OCEAN-CABLES. 39 



gether with other evidence." Attention is called in the report to the 

 " remarkable fact that in almost all cases small cables had been found 

 liable to mishaps, while the heavier the cable had been the greater 

 had been its durability." The report is full and complete, and estab- 

 lishes principles which up to the present time have uniformly guar- 

 anteed success, while the neglect of them has as uniformly resulted in 

 partial loss or failure. 



The loss of cables was found to be attributable to the following- 

 causes : First, and the most important of all, from imperfect manufac- 

 ture, resulting without doubt, prior to this date, from inexperience of 

 the materials for insulating the copper wire, and from ignorance of 

 the fact discovered by Prof. Thomson about 1856, viz., that some kinds 

 of copper wire were no better than iron for the purpose of conduc- 

 tivity, and that it required carefully-selected copper to give the desired 

 standard, which may be represented by a copper wire one-tenth of an 

 inch in diameter, being equal to an iron wire one-third of an inch in 

 diameter for electrical purposes. All cables manufactured previous to 

 this date had no advantage from this discovery. 



There appear to have been mechanical difficulties in keeping the 

 copper conductor in the centre of the insulating medium, so that the 

 copper was sometimes found to be almost visible under the light film 

 of gutta-percha which covered it. The electric current soon weakened 

 this film, stronger currents were used to overcome the weakness of 

 the signals, and the cable was soon destroyed. Experience about this 

 time had established that a cable from the commencement of its manu- 

 facture to the time of its being laid should be tested under water and 

 under pressure, and kept as much as possible under all the conditions 

 in which it was meant to contimie. 



Attempts to lay cables from sailing-ships towed by steamers was 

 another source of failure. The ships had not enough steerage-way 

 when met with strong head-winds, and too much slack was paid out. 

 It was difficult under such circumstances to steer a straight course, 

 and sailing-ships possessed no power of being readily stopped when a 

 fault or accident occurred. 



Many accidents happened from inexperience in the method of pay- 

 ing out cables ; at the present day the wonder is, that they should 

 have succeeded so well with the rude methods and inexperience which 

 then existed, and not that there should have been many failures and 

 much recrimination. Reading the history of these first attempts to 

 place a net-work of cables at the bottom of the ocean fifteen and twenty 

 years ago, is a good deal like reading the old stories of the early voy- 

 ages of discovery. There are difficulties and disasters peculiar to 

 every attempt, and the grand result is that, one way or another, they 

 were overcome, or else they suggested such modifications that their 

 recurrence was avoided, and an accident to a well-manufactured cable 

 no longer constitutes a loss. 



