It is hardly necessary to add here, that the effect of the aurora borealis, or magnetic storm, is totally unlike that of common or free electricity, with which the atmosphere is charged during a thunderstorm. The electricity evolved during a thunder-storm, as soon as it reaches a conductor, explodes with a spark, and becomes at once dissipated. The other, on the contrary, is of very low tension, remains upon the wires sometimes half a minute, produces magnetism, decomposes chemicals, deflects the needle, and is capable of being used for telegraphic purposes, although, of course, imperfectly.
Mr. 0.S. Wood, Superintendent of the Canadian telegraph-lines, says:--"I never, in my experience of fifteen years in the working of telegraph-lines, witnessed anything like the extraordinary effect of the aurora borealis, between Quebec and Father Point, last night. The line was in most perfect order, and well-skilled operators worked incessantly from eight o'clock last evening till one o'clock this morning, to get over, in even a tolerably intelligible form, about four hundred words of the steamer "Indian's" report for the press; but at the latter hour, so completely were the wires under the influence of the aurora borealis, that it was found utterly impossible to communicate between the telegraph-stations, and the line was closed for the night."
We have seen from the foregoing examples that the aurora borealis produces remarkable effects upon the telegraph-lines during its entire manifestation. We have, however, to record yet more wonderful effects of the aurora upon the wires, namely, _the use of the auroral current for transmitting and receiving telegraphic dispatches_. This almost incredible feat was accomplished in the forenoon of September 2, between the hours of half past eight and eleven o'clock, on the wires of the American Telegraph Company between Boston and Portland, and upon the wires of the Old Colony and Fall River Railroad Company between South Braintree and Fall River.
The auroral influence was observed upon all the lines running out of the office in Boston, at the hour of commencing business, (eight o'clock, A. M.,) and it continued so strong up to half past eight as to prevent any business being done; the ordinary current upon the wires being at times neutralized by the magnetism of the aurora, and at other times so greatly augmented as to render operations impracticable. At this juncture it was suggested that the batteries should be cut off, and the wires simply connected with the earth.