## Nikola Tesla Books

Books written by or about Nikola Tesla

# Nikola Tesla: Colorado Springs Notes, 1899-1900Page 145

August 10-11, 1899

In Diagram 2. two condensers C and C1 are placed in series, one of them being shunted by graduated self-induction l and battery B1. The other condenser C, being larger, allows the current from battery B to pass through break and coil l when device a is excited. Not very good. A modified plan is illustrated in 3. In this case the auxiliary battery B1 charges the two condensers C and C1 in series, whereupon one of them is discharged through the break d. This is fair.

In 4. the battery (main) is so placed that a high e.m.f. is charging the condenser yet current through the sensitive device is small.

Aug. 11, 1899

Measurement of capacity of the new condensers prepared from Maniton Water bottles.

With the exception of three tanks in which bottles with green glass were used all the remaining bottles were of dark glass. The test did not show much difference between the two kinds of glass and all the tanks separately measured were found to be, after proper filling in of the solution, of the same capacity or very nearly so. All the bottles were first connected in quantity and the capacity compared with that of 1/2 mfd. standard condenser. The deflections were almost exactly as 36:44, 36° for the 1/2 mfd. and 44° for the bottles. The capacity of all the latter was therefore $! {11 \over 18}$! = 0.611 mfd. This would give for one bottle, since there were 576 bottles, the average value of $! {11 \over {18 \times 576}}$! = 0.00106 mfd. or 0.00106 x 9 x 105 = 955 cm. As there are 36 bottles in each of the tanks we get for one tank 36 x 0.00106 = 0.03816 mfd. or 36 x 955 = 34,380 cm. As each side has 8 tanks the capacity of each side would be 0.03816 x 8 = 0.30528 mfd. or 275,040 cm. and when, as mostly the case, the two sides are in series the total primary capacity will be $! {0.611 \over 4}$! = 0.15275 mfd. or 0.15275 x 9 x 105 = 137,475 cm. When working with one primary turn, taking the inductance of primary as $! {7 \over 10^{4}}$! henry we get

$! {T = {{2 \pi \over 10^{3}} \sqrt{0.15275 \times {7 \over 10^{5}}}} = {2.054 \over 10^{5}}}$! and n = 48,700 per sec.

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## Glossary

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 &amp; Sharpe (B &amp; 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&nbsp;angular velocity in physics.&nbsp;