TALKING BY TELEGRAPH. 57 



tection to such vessels, was a dangerous influence. The Euxine, Oliver 

 Cromwell, Calcutta and Cora were loaded under the tips, at Newcastle, at 

 the same time, with the same coal and from the same seam, sometimes one 

 ship being under the tip and sometimes another. Each carried from 1,500 

 to 2,000 tons of coal. The first three, which were well ventilated, were bound 

 for Aden, and the last, which was not ventilated at all, for Bombay. The 

 Euxine, Calcutta and Oliver Cromwell were all totally destroyed b}^ sponta- 

 neous combustion, while the Cora carried her cargo safely to Bombay. 

 Numerous instances of similar character are reported, and the commission 

 concluded that the pressure recently put upon ship owners and masters to 

 adoj)t systems of thorough ventilation tor coal cargoes increased the risks. 



TALKING BY TELEGRAPH. 



The newly discovered science of telephony has created much interest 

 among scientific men and electricians lately, and is likely to produce a revo- 

 lution tn the commercial world if the wonderful experiments ia talking and 

 singing, now being made between Salem and Boston, prove successful when 

 made under the ordinary conditions of electric telegraphing. The inven- 

 tion is thus described in the Graphic : 



The telephone consists of a powerful, compound, permanent magnet, to 

 the poles of which are attached ordinary coils of insulated wire. In front 

 of the poles, surrounded by the coils of wire, is placed a diaphragm of iron, 

 while a mouth-piece to concentrate the sound upon this diaphragm substan- 

 tially completes the arrangement. When the human voice causes the sen- 

 sitive diaphragm to vibrate, electrical undulations are induced in the coils 

 sui'rounding the magnets in precisely the same manner as the undulations 

 of the air are produced by the voice. These undulations then travel through 

 the wire, and, passing through the coils of an instrument of similar con- 

 struction at a longer or shorter distance, as the case may be, are again 

 transformed into air undulations by the diaphragm of the instrument. It 

 will be borne in mind that the voltaic battery is dispensed with entirely, 

 and all that is needed for transmitting the voice sounds are the instruments 

 and the telegraph wire. In this connection a remarkable peculiarity of the 

 telephone is that a practiced ear is able to distinguish the voices that speak 

 through the instrument. The inventor claims that the electric wave of the 

 telephone can be perfected to render free and easy the sounds generated by 

 the human voice to any length. 



It is well known that the expense and trouble of batteries and keeping 

 them in order has been one of the main items in the account of telegraph- 

 ing, and with the present system expert operators are required. Under the 

 system of telephony the cost of constructing the line and putting in the in- 

 struments is all, and the affair is permanent so long as the wires and poles 

 shall last. 



Eespecting the adaptation of the invention to long distances, the late 

 experiments warrant the belief that it can be made to answer all the pur- 

 poses of the telegraph either under the ocean or across the land. The 

 artificial resistance employed in the experiment between Boston and Salem, 

 as already hinted, was much greater than an equivalent of the length of the 

 wire between New York and San Francisco of the Atlantic cable. In fact, 

 the inventors hope soon to talk through the cable, and send their compli- 

 ments to Queen Victoria. 



