. Carnegie Institution of Washington publication. Atmospheric-Electric Observations, 1915-16 383 not very desirable in the case of the Einthoven electroscope, or he must make a fresh cah- bration curve each day. Again, the computational work involved in the construction and use of such curves is considerable when much work has to be done. For these reasons the general principle has been adopted of always noting the time taken by the fiber of the electroscope in passing between two fixed readings on the scale of the electroscope. The electroscope system is in each case connected to a potentiome
. Carnegie Institution of Washington publication. Atmospheric-Electric Observations, 1915-16 383 not very desirable in the case of the Einthoven electroscope, or he must make a fresh cah- bration curve each day. Again, the computational work involved in the construction and use of such curves is considerable when much work has to be done. For these reasons the general principle has been adopted of always noting the time taken by the fiber of the electroscope in passing between two fixed readings on the scale of the electroscope. The electroscope system is in each case connected to a potentiometer system used in connection with a voltmeter, so that the electroscopes may be charged to any desired potential. On the completion of the main observations the fixed readings referred to are reproduced, by chai'g- ing the electroscope with the potentiometer, and the corresponding readings in volts are read off from the voltmeter. This throws the constancy of indications on the voltmeter, an instrument which, both as regards the stage of its development and the nature of its. -WWWWWWWV-* Fig. 21.—Wiring Scheme for the Atmospheric-Electric House on the Carnegie. design, is such as to maintain a higher degree of constancy than is required in atmospheric- electric work. The voltmeter used is a minature Weston instrument, with ranges of 3 volts and 150 volts, and the potentiometer system is obtained by utihzing an adjustable resistance. Theoretically one potentiometer system would be sufficient for all the electro- scopes; but in view of the difficulty of even standing still when taking observations in a heavy sea, it is desirable to put the matter of convenience of manipulation in the fore- ground, and a separate potentiometer system is attached to the base of each of the four electroscope systems in use in the observatory. Only the voltmeter is common to all the systems, and this is fixed to the wall in a position convenient for observation from all parts of the room. Figure 2
Size: 1791px × 1395px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcarnegie, bookcentury1900, bookdecade1910, bookyear1917
