. Carnegie Institution of Washington publication. 106 EXPERIMENTS WITH THE DISPLACEMENT INTERFEROMETER. otherwise have been necessary. The drift was at first marked, but finally subsided to a reasonably small value. The sensitiveness (centimeters of dis- placement per volt) in successive groups of observations was (AV potential increment, AA/" micrometer displacement) A/V/AF=, , , , , , , ; therefore about i. i cm. per volt, equivalent to 3 X io-5 volt per vanish- ing interference ring. In these data some extraneous oscillation of the needle is manifest, which vani
. Carnegie Institution of Washington publication. 106 EXPERIMENTS WITH THE DISPLACEMENT INTERFEROMETER. otherwise have been necessary. The drift was at first marked, but finally subsided to a reasonably small value. The sensitiveness (centimeters of dis- placement per volt) in successive groups of observations was (AV potential increment, AA/" micrometer displacement) A/V/AF=, , , , , , , ; therefore about i. i cm. per volt, equivalent to 3 X io-5 volt per vanish- ing interference ring. In these data some extraneous oscillation of the needle is manifest, which vanishes in consecutive groups of results. The experiment was then repeated with two Zamboni cells charging the needle. This, however, again actually reduced the sensitiveness to A7V/AV = , , , , cm. per volt, in successive groups of observations, a result equivalent to 4 X io~B volt per vanishing ring. The data remained of the same order, whether the needle was charged from above or below, so that it is inherent in the theory of the instrument. On returning to the single Zamboni charging cell, sensitiveness again increased to AA/yAF= , or to about 26Xio~6 volt per ring. The Zamboni cells were now removed and the needle charged from above with the electric- lighting circuit at 250 volts. To obviate the effect of drift, which is liable to be persistently in one direction, observations were taken every min- utes. The sensitiveness in two groups of experi- ments of about 5 observations each was then and cm. per volt, or on the average 24Xio~6 volt per vanishing ring. Many other experiments were made with similar results. The annoyance of a drifting needle, which occurs throughout the above results and which at first seemed to have a definite direction from the dark to the light side of the parallel mirrors, was also. FIG. 65. made the subject of considerable study, sunlight being used to avoid the radia- tions from the body of the electric lamp. In thes
Size: 1145px × 2182px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcarnegie, bookcentury1900, bookdecade1900, bookyear1902
