Nikola Tesla: Colorado Springs Notes, 1899-1900 Page 387

Colorado Springs

Jan. 7, 1900

Photographs taken with Mr. Alley from Dec. 17 to Dec. 31, 1899 and particulars about the same continued:

LVIII. This photograph shows the extra coil in central view with the discharge issuing from two diametrically opposite wires, pointing upwards, which are fastened to the brass ring or last turn on the top. The sparks, passing abundantly to the hood above the coil, produce a most beautiful symmetrical figure, which is rendered still more so by the fine texture and sharpness of the discharge paths. On the top of the coil from the brass ring delicate streamers rise producing the effect of a flame. The two wires from the ends of which the sparks and streamers sally forth glow all along. This is remarkable and indicates the great quantity of electrical movement. The glow of the top turn of the secondary and also that of the wire leading to the extra coil is strong, that of the latter wire being much stronger. Some exceptionally brilliant sparks occur occasionally. This happens when the discharge breaks out on one wire or point much earlier. In this case the spark continues along this path and practically all the energy supplied goes this way. In the experiment, as in most cases before, 100 throws of the switch were made, other particulars remaining unchanged.

LIX. In this plate the extra coil is again shown in central view, only the discharge is made to issue from many wires instead of only from two as before. The wires are fastened to the brass ring and are pointed upward as in the preceding case. This photograph is also symmetrical and extremely beautiful. Some stronger sparks and streamers occurring occasionally present many features of interest. A number of sparks starting from the back avoid the hood, though passing near the same, circle around and finally strike the hood on the front side. One streamer, extremely long, starts upward following the pole for some distance then turns, passing for a good distance horizontally, and finally darts upward through the opening in the roof, evidently carried by a sudden gust of the draught. Several sparks pass closely to the hood upward and return to the same after traversing a considerable distance. All the wires emitting the streamers glow. Again 100 throws of the switch were made and the vibration, as well as other particulars, remained nearly normal.

LX. This is a very interesting plate, the discharge taking place from a ball of 8" diam. and two diametrically opposite wires fastened to the same. The extra coil is again viewed centrally. Very strong sparks pass to the floor, some twisting and darting about curiously and exhibiting several phenomena described already. Sparks and streamers also pass to hood, roof and sides of the building. Some of the streamers attain great length being thirty feet, at least, in a straight line, while some sparks measure twenty feet or more. These latter are very brilliant and fierce. The upper streamers indicate the existence of a strong current of air created by the heat developed by the discharge. Again 100 throws of the switch were made, other particulars remaining the same.

LXI. This is another most beautiful photograph showing streamers and sparks issuing from a disk facing the camera. The extra coil is viewed centrally, as before, the disk forming the free terminal being on a point of the vertical axis of the coil. It seems that in some quick moving streamers the individual discharges are recorded, at least the texture appears far too fine for the break wheel period. Assume, for example, 4000 breaks per

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