The London, Edinburgh and Dublin philosophical magazine and journal of science . wo figures of the resistance had to be obtainedby interpolation from the swings of the galvanometer. Thebattery employed was one storage-cell, and the current wascommuted for each observation. With the coils of the gal-vanometer placed in series an alteration of -^ of an ohm inthe box caused a total galvanometer swing of about 116 scale-divisions. Bare Wire for Resistance-coils. The values of the 100 ohm coils are: —No. of Coil. 1 2 3 4 5 6 7 223 9 April 5. April 6. 100-511 100-510 100-967 100-971 100-266 100-300
The London, Edinburgh and Dublin philosophical magazine and journal of science . wo figures of the resistance had to be obtainedby interpolation from the swings of the galvanometer. Thebattery employed was one storage-cell, and the current wascommuted for each observation. With the coils of the gal-vanometer placed in series an alteration of -^ of an ohm inthe box caused a total galvanometer swing of about 116 scale-divisions. Bare Wire for Resistance-coils. The values of the 100 ohm coils are: —No. of Coil. 1 2 3 4 5 6 7 223 9 April 5. April 6. 100-511 100-510 100-967 100-971 100-266 100-300 100-305 100-362 100-365 100-671 100-676 100-603 100-607 100*434 100-435 100-845 100-850 The 100 ohm proportional arms were determined by thesame method as was used for the 100 ohm standard values are :— April 17. April 20. April 21. Mean. 100 in X . 100-224 100-219 100-220 100*221 100 in Y . 100-312 100-314 100-309 100-312 The 1000 ohm coils were also measured on the box the gap A (fig. 4) was placed the 100 ohm standard coil; Fig. 4. ioo Ohmstandard. this, together with the first four dials, formed one arm of aWheatstone bridge ; the two other arms were the 100 ohm coilsin the proportional arms. A single flexible lead connectedthe last coil of the 100 dial with any required coil on the1000 dial. Another lead connected the other terminal of thecoil to be measured to the terminal of the proportional arm current was provided by two values of the 1000 ohm coils are :— 224 Prof. A. McAulay on the Wava-Surface and Rotation April 25. 1 1023-35 2 1027-30 3 942-05 4 1022-04 5 1017-21 6 1032-04 7 1007-41 8 1003-45 9 1026-42 The values of the proportional arms are :— April 27. 1000 in X 947-92 1000 in Y 994-21 My object in giving the whole of the figures relating tothe resistance-coils is to show to what an extent bare wirecoils are to be trusted. Whether the coils retain their valuesas well as the resistance standards of the British
Size: 2164px × 1154px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1840, bookidlondon, booksubjectscience
