NATURAL PHILOSOPHY. 



115 



where the process is purely mechanical, no such inconvenience can occur, and 

 all errors of manipulation are easily avoided. The method employed by M. 

 Bonelli, is to write the despatch, or draw the sketch to be transmitted, on a 

 metalizcd or conducting paper in non-conducting ink. It is then placed on 

 the transmitting machine, and passed by clock-work under a number of fine 

 conducting wires, arranged in line like the teeth of a comb. These conduct- 

 ing wires (there are sixty in Bonelli 's machine) are insulated separately in a 

 gutta-percha cable, which is stretched between the two places in communica- 

 tion. At the other end, they are spread out in the same comb form. Under 

 this receiving comb is passed, by means of similar clock-work, a chemically 

 prepared paper, the yellow color of which is changed to green by the action 

 of the magnetic currents which pass over the wires. When the wires at the 

 transmitting end are passing over the insulating ink, they of course convey 

 no fluid, and make no change in the color of the receiving paper. The mes- 

 sage appears, therefore, in yellow letters on a green ground, the letters being 

 composed of lines, the nearness of which depends on the distance between 

 the wires. To accomplish the same thing with one wire, it is necessary to 

 have the two machines move in exact time with each other, and the point of 

 the wire must pass necessarily over every portion of the written despatch, 

 transmitting it point by point. By Bonelli's method, this exactness of time 

 would not be requisite. 



THE ATLANTIC CABLE. 



The great scientific event of the year 1858 was the successful submergence 

 of the Atlantic Telegraph Cable, and the temporary transmission of messages 

 between the Old World and the New. The main facts pertaining to the his- 

 tory of this important enterprise are as follows : 



The telegraphic fleet, comprising the Niagara and the Agamemnon carry- 

 ing the cable, with two attendant steam-frigates, sailed from Queenstown, 

 Ireland, on the 17th of July, 1858, and united at the rendezvous, lat. 52 5' 

 long. 32 40' W., on the 28th. On the succeeding day, July 29th, at 1 p. M., 

 lat. 52 59', long. 32 27 / W. the "splice" between the two ends of the cable 

 was successfully made, and electrical signals passed perfectly through the 

 whole length on board both ships. Depth of water 1550 fathoms. The dis- 

 tance from the entrance of Valentia harbor was eight hundred and thirteen 

 nautical miles; to the entrance of Trinity Bay. N. F., eight hundred and 

 twenty -two nautical miles, and from there sixty miles to the telegraph house 

 at the head of the Bay of Bulls, equal in all to eight hundred and eighty -two 

 nautical miles. The Niagara had sixty-nine miles farther to run than the 

 Agamemnon. Each ship had on board about eleven hundred nautical miles 

 of cable. The following table presents a condensed view of the Niagara's 

 voyage : 



