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PUBLIC RECORD OFFICE
Reference :-
C.O. 885
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ALLY WITHOUT PERMISSION OF THE BE REPRODUCED PHOTOGRAPHIC- COPYRIGHT PHOTOGRAPH-NOT TO
PUBLIC RECORD OFFICE, LONDON
18 November 1896.]
Chairman-continued.
Mr. LUCAS.
tropienl sea, and I should say that it is a very advantageous place for a cable, but it is abso- lutely necessary not to lay the cable over shallow patches or over deep holes. We know that there are several deep holes of 5,000 fathoms, and there are a good many patches under 100 fathoms.
you
808. What is the deepest hole that know of on the route from Vancouver to Fanning Island-The deepest soundings are 3,000 and 3,100 fathoms.
809. Are they on the route-They are a little off the straight line.
810. What is the greatest depth that you personally expect to find on that route-If it were sounded closely--
811. With your present knowledge; what is the greatest depth that you have any knowledge of according to present soundings-That is a matter of referring to the chart; I think it is 3,000 odd; I do not remember exactly the soundings.
812-13. You are not aware: I am speaking of the route from Vancouver to Fanning Island: you are not aware of any hole of over, say, 3,500 fathoms that has been found along that route?—Oh, no, certainly not, but that route has not been sounded excepting across from San Francisco to Honolulu.
814. Now, how far do those cross soundings give you a practical knowledge of the route ?-- Well, they are very important. That part of the ocean would naturally appear to be very much freer from islands and coral formations than it is further south, but these cross soundings, which were taken by the Americans, if you refer to them on the chart you will see that if one sounding less had been taken, you would have come to the conclusion that the bottom was all quite even: I mean comparatively even and that it varied between 2,500 and a little over 3,000 fathoms, and you would have said, "This is a beautiful place to lay a cable, and you can go about it; there is nothing to prevent you at all." But there was one more sounding taken in the middle, which was 300 fathoms. [ am only speaking from memory; I have not the chart before me; I think it is 385; that one sounding at once throws doubt upon the whole thing, You know quite well that if you lay a cable across such a place as disaster and accident, the cable would break. If it did not break while laying, it certainly would break afterwards. Cables used to be laid without any soundings at all, and sometimes they were fortunate. Certainly the Atlantic is much freer from islands and shoals than the Pacific; but when you look at the chart and see the number of banks that are named after cable ships, you see the difficulty that has occurred. You will find the "Seine "bank in deep water. Nothing was known of this shoal until the Lisbon- Madeira cable was laid over it. The cable broke soon after the ship had passed the bank, a greater length of it being suspended than could support its own length. Then there is the "Dacia" bank in the same neighbourhood, which was a similar formation found by laying a cable over it. The Faraday Hille in the Atlantic
that there would be
Chairman-continued.
[Continued.
were the same. There was no suspicion of that ridge when the first cables were laid, and it apparently extends right down to the Azores.
815. Then I understand from what you have said that you consider that a preliminary survey is essential before any attempt can be made to lay a cable?—I go further than that. I think that before a cable is laid the place should be carefully and closely surveyed. It seems to me that there is no ocean in which this is more important than the Pacific. I believe there is no ocean in which a cable will last better, and be more safe when it is laid, than the Pacific, but it depends first of all upon finding out where these shallow patches are, and you must also find out the very deep holes, and avoid both those dangers.
816. Are you aware of the Siemens process which claims to make such a survey as is necessary, as the work of laying the cable proceeds, by means of paying out a wire?—Yes, I am quite aware of that. The paying out of a wire will tell you your distance, but it will not tell you your depth. You would go over one of these patches just the same whether you paid out a wire or not. That would not save you
from it
Supposing you were going along, say, in 2,000 or 3,000 fathoms, and you came to a place with 380 fathoms, this wire will measure your distance, but you will go over that place just the sune.
817. But according to the evidence we have received this invention has been brought to such a point that a diagram is drawn of the contour of the bottom, which is shown by subsequent soundings to correspond very closely with the actual facts Such a diagram as that would show a patch of the nature you describe?—Take the case where the Seine " went over a patch. Before you had time to draw any diagram or anything else the cable was broken; the wire will tell you how fast you are going and how far
but as to telling gone; sibly do that, as the wire will not touch the you the depth of the water, it cannot pos-
you
have
bottom for many miles astern of the ship when she is paying out the cable, and it could tell nothing whatever about the shallow patch which might be underneath the ship.
818. Have you ever seen this process in opera- tion?-No.
-
819. Now, as regards the span from, we will say, Vancouver to Fanning Island, how much sluck would you think it sufficient to allow ?— From Vancouver to Fanning Island I should expect to pay out in that depth of water, on a cable like that, from 10 to 12 per cent. of slack, but I should certainly provide 20 per cent. of slack before starting. You must have something in hand. And besides, when you lay a cable across deep water, you require to have some apare cable left for possible repairs after- wards, especially if you are going as far as the other side of the world with your cable; you would not think it advisable to go with just the net quantity that is required, and 1 think from past practice that all deep-sea cables up to now have been provided, when the expedition starts,
18 November 1896.]
Mr. LUCAS.
Chairman continued. with something like 20 per cent. of slack, know- ing that there will be some left at the end.
820. Have you seen this letter from Sir George Henry Richards to Mr. Mercer of the 8th July (producing letter); do you know it ?—Yes.
821. Will you take upon yourself to hand this letter to the Committee officially-It written to the Committee, was it not?
822. It was written to Mr. Mercer for the purposes of the Committee?-Yes (letter put in)."
was
823. I see that on this point Sir George writes "We have calculated the distance from Van- "couver to Fanning us 3,316 nautical miles"? -Yes.
824. And have allowed 10 per cent. as the "probable amount of slack that would be paid "out, making the total length of this section "3,650 nautical miles "?-May I interrupt you a moment. His reason for saying 10 per cent. was not in the least meaning that 10 per cent. should be provided, but calculating the speed of the cable length is such a very important element, and he has wished to take the most favourable view of the case, and has therefore taken 10 per cent. and added that to the dis- tance, to arrive at the probable length of cable through which you have got to calculate your speed.
825.The principal question to decide," he writes further on, is the weight of copper and "gutta-percha that should be used in the core," and he proceeds to give a table of the composi tion of the core of some of the principal cables existing, and finally he recommends a core for this
purpose of 650 lbs. copper and 400 lbs, gutta- percha?--Yes.
*26. Which would, when laid in a length of 3,650 miles, have a K.R.-94, which, estimated "on the basis of the working of existing cables, "would allow of the transmission of 70 letters per "minute"?—Yes.
827. Seventy letters, how many words would that be?-1 think he points out to you after- wards that the question of words a minute is always rather misleading. The question of words a minute is generally spoken of as five letters to a wird. suppose that that came out of the old times when codes did not exist at all and when all messages were sent in open, and possibly in those days they did not even skele- tonise messages as they do now; they did not leave out the "ifs" and "ands" and "ofs" and only send the long words. Quite possibly five letters a word was right at that time, but at the present it is extremely misleading. reputed word, and in nearly all cases in which I have seen speed spoken of in "words a minute," it is always expressed in these reputed
words.
It is a
828. Then do I understand that you adopt Sir George Henry Richards's statement, which is to this effect: "Moreover, the speed which is usually "spoken of in connection with telegraph lines is misleading, it being calculated from the attain "able speed with press work, counting five letters "as a word, whereas the actual speed of paying "words in code traffic does not amount to more "than about half this"?-YER.
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829. Do you consider 70 letters per minute to
Chairman--continued.
be enough for a cable of this importance?- Seventy letters per minute would give you on the section from Vancouver to Fanning Island some thing like four or five paying words a minute, not
more.
830. Have you ever laid a cable which gave no more speed than that?No; the slowest cable, I think, was the 1869 French Atlantic from Brest to St. Pierre. That cable was a very slow cable. It was laid across the Atlantic when there were not very many soundings, and It was laid across a very large rocky patch in the centre, which is 1 continuation of the Azores and the other hills, and it failed there after some years, and had to be repaired, when a considerable length of cable was in- serted. This so increased the length that its speed became slower than ever. And then there were other repairs, and as each repair added to its length, in its last years it became so slow that it was quite a question whether it was worth the expense of maintaining it for the small traffic that it carried. I think that was the worst instance of a slow cable.
831. But a cable to carry, say, 15 or 18 words per minute? What kind of words? reputed words of five letters?
832. Reputed words per minute of course would cost a great deal more than the 12 reputed words a minute which was asked for by the Dominion Government in their tenders 7-Yes.
833. What I wanted to ask you was this, do you say that a cable of the kind specified for is, quite irrespective of speed, as heavy a cable as you recommend being laid on such a route as this? Yes, I should not recommend a heavier core than that.
834. Quite irrespective of the speed attain- able?—I should not recommend a heavier core Six hundred and than that, for this reason. fifty pounds of copper loads a cable, it is a very heavy weight to carry in a cable when you have to pick up; certainly you could lay a cable with a much heavier core; but when you have to pick it up you find that you get such a strain that there is a distinct limit as to what the very best steel wire will bear.
635. And you have estimated for the extreme tension that you think such a cable would bear? --- Yes.
Iu
836. That is to say, a breaking strain of eight and a-half tons ?—You may have a bigger break- ing strain if you have a greater weight of wire the ue is proportionate to the other, But the difficulty is this, that you must not go beyond a certain limit of strength in your steel wire. If you go beyond that you will
get such rigidity in your wire, such a loss of elasti- city, that it would be no advantage to you. picking up a cable there is a rise and fall in the ship. Now, if the cable was not elastic, and you had, each time the ship gave a lift, to lift the cable from the very bottom of the ocean, perhaps three or four miles of cable had to be lifted, there is no material on earth could stand it. As a matter of fact, I am confident that the elasticity of the cable is the saving of it. The rise and fall of the ship is all taken up by the elasticity of the first half mile or so of the cable.
H 4
• See page 268.
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