Popular Science Monthly/Volume 24/April 1884/Photographing a Streak of Lightning

644456Popular Science Monthly Volume 24 April 1884 — Photographing a Streak of Lightning1884Gaston Tissandier



A BOHEMIAN observer, M. Robert Haensel, of Reichenberg, has succeeded in accurately photographing a flash of lightning. His pictures, of which he has taken several, show the light of the flash, under the form of long, continuous sparks, traversing the atmosphere. With the spark the landscape also is well produced, and a means is

Fig. 1.

given for estimating the length of the luminous train, which, in one instance, is calculated to be seventeen hundred metres, or more than a mile.

Wheatstone demonstrated by direct experiments of great ingenuity that single flashes of lightning do not last more than a millionth of a second. We may judge from this of the wonderful sensibility of the new gelatine-bromide plates which permit the taking of correct views under these conditions.

M. Haensel has given a short account of the circumstances under which his photographs were taken and of the processes he employed. On the 6th of July, 1883, during a storm, when the sky was traversed

Fig. 2.

by frequent flashes of lightning, he turned his instrument at about ten o'clock in the evening toward that point whence the strongest flashes seemed to issue. The apparatus was furnished with the most sensitive gelatine-bromide plates, and the flash left its own impression upon them as it was formed. Out of ten plates that were exposed, he obtained only four photographs, of two of which we here give exact copies, taken from heliographic reproductions by M. Gillot, of Paris. The first figure represents two flashes. In the left one will be observed a double spark, which also appears triple in the middle. Simultaneously with this flash the sky was traversed by another, which also appears ramified in even a more complicated manner than its companion. The second figure represents in all its beauty a flash with many extensive and divergent ramifications.—Translated for the Popular Science Monthly from La Nature.