Page:Popular Science Monthly Volume 3.djvu/53

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Every word of this can be written at the present moment, that is, ten years later, with exactly the same significance. All cables which have been manufactured and laid upon the principles which were established in 1859 are yet in good working order, and every divergence from these principles has been at best but a costly experiment or utter failure. There is no instance yet of a well-manufactured heavy cable breaking or giving out in deep water after it has been carefully laid free from defects; but there may be much due to the external covering keeping it quiet; there has assuredly been a great deal due to the external covering in the successful submerging, and there is no experience whatever to justify the assumption that an unprotected core would last, even if laid.

It has been urged that an iron-covered cable, suspended from one point to another, gradually becomes weaker, that rust and marine growth or deposit accumulate and break the cable with their weight; but I do not know of any instance in support of the assumption, nor is it at all certain that a simple unprotected core would exist for any length of time, or be in any way better adapted for the supposed conditions. Mr. Latimer Clark, in his evidence, says: "You want a certain degree of weight to enable your cable to sink steadily to the bottom, especially when it has to fall into hollows and cavities, and not lie loosely across elevations."

Again, it is urged that experiments with light cables have been tried in factories or sheds, and the result proves that there are many advantages in their favor; but I am of opinion that no experiments which can be made on shore will sufficiently resemble the exigencies which may occur over a period of several days and nights at sea in storms and darkness, and still less will they prove their fitness for the unknown conditions which may exist at great ocean-depths. I desire to write with great respect for the opinions of the talented men who urge the adoption of light cables; it is my special duty to weigh well and without prejudice all they have to advance; but I think a careful investigation into the experience and practice of the last twenty years establishes conclusively that all light cables have been short-lived, and that all heavy cables have continued working, often under most adverse conditions. It is my own opinion, and I am authorized to say that it is also the opinion of my friend Captain Halpin, who has laid all the cables from Suez to Australia, besides the French Atlantic cable (11,000 miles), and has also recovered and repaired cables from a great variety of depths, that a cable should be as heavy as it can be laid with safety, and admit of being recovered in case of accident. Multiply every precaution which shall increase the strength and keep that strength intact as long as possible.

The best form of light cable I have seen is the copper-covered core invented by Mr. Siemens (No. 8). I should have anticipated that, if any light cable could have been successful, this one would have met