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PUBLIC RECORD OFFICE

Reference :-

EPIC.O. 885

6-ALLY WITHOUT PERMISSION OF THE

BE REPRODUCED PHOTOGRAPHIC- COPYRIGHT PHOTOGRAPH—NOT TO

PUBLIC RECORD OFFICE, LONDON

17 November 1896.]

Chairman-continued.

Mr. SIEMENS.

steel we can obtain. As I said already, yesterday, that first contemplated is excep tionally good steel. This plough-rope steel we cannot get in quantities enough for cable manufacture, but that at 96 tons to the square inch is already a very good quality steel. Then for all the other types we take soft steel. For a time it was usual to take hard steel, for some of the types at least, but curiously enough, soft steel is stronger than hard steel for a pull sideways. Of course you have always to bear in mind when you want to pick up a cable you have to hook it, and have a side- way pull on it, and if you decide to come to our works we would show you those tests with steel wire, which is very much stronger if you have a direct pull on it, hard steel wire, which is very much stronger than soft steel wire; but when you support it horizontally, and hang a weight to it in the middle, it cannot support as much as a soft steel wire, and therefore for the types which are in comparatively shallow water we use soft steel. Of course tempered steel would be better, but it is very much more expensive than the soft steel, and it would be too good; I mean it is not wanted.

650. Now will you go back for a moment to the conductor; can you describe to the Commit- tee the amount of the material you propose to employ ?--Well, we propose to employ for the long-section conductor→→→

651. That is the deep sea?-No. We take the same conductor right through. It follows, from a mathematical law, that if you take a certain weight of copper in the cable, you get the best conductivity if you distribute the copper entirely evenly over the whole length. We used to follow the usual practice of putting the heavier conductor in the shore ends, but that is really no advantage. Well, for the long section from Vancouver to Fanning Island, we propose a core containing 500 lbs. of copper and 320 lbs. of gutta-percha.

652. Per?-Per nautical mile.

653. And the second section, I think, has got the next biggest core? That is, 170 lbs. of copper per nautical mile and 160 lbs. of gutta-percha, and over the remaining sections, being comparatively short, we take 100 lbs. of copper and 120 lbs. of gutta-percha. Of course all these short sections give a very much greater speed than 15 words.

654. And the ceutral wire of the strand-I see you particularly specify that it shall be drawn through a compound before the other wires are put on?-Before the other wires are put on, yes; that is, to exclude air that might lead to trouble afterwards when the gutta-percha is put on, it might be squeezed out and get into the gutta-percha; therefore it is better to have com- pound on the wires.

655. Now, as regards the dielectric; what is weight of material?—I stated it in describing

the core.

656. You took the two together?-Yes; 500 lbs. of copper and 320 lbs. of gutta- percha.

657. Now, as regards the outer coverings, there you make a distinction between the deep aes cable, the light intermediate, the heavy

[Continued.

Chairman-continued.

intermediate, the light shore ends, and the heavy shore ends ?—Yes.

658. Will you explain to the Committee the differences that you propose ?—I have here all the figures giving the exact data, but I think it is really better to look at these samples. Well, you see I have not filled in, I believe, the figures, and there are three different types, so you must have three different figures. Well, we can put it in, of course.

659. Perhaps you will think that over, and you might send it on afterwards?-Perhaps I had better give you a copy of this afterwards. I mean it is a lot of figures which would not convey the whole effect. The samples are made up in that style the nearer you get to the shore

You

660. This shows the different types ?—I think the deep-sea type is on the table somewhere; it has been taken out of this case. This is the deep-sen type (showing sample of cable), see there the sheathing wires are very thin, and there is a good number of them. This is the next (producing another sample of cable), which is used in water from 400 fathoms and upwards. You see it has a brass tape on to protect the core against "teredos." Four hundred fathoms is about the greatest depth that "teredos" are found, and that is to protect the cables against them. This is (showing a third sample of cable) still more approaching the shore; it is made heavier. And this next type (showing fourth sample of cable), is put where there may be fishing boats or so anchoring. If the shore is sandy and there is not much anchorage in the neighbourhood, you can use that even as a shore end, but if you have to go through anything like anchorage you must make a double sheathing (producing fifth sample of cable), and have an outer sheathing with strands of three wires so as to make the cable mechanically strong-that the small anchors at least cannot break it. All these samples are for the largest core, but for the smaller cores the types are varied in a similar

imanner.

661. Have you anything you wish to add as to the quality of the steel wires, or have you said all you wish to say about that ? No.

I do not think I need add anything more.

662. A question has been asked of Mr. Chamberlain which I should like to put to you. Is it the custom generally to buy these materials from British manufacturers, or have you to go abroad for them?—No, it depends a little on the quantity which is wanted. Sometimes we cannot get the quantity in England, and we have to go abroad; but as a rule we buy all the materials in England, in fact, we cannot get that good steel anywhere else.

663. Now when the cable and its different parts are all ready for laying, what tests do you apply? Oh, the cable is being continually tested while it is being manufactured. The core is made perhaps I may describe that shortly. When the core has been manufactured and has been tested by the hydraulic and by the high tension alternate current, then it is brought into the sheathing department and coated, first with a layer of tanned jute, and from there it passes on to the sheathing machines which lay

17 November 1896.]

Chairman-continued.

Mr. SIEMENS.

the steel wires round, and the outer covering of jute and compound, and while it goes through the sheathing machines the conductor of that core is connected to the testing department, and we have got somebody watching the spot of light which indicates the proper insulation all the time, so that the moment anything happens the machine can be stopped and it can be investigated what it is. From the sheathing machines the cable passes into big tanks where it is kept under water and also continuously tested; or at least, of course, as long as the sheathing machine is going. The cable in the tank, of course, is connected to the same testing instrument as the core which is passing through the sheathing machine, and when the tank has been filled, so that the cable is by itself, then its ends are left out, and it is tested at regular intervals during all the time of the storage, until the ship is ready to take it; a0 that you get a complete set of tests of every drun of core from the time it leaves the gutta- percha shop until it is in the tank, and it is very carefully noted, and the cable is marked outside at the commencenient and the end of each drum of core, and all the core drums are numbered, and the cable in the tank is also described in the records of the business as consisting of core drums numbers so-and-so in the proper order, and then the tests of the completed cable in the tank must agree with the sum of the tests of the core drums which make it up. If they do not there is something wrong, and it has to be investigated. Of course, as I said, these lests are made daily until the cable is put on board the ship, and there, generally, the tanks are bigger than the tanks at the works, and the contents of several tanks are put into one tank on the ship and duly jointed up, and then the same sort of tests are continued on board ship every day, in order to control that nothing un- usual happens. If there is the slightest deviation it can at once be investigated to see what is the

matter.

664. You have described the tests that the cable is put through from its first commence- ment to the finished article; can you tell the

Committee whether these tests have been found in practice to be sufficient -Oh, certainly.

665. Can you tell the Committee whether any, and if so what, interruptions have taken place on cables laid down under similar precautions?- These last precautions of testing with very high tension alternate current we have only applied to two cables yet, and that is the Commercial cable, and the cable in the Amazon River, and neither of them has shown any electrical fault; in fact, I think the Commercial cable, the third 1894 cable, has been the first Atlantic cable that has been laid without any fault at all showing up during the laying or since.

666. The 1894 cable has been laid two years in the Atlantic; how long has the Amazon cable been completed? The Amazon cable has only just been completed-in March last. They have had interruptions; I mean, the trees have torn it up, and so on, but no electrical interruptions whatever have been shown.

667. Have the usual causes of interruptions on cables laid down been traceable either to

Chairman-continued.

[Continued,

the air bubbles or to the foreign substances that you were speaking of just now ?-Yes, if they were electrical faults, but of course there have been cables interrupted by anchors, and that. That I do not count; that you cannot prevent by the manufacture; but electrical faults have developed through air bubbles and dirt, I suppose I should say, which got into the gutta-percha.

668. And extraneous causes such as anchors- are there any others which you could enumerate?. -Well, there have been earthquakes, of course. We had a very curious occurrence in the Atlantic. It was found that three Atlantic cables broke within a few miles of each other at one moment, and in a depth, I think, of 1,700 fathoms, or something like that. It could not have been an anchor, it must have been some commotion, either a land slip or an earthquake, or something.

669. What is your judgment as regards this Pacific route; do you think that would be specially liable to such causes of interruptions? Well, I think there are Bome well-known volcanic tracts in the Pacific, and it would be well to go away from them as much as possible; but as far as I recollect, without the book, it is mostly in the north-westerly part, near Japan.

670. When you get south of Fanning Island most of the landing-stages would be, I suppose, on islands of coral formation ?—Yes.

671. Does that make them dangerous as landing-stations ?-Well, in a way. Certainly, you would have to be very cautious, and we would certainly, near those landing-stages, first take soundings and generally investigate the nature of the ground before we laid the cable, so as to guard especially against the cable hanging over precipices, and that sort of thing. But do not think that those obstacles are insuperable. I mean it wants caution.

If you lay plenty of slack in those localities so that you are pretty sure that your cable is not hanging, and take a good set of soundings, which you can do at the time- mean there is no necessity to send out an expedition first-then I think there is no particular danger, but it is certainly a formation which demands a good deal of caution.

672. You said yesterday, in answer to Mr. Murray, that in your opinion if a cable were repaired every year and a certain portion renewed as you found out faults in the cable, that the life of the cable is practically perpetual ?—Yes.

673. Now what influence on the life of a cable does a great depth, such as 3,000 fathoms, have; is it favourable to its life or unfavour- able? It is rather favourable, because it appears that the gutta-percha under pressure of sea water improves in insulation, and it certainly is not at all permeable by water, and in the great depth there is not much current, and therefore it is as favourable to the cable as you could possibly desire.

Mr. Murray.

674. Does what you say about the quality of the cable improving apply to the external cover- ings as well as the insulation and the core?- Oh, no.

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