Nikola Tesla Books
Jan. 4, 1900
Photographs taken with Mr. Alley from Dec. 17 to Dec. 31, 1899 and particulars about the same:
XLIII. This shows again the same discharge laterally across the shop, as before. The sparks are more powerful this time and there are more of them, fifty throws of the switch being made. The sparks and streamers are made to issue this time from a curved wire forming the terminal of the extra coil. The sparks to the hood and to the roof are particularly interesting. The point used before on the ball 30" diam. was taken off. The extra coil unfortunately broke through some places and also to the floor.
Some of the streamers form actual loops turning back upon themselves. A curious feature is presented by a long streamer striking the wooden support of the ball and splashing from there upon the ground wire leading from the ball. Some streamers are seen to pass along the wire without striking the same, lighting finally on the ball. This plainly illustrates that the path of such a discharge is accidental, dependent on the arrangement of particles floating in the air on the currents in the latter. Luminous points are again observed on some of the streamers, as in previous instances. In this experiment the other particulars were the same as before. Mr. Alley was photographed once more, a flash being used after the arc light exposure as in the preceding case.