402 Mr. Brett, on the Submarine Telegraph. [March 20, 



cannon ball, while it continued to descend, would drag it out at 

 a decreasing rate. 



A contrivance was also made by which the ball would detach 

 itself, quills being inserted at the end which passed through the 

 hollow of the ball. .Specimens of the bottom were thus brought up 

 by the quills, on the ball striking the bottom, which proved to con- 

 sist of the most minute microscopic shells. 



The greatest depths which have been reached by these means 

 in the North Atlantic Ocean have been 25,000 feet. 



It was some two years since, when Mr. Fafaday was explaining 

 the subject of induction, that a fact was named to him of a current 

 being obtained from a length of 300 miles of gutta-percha covered 

 wire half an h6ur after contact with the battery. I remember 

 speaking to him on the subject, and enquiring if he did not believe 

 this difficulty was to be overcome, and I received from him every 

 encouragement to hope it might ; but it at once became necessary 

 that this point should be cleared up, or it would be folly to pursue 

 the subject of the union of America with this country by electricity. 

 I at once earnestly urged on Mr. Whitehouse to take up this sub- 

 ject, and pursue it independently of every other experiment, and a 

 successful result was at last arrived at on 1000 miles and upwards 

 of a continuous line in the submarine wires in the several cables, 

 when lying in the docks. It did not rest upon one but many 

 thousand experiments ; it was further proved on 2000 miles of sub- 

 terranean wire in the presence of Professor Morse, while in this 

 country, and beats from 230 to 270 per minute were recorded, or 

 equal to twelve to fifteen words per minute. 



In the Atlantic cable the copper or conducting wire is com- 

 posed of seven twisted wires formed into one, thus avoiding the 

 danger of a flaw, which any single wire might be subject to ; 

 three separate coats of gutta-percha are then laid one over the 

 other, the wire being thus perfectly insulated. This gutta-percha 

 core passes and repasses in the course of its manufacture no less 

 a length than 40,000 miles. The outer iron wires, of which there 

 are 1 26 to each mile, are twisted into strands each containing seven 

 wires, making an aggregate of 315,000 miles to the 2500 miles of 

 cable. The construction of the cable is under the control of Messrs. 

 Bright and Whitehouse. 



The ultimate union of America with Europe by electricity may 

 now be considered a certainty. Providence has placed this object 

 within our reach ; there are no practical impossibilities in the way 

 of its accomplishment ; and those united with us in the undertaking 

 do not regard the means required in comparison to the good to be 

 accomplished. 



[J. W. B.] 



