The aurora so strong telegraph operators in Boston and Portland were able to disconnect their power supplies and still transmit messages

So far, the auroras we've seen have been a fun phenomenon but haven't caused any problems on earth. A series of auroras over several days in 1859, though, was so powerful they knocked out telegraph service across North American and Europe - and even staredt small fires in some telegraph offices, including in Springfield.

The Carrington Event - named for the British astronomer who linked it to large sunspots and a burst of light so strong it temporarily blinded him the day before - did not appear to damage equipment on the American Telegraph Co. line between downtown Boston and Portland, but it did lead to an interesting experiment on both that line and a line between South Braintree and Providence: Operators disconnected the batteries that normally powered the lines and yet were able to continue tapping out messages for as long as two hours, using the electrical current generated in the wires by magnetic waves from the upper atmosphere.

The Sept. 2, 1859 event, still considered the most powerful geomagnetic storm in recorded history - producing displays as far south as Havana and Jamaica - had been preceded a couple days earlier by another round of less intense, but still brilliant - and telegraph-disrupting - auroral displays across North America.

Four months later, the the American Journal of Science and Arts provided a series of accounts by telegraph operators of what had happened, including one by George B. Prescott, telegraph superintendent of the American Telegraph Co.'s Boston office, at 31 State St., who discussed both the Aug. 28 and Sept. 2 events:

The effects of the magnetic storm of August 28, 1859, were apparent upon the wires during a considerable portion of Saturday evening and during the entire day, Sunday. At 6 p.m., the line to New Bedford (60 miles in length, running a little west of south) could be worked only at intervals, although, of course, no signs of the Aurora Borealis were visible to the eye at that hour. The same was true of the wires running east though the state of Maine as well as those running north to Montreal. The wire between Boston and Fall River had no battery connected with it on Sunday, and yet there was a current upon it during the entire day, which caused the keepers of the electro-magnets to open and close as the waves came on and receded. ...

On Friday, September 2d, 1859, upon commencing business at 8 o'clock, A.M. it was found that all the wires running out of the office were so strongly affected by the auroral content as to prevent any business being done, except with great difficulty. At this junction it was suggested that the batteries should be cut off, and the wires simply connected with the earth. The Boston operator accordingly asked the Portland operator to cut off his battery and try to work with the auroral current alone. The Portland operator replied, "I have done so. Will you do the same?" Boston operator answered, "I have cut my battery off and connected the line with the earth. We are working with the current from the Aurora Borealis alone. How do you receive my writing? "Very well indeed," rejoined the Portland operator; "much better than with the batteries on. There is much less variation in the current, and the magnets work steadier. Suppose we continue to work so until the Aurora subsides?" "Agreed," said the Boston operator. "Are you ready for business?" "Yes; go ahead," was the response. The Boston operator then commenced sending private dispatches, which he was able to do much better than when the batteries were on, and continued to use the wire in this manner for about two hours, when, the Aurora having subsided, the batteries were resumed.

While this singular phenomenon was taking place upon the wire between Boston and Portland, the operator at South Braintree - Miss Sarah B. Allen - informed me that she was working the wire between that station and Fall River - a distance of about forty miles south - with the auroral current alone. Since then I have visited Fall River and have the statement verified by the intelligent operator upon the railroad line at the depot in that village. ...

Such was the state of the line upon the 2d of September last, when for nearly two hours, they held communication over the wire with the aid of the celestial batteries alone!

Also providing an account, from a Springfield telegraph office, was J.E. Selden, who discussed the Aug. 28 geomagnetic storm:

On the evening of Aug. 28th, upon the Boston and New York circuit, at one moment there was a very heavy current on the wire, and the next none at all. On the Albany and Springfield circuit, a flash passed across from the break key of the telegraph apparatus to the iron frame, the flame of which was about half the size of an ordinary jet of gas. It was accompanied by a humming sound similar to a heavy current passing between two metal points almost in contact. The head was sufficient to cause the smell of scored wood and paint to be plainly perceptible.

But what did it look like in the sky? Way, way brighter than displays we're getting now. In its next issue, the Journal carried a series of reports, including one from Dr. Henry C. Perkins of Newburyport, who described both nights, starting with the Aug. 28 aurora. Around 9:30 p.m., he reported:

The merry dancers sprang up from the northern heavens, and at 10 P.M. the whole celestial vault was glowing with streamers, crimson, yellow, and white, gathered into waving brilliant folds, a little to the south and east of the zenith, affording a canopy of the richest tints and most magnificent texture. The light was examined by the polariscope, and found not polarized. The stars were so lost amid the effulgence as to render it somewhat difficult to make out the constellations. Print might be read by the aid of a small lens, and the time ascertained from the watch by the simple light of the aurora.

During the evening of Sept. 1st the aurora was quite bright, and about a quarter to one (Sept. 2) it spread very rapidly, and soon enveloped the whole heavens. About about one the spectacle was magnificent, a perfect dome of alternate red and green streamers being formed, and the light being so great that the ordinary print could be read as easily as in the day-time. It continued until morning.