Never, however, since the establishment of the telegraphic system in this country, have the wires been so greatly affected by the aurora as upon Sunday night, the 28th of August, 1859. Throughout the entire northern portion of the United States and Canada, the lines were rendered useless for all business purposes through its action. So strongly was the atmosphere charged with the electric fluid, that lines or circuits of only twelve miles in length were so seriously affected by it as to render operation difficult, and, at times, impossible.
The effects of this magnetic storm were apparent upon the wires during a considerable portion of Saturday evening, and during the whole of the next day. At 6, P.M., the line between Boston and New Bedford (sixty miles in length) could be worked only at intervals, although, of course, no signs of the aurora were apparent to the eye at that hour. The same was true of the wires running eastward through the State of Maine, as well as those to the north.
The wire between Boston and Fall River had no battery upon it Sunday, and yet there was an artificial current upon it, which increased and decreased in intensity, producing upon the electromagnets in the offices the same effect as would be produced by constantly opening and closing the circuit at intervals of half a minute. This current, which came from the aurora, was strong enough to have worked the line, although not sufficiently steady for regular use.
The current from the aurora borealis comes in waves,--light at first, then stronger, until we have, frequently, a strength of current equal to that produced by a battery of two hundred Grove cups. The waves occupy about fifteen seconds each, ordinarily, but I have known them to last a full minute; though this is rare. As soon as one wave passes, another, of the reverse polarity, always succeeds. I have never known this to fail, and it may be set down as an invariable rule. When the poles of the aurora are in unison with the poles of the current upon the line, its effect is to increase the current; but when they are opposed, the current from the battery is neutralized,--null. These effects were observed at times during Saturday, Saturday evening, and Sunday, but were very marked during Sunday evening.