 required to work through the wire, the smallest fissure or defect 

 in the insulating coating would form a leak of a much more 

 formidable character than if it existed in a wire of moderate 

 length ; and the fact of working to eai'th increases the tendency 

 to lateral discharge. If, however, the faults be not discovered 

 and remedied, the cable, although useless for the purpose for 

 which it was originally intended, may still render valuable assist- 

 ance to the success of future lines by being employed as a wire 

 for the return current, instead of enipluyiug the ordinary mode 

 of working to earth — a practice which appears to mc, in relation 



