THE SUBMARINE TELEGRAPH
BETWEEN ENGLAND AND IRELAND.
In our Journal of last week we described the accomplishment of this most desirable means of communication between England and Ireland by an electric telegraph wire stretched across the Channel from Holyhead to Howth. We now give some additional detail, with illustrations, of the interesting work.
Very little notice of the intentions of the projection of this undertaking was given to the public, the Company prudently awaiting the completion of their project before they gave it publicity. At the same time it was known to some public departments, and a few individuals. The Admiralty had been applied to for a steamer and an officer to assist in laying down the line; the Prospero, lieutenant Aldridge, R.N., had been ordered round to Holyhead from Pembroke; and the Company had requested Captain Beechey, R.N., to assist them by his advice and long experience in the Irish Channel, and to superintend the laying down of the wire in the proper direction.
The rope forming the submarine communication is rather less than an inch in thickness, and contains only a single copper wire for the transmission of the electric fluid: this is enclosed in a double gutta percha tube, and surrounded with twelve galvanised iron wires, which completely protect it from chafing upon the bottom. The length of line actually required was not more than fifty—nine statute miles; but the experience of the Dover and Calais operation had shown that some additional line would be necessary; and, accordingly, eighty miles of it was put on board.
The gutta percha tube had been manufactured by Mr. Samuel Statham, of the Gutta Percha Works, Wharf—road; and the wire by Mr. Newall, of the Iron Wire Manufactory at Gateshead. The weight of the wire when complete was about eighty tons, or a ton per mile.
The whole was embarked on board the Britannia steamer at Whitehaven, and arrived at Holyhead early on the morning of the 29th of May last.
It was the intention to have run the line across the Channel at once, as everything conspired to favour the project: the weather was fine, the tides (of great importance) were weak, the Prospero and the officers had arrived, and nothing seemed wanting; but, on examining the wire, which had been hastily put on board, it was found that part was defective and would require to be cut out, and also that part of the line required to be re-coiled; it was, in fact, determined, before any attempt was made to lay it down, that every part should be thoroughly tested afresh, so that it was Monday evening, the 31st before everything was finally prepared. On that evening the continuity of the wire was tested by passing a shock through the whole of the line and discharging a cartridge of powder. The explosion was instantaneous, the fluid passing through the whole length of the coil of wire as it lay piled up in the hold of the vessel—a distance of 401,280 feet in an instant.
Everything was now ready; but the delay had driven off the time to the approach of the spring tides, which run very strong in the Channel, and it was doubted whether the line could be let out sufficiently fast to allow of the vessel making the passage without a great waste of line; and with such a tide, and so small a rope, it was obvious that, a check from the line getting entangled or other impediment, would have broken the cable and been fatal to the measure for that time at least. Much anxiety was in consequence felt; but, after a consultation with Captain Beechey, it was determined to proceed.
Accordingly, at two o’clock in the morning of the 1st of June the steamers started and anchored for awhile off a small bay close under Holyhead Mountain, whence the submarine line was to be connected with the line on shore; this was soon done, and at four o’clock the steamers commenced their interesting course across the Channel the Prospero, with Captain Beechey and Lieutenant Aldridge on board, leading the way ; and the Britannia following close in her track.
At the end of ten miles it had been determined to compare the distance actually gone over with the length of line that had been run out, and if the quantities were not very disproportionate to continue the route; but, if otherwise, the attempt was to be abandoned until after the springs were past. Accordingly signals were exchanged, and it was with no small degree of delight found that, in this ten miles of distance, only twelve miles of line had been expended. The next comparison was 16 miles distance to 20 miles of line; the next 25 to 31; then 47 to 55. In this manner the comparisons were kept up, the position of the vessel being accurately determined by the measurement of angles between peaks of mountains known to the officers in the Prospero as points which had been determined by the Ordnance survey; the length of line veered out on board the Britannia being registered by a machine attached to the wheel by which it was let out, as shown in the Engraving.
Mode of letting out the wire
|A. Drum by which the wire was let out.
B. Break, to regulate the tension of the wire.
C. Indicator, to show the length of wire run off.
D. The wire.
The day was fine, the country on the Welch coast was still in sight, when the Wicklow hills and the land at the back of Dublin and Howth, rose above the horizon, and at a little after eight o’clock in the evening the vessels reached their points of destination off Howth pier, having accomplished their task in sixteen hours, during which time they had passed through three tides nearly, viz. two floods and one ebb: but so successfully had these streams been evaded, that the length of line veered out was only 65 statute miles to 59½ , the real distance as the crow flies. The average rate of the vessel, therefore, was four statute miles per hour; the greatest depth of water passed over was 84 fathoms,
As the vessels neared Howth, the cheers of the people on the pier welcomed their arrival; and. the completion of the undertaking was confirmed by a cannon on board the Britannia, at Howth, being fired by means of the wire from Holyhead; and to apprise the Admiralty of the success, the following message was telegraphed across the Channel:—
From Messrs. Newall and Co. to the Duke of Northumberland.
The submarine telegraph is completed, with the aid of Capt. Beechey and Lieut Aldridge. Thanks to your Grace.
Thus was accomplished this most ardently wished for communication which was but yesterday, as it were, considered of doubtful practicability And it compels us to remove from our minds much of the doubt we have hitherto entertained as to the possibility of effecting that far greater undertaking, the communication between the continents of Europe and America, which we one day hope to see completed.
From the position of the Britannia off Howth, the wire had to be carried on shore, and connected with the land line from Howth to Dublin for which purpose a thicker wire was used than that across the Channel. When done, and the whole line thought to be complete, and the parties were about to rest from their arduous labours on the following day, it was discovered that the continuity was by some unaccountable means destroyed, and no message could be passed either way between Dublin and Holyhead. The wire to Howth was tested, and found perfect; and on severing the part at the ship, the submarine continuity was also fortunately found perfect; so that the defective portion evidently rested between the ship and the land line, but where, was wholly uncertain; the line between the two places had therefore to be entirely taken up, and examined bit by bit. At last the defective part was discovered, and it appeared to have been occasioned by a spade being driven against the line while burying it in the trench. The labour which this little bit of carelessness, or perhaps ignorance, occasioned, is beyond description. but will be conceived when told that it took a whole day to remedy. All is now happily right, and the telegraph will be open to the public as soon as the necessary arrangements with the various lines in connexion with it can be effected.
The annexed Sketch exhibits the steamers laying out the line when off the lighthouse, of the South Stack, which projects from the foot of Holyhead Mountain.