I 1 8 THE SCIENTIFIC PAPERS OF 



decide with such accuracy as in the Atlantic whether the cable 

 was taken hold of by the grapnel or not. The reason no doubt 

 was that the Mediterranean had a rocky bottom, full of coral 

 formations in moderate depths, and rocky even at its greatest 

 depths ; whereas the bottom of the Atlantic appeared to be almost 

 perfectly smooth. Another circumstance highly in favour of the 

 Atlantic cable was that there seemed to be no animal life at the 

 bottom of the ocean ; whereas in the Mediterranean, if such a 

 cable covered partially with hemp were put down to the bottom, 

 it would be utterly destroyed in a few months by animals breeding 

 upon the cable and eating up the hemp, leaving the wires un- 

 protected and a mere burden upon the tender core. This had 

 been the case with the early Candia and Chios cable, and with the 

 Toulon and Algiers cable laid in 1859, both of which had become 

 entirely useless after being down, the former only six months, and 

 the latter only about eight months. On the contrary, the specimen 

 now exhibited of the recovered Atlantic cable of 1805, which had 

 been down at the bottom of the ocean for twelve months, was 

 evidently as perfect as at the time that it was laid, although its 

 construction was the same as that of the Toulon and Algiers 

 cable. On all accounts, therefore, there seemed every reason to 

 hope that the Atlantic cable now laid would prove a durable one. 



MR. C. "VV. SIEMENS further said he had seen the hemp covering 

 of a cable entirely eaten away, and even the gutta-percha indented 

 about 1-1 6th or l-8th inch, but beyond that point the action of 

 the marine animals did not appear to go. With regard, however, 

 to the safety of the cable when deprived of its hemp covering, 

 although it might continue efficient if lying upon a perfectly 

 smooth bottom and with the tensile strain perfectly equalised 

 throughout its length, yet that would certainly not be the case in 

 the Mediterranean, where he was satisfied that as soon as the cable 

 had ever worn weak at any point it would break, because the 

 bottom of the sea was so uneven that the cable hung unsupported 

 in a great many places. He had seen pieces of Mediterranean and 

 Red Sea cables which had evidently given way at points of 

 suspension by the rusting of the iron wires ; and wherever the 

 cable had parted, the core had been elongated several inches, and 

 had shown electrical faults. Wherever the bottom was not 



