7 21 255.911 25.3 256.061 0.04
8 20 255.921 26.6 256.100 0.02
8 20 255.905 26.6 256.084 0.06
8 20 255.887 26.6 256.066 0.03
-------
Mean = 256.072

In one of the preceding experiments, I compared the two Vt₃ forks while
the standard was tracing its record on the cylinder, and also when it was
in position as for use in the observations. The difference, if any, was
less than .01 vibration per second.


_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.