When complete, the wire was rather larger than No. 3, English gauge, but varied in diameter, some being as large as No. 1, and it averaged 525 lb. of copper per mile and = 1.5 ohms. The surface of this wire was, however, large.
Dr. Muirhead estimated its static capacity at about 10 M.F., which subsequent tests proved to be nearly correct.
It will be understood that this static capacity stood in the way of fast transmission.
Resistance and static capacity are the two factors that determine speed of signaling.
The duration of the variable state is in proportion to the square of the length of the conductor, so that the difficulties increase very greatly as the wire is extended beyond ordinary limits. According to Prescott, "The duration of the variable condition in a wire of 500 miles is 250,000 times as long as in a wire of 1 mile."
In other words, a long line retains a charge, and time must be allowed for at least a falling off of the charge to a point indicated by the receiving instrument as zero.
In the construction of the line care was taken to insure the lowest possible resistance through the circuit, even to the furnishing of the river cables with conductors weighing 500 lb. per mile.
Ground wires were placed on every tenth pole.
When the first 100 miles of wire had been strung, I was much encouraged to find that we could telegraph without any difficulty past the average provincial "ground," provided the terminal grounds were good.
When the western end of this remarkable wire reached Olean, N.Y., 400 miles from New York, my assistant, Mr. S.K. Dingle, proceeded to that town with a receiving instrument, and we made the first test.