History of the Atlantic Cable & Undersea Communications
from the first submarine cable of 1850 to the worldwide fiber optic network

1884 Mackay-Bennett Atlantic Cables
Manufacture

In 1884 the Commercial Cable Company commissioned Siemens Brothers of London to manufacture and lay two Atlantic cables. The Pall Mall Gazette had this report on the manufacture at the Siemens cable works on the Thames near Greenwich:

MAKING THE NEW CABLE.
TWO THOUSAND MILES ALREADY MADE
THIRTY MILES PRODUCED EACH DAY

From the Pall Mall Gazette, April 10, 1884.

The New-York Herald has proved itself more accurate at prophecy than Mr. President Pender, Cable King on this side though he be. It is not so many months since Mr. Pender congratulated the Atlantic cable companies on "freedom from the dread of more cables,” at least for some considerable period. On the other band, the Herald, for a somewhat longer time, has been persistently promising that, as a result of the irritating monopoly of Mr. Jay Gould, an early Summer would see another cable laid across the Western ocean. Thanks to the courtesy of Mr. Gordon Bennett, conveyed through his London representative, Mr. P. M. Potter, we were enabled the other day to witness the making of the cable, or, rather, couple of cables, in course of manufacture by Messrs. Siemens for the Mackay-Bennett combination, and within the next week or two the Faraday will have started afresh, with 1,500 miles of cable on board, on her mission of cable laying between Dover Bay and Valentia.

Going to Messrs. Siemens's works, you land at the little station of Charlton, one station in advance of Woolwich, and a walk of half a mile or thereabout amid Black Country surroundings brings you to the imposing-looking manufactory. Here more than 2,500 men and lads are employed, quite 1,700 of whom are engaged upon cable work. Our object was to see “how the cable is made,” so to this business the relation of our visit to Messrs. Siemens's extensive works must on this occasion be confined. A cable, the visitor soon learns, is marked throughout its length by several variations of diameter, fixed to meet the varying circumstances of the ocean bottom, although the constituent formation of the cable has always remained the same. When once laid down in deep water, cables are in no serious danger—the temperature, the chemical qualities of the sea and bottom, and the movement of the water exercise next to no influence upon them, and if well-made cables be properly laid, cable authorities now acknowledge there is no reason why any short estimate of their life should be formed. The shore ends, as everybody knows, are necessarily built much thicker than the body of the cable; but even shore side are only subject to “chafe,” and a shore end, a competent judge tells us, ought to last from 30 to 40 years. Three sections of the cable in process of manufacture are placed in our hands, as we start upon our tour of examination, by an intelligent cicerone, Mr. Schramm, who has had a long experience in cable manufacture and cable laying. The first is a section of shore line; this is 2½ inches in diameter, which is the maximum diameter of the cable. The other sample is a section of the great body of the cable; this is 1 inch across, which is the minimum diameter. The third serves as a type of the links which connect the shore ends and the deep sea portions of the cable. To assist to a comparison of size we may mention that an ordinary land line is two-tenths of an inch in diameter.

Armed thus, we begin our inspection, with the reminder that the broad principles which were observed in the construction of the first submarine cable laid down between Dover and Calais in 1851, mark submarine cables yet—in the centre you have the conductor, around it the insulator, and over it, finally, the outer covering. First, we are shown the “copper centre” of the deep-sea part of the cable in process of manufacture. It Is formed of 13 wires—12 wires of small size coiled around one wire one-tenth of an inch in thickness. The conductor thus created is two-tenths of an inch in diameter, or just the size of an ordinary telegraph wire. This work of binding the copper wires together is performed by a small "stranding machine,” which grasps the principal wire as it is driven through an orifice, and fastens the 12 minor wires around it; the operation is as if an unsuspecting traveler, upon making his appearance upon the borderland of a strange country, was suddenly seized and securely bound after the fashion deposed to by Gulliver. All the interstices are afterwards filled up with a solution of gutta percha. There are 10 of these stranding machines at work upon this cable, and these can together turn out 50 miles of copper centre in a day of 24 hours. Breakages of wire are rare. The copper used, of course, is of the best quality, it comes principally from Lake Superior: where this is not so, it is a copper purified by a solution process. Messrs. Siemens generally buy the copper in wire-form. They are now using it at the rate of 40 tons per week. There is more weight of copper in the cable now being manufactured than in any other cable previously turned out.

Glancing upward as we leave the sheathing department, we observe the cable traveling, away over our heads toward a series of large tanks, in which it is stored until the time arrives for its shipment. In these tanks is coiled some 2,000 miles of cable, the 1,200 miles which the Faraday had on board having been all coiled back into the tanks when she returned into the river after the accident which has caused the long delay in the laying of the cable, and nearly 1,000 miles of “core” is ready, in addition to this amount of completed cable. There are four tanks, 30 feet diameter and 15 feet deep, which will each hold 200 miles, and six tanks, 40 feet diameter and 30 feet deep, which will each hold 400 miles of cable. There are altogether 20 tanks in use at the present time. When necessary for testing purposes these tanks are filled with water from the water company’s main. You have to ascend ladders to reach the platform which overlooks them, and as you glance down upon them you fancy yourself looking into a series of small gasometers. The lime which a man scatters over each layer of cable as it is laid down is the simple expedient employed to prevent it from sticking together. As the cable passes away into the tank you are apt to be much struck by its inflexible bar-like character; but Mr. Schramm will tell you that “when lifted when in a long piece the cable is like a thread of silk.” The coiling, which is marked by great regularity, is done by men stationed within the tanks. While stored in these large tanks, the cable is still kept continually under the electric test. A division of one of the firm’s offices is given up to the testing. apparatus. The principal instrument here, as might be expected, is the wonderful galvanometer, with its small mirror illuminated by a lamp, instantly reporting any failure in the degree of current expected, which, of course, indicates some fault in the construction of the cable. The cable will be worked by the duplex system of telegraphy. But into this department we cannot trespass further at present; perhaps we may be enabled to inspect the working of the cables on board the Faraday.

A few additional words may not be out of place as to the character of the cables thus being turned out for Messrs. Mackay and Bennett. Messrs. Siemens made four of the six Atlantic cables last laid down, so that when it is stated that the cables now in course of manufacture show improvements upon these, it will be inferred that they are the best and dearest cables that so far have been produced. “The more the weight of copper put into a cable,” it is a commonplace in cable-making, "the better the cable.” In these Mackay-Bennett cables the conductor is particularly heavy; while copper wire, it should be remembered, is twice as good as it was 20 or 20 years ago. A cable “conductor” may be compared to a water-pipe—the greater the bore of your pipe the more freely will the water pass through; the greater the “conductor” the more freely are the signals exchanged, and so, it is hoped, it will prove in this case. The average weight of the conductor per nautical mile in these cables is 450 pounds, and the average weight of the gutta percha insulator is 300 pounds, giving a weight of 750 pounds per nautical mile for conductor and insulator together.

As we have before mentioned, considerable attention has been devoted to the wire shield, with a view to obtain greater strength and durability. The breaking strain of the steel wire is about 90 tons to the square inch, which, we believe, is the highest point yet reached by cable manufacturers. The breaking strain is tested by means of specially constructed machines, the increasing power being applied uniformly without jerks or jumps. The average weight of the cable—conductor, insulator, cushion, composition, steel shield—is five tons per nautical mile; shore ends by themselves will sometimes run to 20 tons per mile. The total lengths of cable made will be over 6,000 miles, the cable distance from Dover Bay to Valentia and vice versa being 2,600 miles; the remaining 800 miles will be employed in the making of submarine connections, one of which will run from Dover Bay to Cape Ann. To the already recorded fact that Messrs. Siemens have completed some 2,000 miles of cable, it may be added that they are going on with the work at the rate of 30 miles per day. The Faraday will probably have to make five or six expeditions into the Atlantic over this business of the Mackay-Bennett cables.

The Sandy Bay Historical Society in Rockport has a permanent display on the 1884 Atlantic Cable.

See also this article on the landing of the cable at Cape Ann, near Rockport, Massachusetts, and hydrographer Henry Ash's sketches of the view at Cape Ann from CS Faraday.

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Last revised: 29 October, 2022

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