720 



TELEGRAPH, ELECTRIC. 



In the second attempt, begun in raid-ocean, 

 June 26, 1858, after the cable had several times 

 parted and been re-spliced, but still without 

 success, the enterprise was for the time aban- 

 doned. In the third expedition, the paying-out 

 being also commenced in mid-ocean, and on the 

 27th of the succeeding July, a cable was suc- 

 cessfully laid, its western end being landed on 

 the 5th of August; but the transmission of 

 signals by this, at best irregular, finally ceased 

 about the 1st of September of the same year. 

 A fourth expedition, and in which the steam- 

 ship Great Eastern was for the first time em- 

 ployed, set out from Valentia Bay in July, 

 1865, laying the shore end of a cable of new 

 and improved construction at.that point on the 

 21st of the month named: after the paying-out 

 .of about 1,212 nautical miles' length of this, a 

 fault became evident, and, the cable parting 

 during the efforts made to recover the defective 

 portion, and grappling for it proving unsuccess- 

 ful, this attempt also was abandoned. It has 

 been estimated that these (thus far) unavailing 

 trials had already involved an outlay of not less 

 than $6,000,000. 



The electricians in charge, at Valentia, of 

 the shore end of the cable of 1865 continued 

 to test daily, at the hours of 12 M. and 6 

 p. M., the conductivity of the core, this con- 

 dition, being determined in a case of the kind 

 by comparison of the amount of resistance op- 

 posed by the wires to the passage of the cur- 

 rent, as shown by the needle of a galvanometer 

 placed in the circuit, with the accurately known 

 f number of " units " of resistance of another 

 coil of given length, and charged in succession 

 from the same battery. The general result 

 being that the average resistance proper to tho 

 core at the moment of the rupture, although sub- 

 ject to marked fluctuations through the dis- 

 turbing agency of magnetic storms, and even 

 (it appeared) through that of changes of atmos- 

 pheric pressure a high barometer being at- 

 tended with increased resistance, and . v. 

 was still at other times steadily maintained, 

 ranging in fact very close to 5,000,000,000 

 "units" of the standard employed, it followed 

 that no fault or leakage of the current had 

 supervened at any point nearer than the broken 

 extremity; or, in other words, that the insula- 

 tion and continuity, and hence the working 

 condition, of the cable remained unimpaired. 

 Prof. William Thomson, among others, main- 

 tained accordingly that the broken cable could 

 still be completed to a perfect line; and under 

 this assurance and the yet untiring efforts of 

 Mr. Cyras W. Field and others, in behalf of the 

 general enterprise, it was determined to under- 

 take in 1866 both the laying of a new cable, 

 and the recovery and completion of the large 

 portion remaining submerged from the previous 

 year. 



The newly-formed " Telegraph Construction 

 Co.," composed substantially of the manufac- 

 turers, undertook* to produce the additional 

 amount of cable to make the 2,700 miles re- 



quired for both the purposes just named, and 

 at the mere estimated cost, 500,000 ; but on 

 condition of receiving the further sum of 100,- 

 000 in case of the success of the enterprise. 

 The sums so required were to be raised by the 

 " Anglo-American Co.," which appears mean- 

 time to have taken the place of the " Atlantic 

 Tel. Co. ; " and the profits of the line, when 

 realized, were to be divided in certain stipulated 

 proportions between the shareholders in the 

 new and those in the former companies. 



The cable required in addition to the some- 

 what more than 1,000 miles in length remain- 

 ing from that of 1865, was completed early in 

 May, 1866. The sailing qualities of the Great 

 Eastern and her capability of being readily 

 manoeuvred, had been greatly improved by 

 the clearing from the bottom of the ship of the 

 thick coating of muscles and other marine 

 growths, and by arranging the paddle-wheels 

 so that either could be cast loose, the other, 

 and aided by the screw, alone rotating. Tho 

 three tanks of the great steamer admitting only 

 2,200 miles of cable, the screw-steamer Med- 

 way was chartered to receive the remaining 

 600 miles (part of the old cable) ; while the 

 screw-steamer Albany and the government 

 war steamer Terrible, completed the cable 

 fleet. 



The new cable was, in the main, similar to 

 that of the year before; but the iron wire used 

 in it had been galvanized, the better to resist 

 rusting, and also in part annealed ; and tho 

 construction was such as to throw upon the 

 Manila yarn its proportion of the total strain. 

 The cable was thus at once more pliable and 

 stronger ; and the yarn in it not being saturated 

 with the tar solution before used, it was less 

 liable to slip, when, in paying out, it might be- 

 come necessary to check it with the rope- 

 stoppers. The picking-up machinery in the 

 bow of the Great Eastern was of great dimen- 

 sions and strength ; and this and the paying- 

 out machine (also stronger than before, and 

 which could now be made also to haul in,) 

 were each connected with a 40-horse-povver 

 engine, independent of those propelling tho 

 vessel. 



Cut showing a section and an exterior view 

 of each cable drawn to the full size, so that com- 

 parisons may be readily made. 



1858. 



The cable of 1858 had for a conductor a cop- 

 per strand of 7. wires, 6 laid around 1 ; weighv 

 107 Ibs. per nautical mile. The insulator was 

 of gutta-percha, laid on in three coverings; 

 weight 261 Ibs. per nautical mile. The outer 

 coat was composed of 18 strands of charconl 



