NATURAL PHILOSOPHY. 105 



several lines are twisted and plaited about each other, in spiral convo- 

 lutions, in the manner of an ordinary cable or rope. The next super- 

 incumbent coil to this consisted of hempen yarn, previously saturated 

 in a reservoir of prepared pitch and tallow, and, in its turn, is tightly 

 twisted and compressed, impernieably and by steam-power, over the 

 gutta percha, with its enclosed copper wires. This is overlaid again 

 with a series of hempen yarns, five or six in number, and about an 

 inch in diameter, saturated in the pitch and tallow, with a view of 

 what the workmen call "Avorming" the gutta percha. The gutta 

 percha thus protects the wire, and the hempen yarn in addition acts as 

 a cernentitious material to the gutta percha, which, ultimately, has 

 thrown over it a coat of galvanized wire. This completes the first pro- 

 cess, and the manufacture of the rope in the spiral form is for the 

 purpose of giving flexibility. The second process consists in hauling 

 off the cable, so far completed, and passing it on to another wire-rope 

 machine, where the cord is completely covered over with ten galvanized 

 iron wires, each wire being about the thickness of a lead-pencil, and 

 known as " No. 1 galvanized wire gauge." This galvanized iron sheath- 

 ing is to protect and preserve the interior layers from the action of the 

 sea, and the weight is considered to be sufficient to sink the cable ex neces- 

 sitate gravilatis. The appearance of the cable, thus completely encased 

 in a shining coat of galvanized iron, and divested of tar and dirt, is 

 quite lustrous and silvery. The entire weight of the cable thus 

 completed was about 200 tons. The actual submersion of the great cable 

 took place on the 25th of October. The huge coils were arranged on 

 board her majesty's ship Blazer, towed by the steamship Fearless. One 

 end of the cable being secured to the beach, on the South Foreland 

 coast, the Fearless then steamed ahead having made fast her towing 

 tackle to the hull of the Blazer at the rate of two miles an hour out 

 to sea, the men on board the latter vessel paying out continuously the 

 cable over her stern, from whence, by the action of its own weight, it 

 sank into the submarine sand and valley. The track between South 

 Foreland and Sandgate the corresponding point on the French coast, 

 and which was selected as presenting, from soundings and surveys, 

 the fewest obstacles and probable disturbances was marked out by 

 pilot buoys as the best site for the submerging of the wire that could 

 be adopted by those having the best knowledge of naval and marine 

 dynamics. The depth of the sea line at starting point was from 20 to 

 30 feet, and its maximum depth 180 feet, or 30 fathoms. At inter- 

 vals during the progress, fusees were fired, and messages sent along the 

 wires, in order to test the perfectness of the connection and insulation. 

 The distance from coast to coast was 21 miles, and the length of wire 

 provided for, 24 miles ; yet, notwithstanding the surplus wire, the line 

 was found, on nearing the French coast, to be wanting in length for a 

 distance of more than a mile. This mishap of the cable running short 

 arose from the fact that, while the Blazer was being towed by the 

 Fearless at only two miles an hour, the cable, at certain intervals, was 

 run out at the rate of four and five miles an horn-, which necessarily 

 caused it, from want of regularity in the delivery motion, to take the 



