Various Tesla book cover images

Nikola Tesla Books

Books written by or about Nikola Tesla

Colorado Springs

Jan. 4, 1900

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

XLII. Illustrates a similar view of same apparatus in action. The streamers and sparks are produced by 25 short throws of the switch. The sparks pass to hood, floor and roof. The “splashing” on the floor is plainly visible. Many other features of interest, some of which have been already described, may be observed in the photograph. So for instance, one or two streamers show clearly the phenomenon, which has been dwelt upon already, namely more luminous spots or “balls”. The loss in luminosity of a streamer branching out is also illustrated. To give an idea of the magnitude of the display again a human figure is introduced, this time Mr. Alley sitting. The exposure to arc light was 5 minutes, about half opening of full lens and afterward about one half of the large Eastman powder was set off.

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.

XLIV. This plate shows the extra coil discharging laterally across the shop and to the floor, the streamers and sparks issuing from several thin wires tied together and spread apart on the end. In this experiment several discharges to the floor were so powerful as to actually inflame the wood on the spot where they struck the wood. Several instances of “splashing” on the wood are observed. The splitting or branching is nicely shown in one of the streamers. One of the sparks strikes the wood and disappears emerging again at some distance from the spot, having evidently followed a better conducting path through the wood. A powerful spark passes to the coil on the stand, jumps out and strikes the top wire of the secondary, instead of taking the shorter and easier route along the wire to the ground. Some very curious curves and twists are observed on a number of the sparks and streamers. In the experiment, 100 throws of the switch were made and the particulars were in other respects the same as before, the vibration of the “extra coil” being the normal or nearly so.



Lowercase tau - an irrational constant defined as the ratio of the circumference of a circle to its radius, equal to the radian measure of a full turn; approximately 6.283185307 (equal to 2π, or twice the value of π).
A natural rubber material obtained from Palaquium trees, native to South-east Asia. Gutta-percha made possible practical submarine telegraph cables because it was both waterproof and resistant to seawater as well as being thermoplastic. Gutta-percha's use as an electrical insulator was first suggested by Michael Faraday.
The Habirshaw Electric Cable Company, founded in 1886 by William M. Habirshaw in New York City, New York.
The Brown & Sharpe (B & S) Gauge, also known as the American Wire Gauge (AWG), is the American standard for making/ordering metal sheet and wire sizes.
A traditional general-purpose dry cell battery. Invented by the French engineer Georges Leclanché in 1866.
Refers to Manitou Springs, a small town just six miles west of Colorado Springs, and during Tesla's time there, producer of world-renown bottled water from its natural springs.
A French mineral water bottler.
Lowercase delta letter - used to denote: A change in the value of a variable in calculus. A functional derivative in functional calculus. An auxiliary function in calculus, used to rigorously define the limit or continuity of a given function.
America's oldest existing independent manufacturer of wire and cable, founded in 1878.
Lowercase lambda letter which, in physics and engineering, normally represents wavelength.
The lowercase omega letter, which represents angular velocity in physics.