_Revenue._--The fifteen Atlantic cables now in use represent a total capital of well over £20,000,000 sterling. A knowledge of the profits derived from each system is not readily arrived at; but from a comparison of the traffic receipts or "money returns" of the oldest existing Atlantic company at different periods, we are bound to conclude that the "takings" are, roughly speaking, very much the same now as they were twenty-five years ago. This is explainable by the fact that, although the number of messages now passing is much greater, the reduction of the rate (with the ever-increasing competition of rival lines) just about cancels the advantage, so far as receipts are concerned. Roughly speaking, however, the annual gross traffic on transatlantic telegraphy stands at about £1,200,000, divided among two English companies, two American, one French, and one German company. Both the two latter are materially subsidized by their respective Governments, who now foresee the desirability of being independent of cables under English control. FOOTNOTES: [1] For particulars regarding preelectrical telegraphy and previous researches in electrotelegraphy, the reader is referred to A History of Telegraphy to the year 1837, by J. J. Fahie, M.I.E.E. (E. and F. N. Spon, 1884). [2] A certain knowledge regarding electric and magnetic science has to be assumed here; and, for further particulars on this subject, the reader is referred to another volume of this series, The Story of Electricity, by John Munro. [3] Submarine Telegraphs: Their History, Construction, and Working, by Charles Bright, F.R.S.E., A.M. Inst. C.E., M.I.E.E. (London: Crosby Lockwood & Son, 1898.) [4] B.W.G.--Birmingham Wire Gage. [5] It was gravely suggested by a prominent naval officer to thread the line through old cannonades lying idle, at Portsmouth harbor. This notion was not taken up; but a light chain twined round the insulated conductor throughout its length would certainly have served the purpose better than the leaden weights, inasmuch as it would have protected the line from chafing, besides being less liable to damage the core. [6] Some critics had actually supposed that the method of signaling was that of _pulling_ the wire after the manner of mechanical house-bells; and were at pains to point out that the bottom of the channel was too rough for that. [7] For further particulars, see the Life Story of Sir Charles Tilston Bright. (London: Archibald Constable & Co., 1898.) [8] It will be readily understood that without this weight, the line would not for certain descend to the bottom--and certainly not in a straight line--in any considerable depths. On the other hand, it would be impossible to recover an effective weight without great risk of breaking the line. For this reason the weight is abandoned, and a considerable number may be found at the bottom of the sea in every quarter of the globe.