360 ADDENDA. 



The Atlantic Telegraphic Company, availing itself of this princi- 

 ple, have, instead of attempting to span the ocean with a wire ca- 

 ble, which would require several ships to transport, wisely decided 

 to use a single conducting thread of copper, or a fascicle of them, 

 coated to insulation with gutta percha, and properly protected. 

 Instead of being, like the lost French cables of the Mediterranean, 

 as large as a man's arm, this for the Atlantic will probably not be 

 larger than his finger, and one vessel can carry enough to reach 

 across and lay it out. 



I speak with caution, and with a due sense of the responsibility 

 I incur, but I think the researches and discoveries in this field 

 warrant me in saying that there is no limit but the electrical one 

 to the length of wires of submarine telegraph that may be estab- 

 lished ; that, in deep water, telegraphic wires may be laid across 

 the Indian and Pacific Oceans as well as across the Atlantic and 

 [Mediterranean ; that they may be laid in any direction ; that the 

 expense of laying a tliousand. miles of telegraphic wire — for we 

 should call it cable no longer — in the deep sea need not exceed the 

 expense of stretching a wire of equal length over the land ; and 

 furthermore, that there is this difference in favor of the subma- 

 rine telegraph : once at the bottom of the deep sea, there will be no 

 wear and tear as for the renewal of posts, wires, and the like on the 

 land, and no interruption of communication by storm and accident. 

 In shallow water and " on soundings" there will be such liability. 

 I speak alone of the deep sea, and upon the assumption that the 

 durability of gutta percha is lasting, and its insulating powers 

 proof against the hydrostatic pressure of the ocean. 



Professor Morse has passed telegraphic signals through an un- 

 broken wire " upward of 2000 miles in length" at the rate of 270 

 per minute. This was passed through gutta percha coated wires 

 under ground. How far can they be passed through submarine 

 wires ? The answer to this question, and not the depth of the sea, 

 will express and fix the limit of maximum length to lines of sub- 

 marine telegraph. 



December, 1856. 



THE END, 



