Nikola Tesla Books
Books written by or about Nikola Tesla
Note: As repeatedly observed, the first addition of a small length of wire to a coil generally produces a great effect but a certain small length being bypassed the increase per unit of length becomes more gradual.
Experiments with coil 346 turns on drum 14" diam. with the view of investigating influence of elevation upon the capacity of a body connected to earth continued. This time in connection with the vertical wire a ball 30" diam. was used in the manner before described.
Coil with spark wires alone
| Capacity in primary circuit total | Turns in regulating coil + connections } Inductance | Analyzing spark on terminals of excited coil |
|---|---|---|
| $! {{\left({3 \times 36}\right) -2} \over 2} $! = 53 bottles = 0.0479 mfd | 3 5/8 + conn. | 3 1/8" |
Coil with 50 feet wire No. 10 vertical
| 0.0479 mfd | 7 3/4 + conn. | 4" |
Coil with ball 30" diam. lowest position 10'3" from center to ground
| 0.0479 mfd | 8 1/2 + conn. | 4 1/8" |
Coil with ball mean position 33'9" from center to ground
| 0.0479 mfd | 8 7/8 + conn. | 4 1/4" |
Coil with ball highest position 57'3" from center to ground
| 0.0479 mfd | 9 1/4 + conn. | 4 3/8" |
Note: The excitation in this and previous case was as before described by connecting the lower terminal of coil to that terminal of the condensers (primary) which was connected to small adjustable spark gap, specially made for this purpose, to earth.
It would be desirable in these tests to do away with the spark wires as these are apt to introduce errors in the estimates of capacity. Experiments were made with new extra coil to see how close the maximum rise could be ascertained without any spark wires, merely by observing the streamers. For this purpose the extra coil was excited from the secondary of oscillator as in some previous instances. First the extra coil was tuned with spark wires, then the upper wire which is the only one of importance was taken off and the system again tuned. The results were as follows:
New Extra coil with Spark wires Guttapercha No. 26, 24 feet long
| Capacity in primary circuit total | Inductance in primary circuit Turns of regul. coil+connections | |
|---|---|---|
| bottles | mfd | |
| $! {{\left({8 \times 36}\right) -2} \over 2} $! = 143 bottles | = 0.1287 | 7 5/8 + connections |
257
November 3
A repeated measurement of the capacity of the vertical wire and the 30" sphere by the method of October 29th but with a new coil L (see October 31st). A new feature is Teslaâs attempt to eliminate the wires of the spark gap, estimating the excitation solely from the streamers.
November 3
He measures the capacitance of the vertical wire and sphere of 30" in diameter again by following the method of Oct. 29 but with new coil L (please see Oct. 31). that he attempts to eliminate the wires of the measuring arc gap and that for pose of finding the resonance he uses the current streamers indication.
