118 Correspondence of J. Nickles. 
remember, new, the use of a long thin wire of platinum or silver, 
between the electrodes of a voltaic pile, to regulate and render sensible 
grators more than forty years ago (this Journal, [1] iii, 105, 1821) first 
supplied to the demonstrator the means of obtaining a measurable con- 
trol over the currents of powerful voltaic combinations. In demonstra 
tions of this kind, it has been usual to ignite to full whiteness a wire 
of platinum a millimetre or more in diameter and from one to two metres 
in length.—Eps. : 
Electric Telegraphy :—Submarine communications.—The telegraphie 
cables which unite England and France are quite insufficient for the wants 
of the two countries and now more than ever is it important to increase 
the number of these lines of communication. Soon the two nations will be 
united to each other by thirteen wires, namely : four from Calais to Do 
from Dieppe to New Haven, 
between Valentia and Newfoundland. 
ae French project proposes a line to start from the shores of Brest 
— 
