Hence one turn = 0.1307mm.
or = 0.0051 inch.
The length of the steel tape from 0.1 to 99.1 was found to be
greater than 33 yards, by 7.4 turns =.96mm +.003 feet.
Correction for temperature +.003 feet.
Length 100.000 feet.
--------------
Corrected length 100.006 feet.
Determination of the Value of Micrometer.
Two pairs of lines were scratched on one slide of the slit, about 38mm
apart, i.e., from the center of first pair to center of second pair. This
distance was measured at intervals of 1mm through the whole length of the
screw, by bisecting the interval between each two pairs by the vertical
silk fiber at the end of the eye-piece. With these values a curve was
constructed which gave the following values for this distance, which we
shall call D′:
Turns of screw.
At 0 of scale D′ =38.155
10 of scale D′ 38.155
20 of scale D′ 38.150
30 of scale D′ 38 150
40 of scale D′ 38.145
50 of scale D′ 38.140
60 of scale D′ 38.140
70 of scale D′ 38.130
80 of scale D′ 38.130
90 of scale D′ 38.125
100 of scale D′ 38.120
110 of scale D′ 38.110
120 of scale D′ 38.105
130 of scale D′ 38.100
140 of scale D′ 38.100