Second determination.
(Joint work with Professor A.M. Mayer, Stevens Institute, Hoboken.)
The fork was wedged into a wooden support, and the platinum tip allowed to rest on lampblacked paper, wound about a metal cylinder, which was rotated by hand Time was given by a break-circuit clock, the rate of which was ascertained, by comparisons with Western Union time-ball, to be 9.87 seconds. The spark from secondary coil of the inductorium passed from the platinum tip, piercing the paper. The size of the spark was regulated by resistances in primary circuit.
The following is a specimen determination:
Column 1 gives the number of the spark or the number of seconds. Column 2 gives the corresponding number of sinuosities or vibrations. Column 3 gives the difference between the 1st and 7th ÷ 6, 2nd and 8th ÷ 6, etc.
| 1 | 0.3 | 255.83 | |
| 2 | 256.1 | 255.90 | |
| 3 | 511.7 | 255.90 | |
| 4 | 767.9 | 255.93 | |
| 5 | 1023.5 | 255.92 | |
| 6 | 1289.2 | 256.01 | |
| 7 | 1535.3 | 255.95 | |
| ------- | |||
| 8 | 1791.5 | 255.920 | = mean. |
| 9 | 2047.1 | - .028 | = correction for rate. |
| ------- | |||
| 10 | 2303.5 | 255.892 | |
| 11 | 2559.0 | + .180 | = correction for temperature. |
| ------- | |||
| 12 | 2825.3 | 256.072 | = number of vibrations per second at 65° Fahr. |
| 13 | 3071.0 |
In the following résumé, column 1 gives the number of the experiments. Column 2 gives the total number of seconds. Column 3 gives the result not corrected for temperature. Column 4 gives the temperature Fahrenheit. Column 5 gives the final result. Column 6 gives the difference between the greatest and least values:
| 1 | 13 | 255.892 | 80 | 256.072 | 0.18 |
| 2 | 11 | 255.934 | 81 | 256.126 | 0.17 |
| 3 | 13 | 255.899 | 81 | 256.091 | 0.12 |
| 4 | 13 | 255.988 | 75 | 256.108 | 0.13 |
| 5 | 11 | 255.948 | 75 | 256.068 | 0.05 |
| 6 | 12 | 255.970 | 75 | 256.090 | 0.05 |
| 7 | 12 | 255.992 | 75 | 256.112 | 0.20 |
| 8 | 11 | 255.992 | 76 | 256.124 | 0.03 |
| 9 | 11 | 255.888 | 81 | 256.080 | 0.13 |
| 10 | 13 | 255.878 | 81 | 256.070 | 0.13 |
| ------- | |||||
| Mean = | 256.094 |
Effect of Support and of Scraping.
The standard Vt3 fork held in its wooden support was compared with another fork on a resonator loaded with wax and making with standard about five beats per second. The standard was free from the cylinder. The beats were counted by coincidences with the ⅕ second beats of a watch.