390 Experiments with Grove’s Battery. 
Art. XVI.—E'zperiments made with one hundred pairs of 
Grove’s Battery, passing through one hundred and sixty miles 
of insulated wire ;—in a letter from Prof. 8. F. B. Morse, to 
the Editors, dated New York, Sept. 4th, 1843. 
Dear Sirs,—On the 8th of August having completed my pre- 
parations of one hundred and sixty miles of copper wire for the 
electro-magnetic telegraph which I am constructing for the gov- 
ernment, I invited several scientific friends to witness some ex- 
periments in verification of the law of Lenz, of the action of 
galvanic electricity through wires of great lengths. 
I put in action a cup battery of one hundred pairs, which I had 
constructed, based on the excellent plan of Prof. Grove, but with 
some modifications of my own, economizing the platinum. 
The wire was reeled upon eighty reels, containing two miles 
upon each reel, so that any length from two to one hundred and 
sixty miles could be made at pleasure to constitute the circuit. 
My first trial of the battery was through the entire length of 
one hundred and sixty miles, making of course a circuit of eighty 
miles, and the magnetism induced in my electro-magnet, which 
formed a part of the circuit, was sufficient to move with great 
strength my telegraphic lever. Even forty-eight cups. produced 
action in the lever, but not so promptly or surely. 
We then commenced a series of experiments upon decomposi- 
‘tion at various distances. ‘The battery alone (one hundred pairs) 
gave in the measuring guage in one minute, 5.20 inches of gas. 
When four miles of wire were interposed, the result was 1.20 
inches—ten miles of wire, .57 inch—twenty miles, .30 inch— 
fifty miles, .094. 
The results obtained from a battery of one hundred pairs are 
projected in the following curve. 
