44 THE POPULAR SCIENCE MONTHLY. 



all the conditions, excepting that of extreme cheapness, but it has not 

 been so uniformly successful as the heavy iron-clad cables. The very 

 light cable invented by Mr. Varley (No. 21) admits of being laid by 

 having the strain taken off the core by the two hempen strands, the 

 core itself beinGf the third strand of the cable. As a liadit cable, to be 

 manufactured in a great hurry, and laid to meet some emergency, it 

 has a good deal of merit, but for a deep-sea cable I am. of opinion that 

 it would be found too incomplete and unfinished, and that difficulties 

 would be experienced in laying which are not at once foreseen, and 

 that there would be no durability even if successfully laid. 



Every day of my experience in watching over the permanence of 

 the 10,000 miles of cable under my care, confirms me in the opinion 

 that too great caution and vigilance cannot be exercised in the making 

 and laying a thread which is to be removed from all human vision for- 

 ever, and designed to earn dividends by continuing a perfect conductor 

 of electricity. Upward of 30,000 miles of cable have been laid since 

 the report of the committee was printed, eleven years ago, and much 

 experience has been gained of the exigencies incidental to submerging, 

 buoying, grappling, and repairing ; but no fact has resulted from all 

 that experience which has established that any one precaution recom- 

 mended in the report has been superfluous, whereas much has occurred, 

 which I will not particularize, proving that any attempt to disregard 

 any single precaution has resulted in great pecuniary loss or utter 

 failure. 



We have many reasons to confirm the belief that a submarine 

 cable, manufactured and laid with strict attention to all known princi- 

 ples, may be regarded as a substantial property, likely to last for any 

 length of time; for there is no evidence whatever upon record which 

 shows any decay of the insulating medium or copper conductor of a 

 well-manufactured cable, i. e., there is no decay inherent in the nature 

 of a cable ; all deterioration is external ; nor is there any experience 

 whatever to establish that this insulated copper wire will enjoy any 

 durability if unprotected with an external covering. 



A light cable or unprotected core must therefore be regarded at 

 best as an experiment, with the chances against the successful laying, 

 and still more against its existing as a permanent property. 



I have written enough to illustrate that the present submarine 

 cable is not a haphazard idea, but one which has grown out of many 

 failures and thousands of experiments; all the principles of manufac- 

 ture and laying down have been established by great anxiety and re- 

 flection on the part of the able men who gave their energies to this 

 kind of enterprise prior to 1865. We who have come upon the stage 

 since that date have only discovered that we may not neglect one of 

 all the known principles, but elaborate every one of them, and even 

 then the duty of laying and maintaining this class of property has 

 enough of risks and anxieties to make one heartily dislike any experi- 



