January 12, 1899J 



NA TURE 



249 



that to which it was apphed by Mr. Preece between 

 Oban and Mull in 1895. I>ut, except in rare instances, it 

 is only likely to replace submarine cables between moored 

 vessels and the shore,(\ir. between light-ships and the coast- 

 guard stations. The point of failure in submarine-cable 

 communication thus happens to coincide with the point 

 of favour of space-telegraphy. The present object of 

 those working at space-telegraphy should therefore be to 

 supplement the cable-system of coast telegraphs, so that 

 all the light-vessels ancl lighthouses of our coasts may be 

 brought into communication with one another and with 

 the life-boat stations. 



Some idea of the scope of the work of completing our 

 coast-telegraphs may be gathered from the fact ' that the 

 whole number of distinctive lights, including port, harbour, 

 and pier lights, light-vessels, and lighthouses on the coasts 

 of the United Kingdom in October 1898 was 1095, and at 

 the beginning of that year only- 51 light-vessels and 

 light-ships were in communication with the telegraphic 

 system. Three additional lighthouses, i.e. those at 

 Godrevy, the Skerries, and Walney Island, were con- 

 nected to the shore during last summer ; but pending ^ 

 further results of the experiments with the system of 

 " wireless-telegraphy," it was thought better to postpone 

 the work of connecting more light-ships to the shore by 

 electric cables. These lighthouses and other sea-marks 

 are maintained out of the fund ■* derived from lighthouse 

 tolls, which amount to over 500,000/., the lighthouses, &c., 

 being thus self-supporting. This fund has lately been 

 augmented by a special grant ; with a view to increasing 

 the efficiency of the system. 



The hard task of establishing communication with a 

 light-ship moored in a tide-way, successively rising and 

 falling at each tide, swinging, rolling, and pitching, and 

 in other ways gesticulating around her uncertain anchor- 

 age, has taxed the resources of cable engineers for the last 

 quarter of a century. The system now generally adopted 

 consists in the use of a swivel' or toggle having a hollow 

 spindle so as to allow a telegraph-cable to be passed up 

 through the middle of it. This swivel is placed between 

 the ship and her moorings at about the water-line. One or 

 more chains lead down from "eyes" on the swivel to the 

 mooring anchors ; there are generally two such chains, 

 or there may be three, spread out tripod-fashion, to 

 terminate in mushroom anchors. A riding-chain leads 

 upwards from the swivel, and is secured to the vessel in 

 the ordinary manner after passing through the hawse- 

 pipe ; the cable is hauled on board through the hollow 

 swivel, over a sheave and on to a drum, which can be 

 turned round by hand as required, to take the twists 

 or "turns" out of the cable as they are formed. A spe- 

 cial veering-drum has been designed by Mr. Benest,'' 

 by means of which this operation of taking out 

 "turns" is performed automatically by a special 

 gear on the drum. Electrical communication is main- 

 tained through the axes of the drum by brush- 

 contacts or otherwise. In rough weather the riding- 

 chain is generally veered out, sometimes up to fifty or 

 sixty fathoms ; and after a gale it is often found in 

 tangled masses, which are sometimes as large in girth 

 as that of a man. The cable itself, if it has not been 

 entangled, has meanwhile been saved from kinking by 

 the swivel device, but it suffers a good deal from the 

 threshing and flattening against the bottom, from friction 

 at the swivel, and occasionally from fouling the chains. 

 An ingenious type (jf veering-cable has been de- 

 signed by Mr. F. C. Crawford,' which is built up 

 in such a way that it is very difficult to make a kink 

 in it. To secure this result, the stranded conductor 



1 Liverpool Mercury, October 26, 1898. 

 - Report of the Royal Commission, September 1897. 

 3 Times House of Commons Report, July i, 1898. 

 •1 Imfcrial Institute Journal, March 1896. 



5 See Bedwell's Patent, No. 367, 1876. 



6 Patent, No. 19,6(6, 1S95. " Patent, No. 21,657, 1895. 



NO. 1524, VOL. 59] 



of seven-tinned copper wires is covered with india-rubber 

 and lapped with cotton tape to make a bedding for 

 the sheathing wires. The sheathing consists of twelve 

 double-tinned steel wires, each coated separately with 

 india-rubber and tape. Finally there is an outer serving 

 of india-rubber, which encloses everything into a compact 

 form, and, while allowing the requisite amount of flexi- 

 bility,' prevents the sheathing wires from slipping over 

 one another when the cable is bent. As a further pro- 

 tection, especially against the "threshing" action, this 

 veering-cable is occasionally threaded with beads or 

 ferrules of lignum vitte, or with washers of india-rubber. 

 Another metallic-circuit method has been tried at 

 Sandy Hook,'- in which use is made of the mooring 

 chains themselves as a means of connecting a telephone 

 in circuit from the vessel to the cable. This method is 

 reported upon very favourably by its designers, Messrs. 

 Blake and Caldwell, but in their account of it the con- 

 ditions are not very fully elaborated. The present writer 

 made some experiments in this direction some years ago, 

 and came to the conclusion that the conductivity of such 

 chains was too variable to be trusted. His tests showed 

 that a mooring-chain of 2-inch links and i-inch iron, 

 12 fathoms in length, after being pickled in tar, dried, 

 and slung up in the air, had a resistance of 9 megohms 

 when tested with 100 volts ; when tested with 750 volts 

 the resistance broke down to 400 ohms. A similar 

 chain, dry and somewhat rusty, had a resistance of 850 

 meghoms. When dipped in water and again slung up, 

 the resistance of the 12 fathoms was 25,000 ohms. 

 Chains sagging in water vvere able to transmit telephone 

 currents with a battery of a few volts. Two mooring- 

 chains, of the same dimensions as those described above, 

 were carefully tarred, and the contacts at the links were 

 cleaned bright over a small area. The chains were then 

 paid out from the shore parallel to one another, 8 feet 

 apart, in about 2 fathoms of water in the Thames, the 

 distant ends being hauled on to a barge. Telephoning 

 between the barge and the shore was impossible, even 

 with 100 volts in the circuit. -AH the electricity passed 

 from chain to chain by way of the water. Brass chains 

 had, of course, much lower resistance than the iron 

 chains ; the resistance of brass chains was practically 

 the same, wet or dry. But it was always found that with 

 any chain whatever in the circuit, the loose contacts 

 caused "buzzing"^ in the telephone. It is possible that 

 .Messrs. Blake and Caldwell used chains under great 

 stress, or that they used some special device, but in view 

 of his own experiments the present writer does not 

 regard the chain system as a practicable one. 



Some years ago an alternative method of connecting 

 a light-ship to a telegraph cable was suggested by Mr. 

 James Wimshurst. He arranged a swivel which con- 

 tained two flat coils, a primary and a secondary, placed 

 one over the other, so that one could rotate coaxially 

 upon the other, for the purpose of avoiding kinks as the 

 ship swings about. As a matter of fact, the danger does 

 not depend so much upon the twist, as upon the thresh- 

 ing action due to the rise and fall of the cable. Mr. 

 Wimshurst's suggestion is worthy of a trial, but it must 

 be remembered that the swivel, in the form proposed by 

 its designer, meets only a very small part of the difficulty. 

 This short review of metallic-circuit and allied direct- 

 cable methods, serves to show that the attempts made in 

 this regard by the Royal Commission have only resulted 

 in partial success.'' While admitting that the problem is 

 now fair game for the space-telegraphers, the present 



1 This cable is in use at Formby l.ight-ship, with very satisfactory results. 

 - Annual Report of the Lighthouse Board of the United States, June 30, 



See Electrical Review, vol. 



. p. 57 and p. 656, 



i Standard, Friday, February i, 1895: "The Ramsgate life-boat and 

 tug Bradford proceeded to the Goodwins, in response to signals of distress 

 from the lightship ; the lightship telephone having, it is understood, got 



