146 



REPORT — 1898. 

 Table. 



No. of Coil 



Elliott, 33.^ 

 EUiott, :522 

 Elliott, 357 

 Elliott, 35G 

 Elliott, 358 

 Nalder, 5329 

 Nalder, 5330 

 Sci. Inst. Co. 

 M airhead, 5271 

 Elliott, 339 

 Paul, 39 

 Paul, 50 

 Nalder, 3873 

 Nalder, 3874 



* No. 459 

 ^ No. 4C0 

 No. 461 



B.A.U. 7. 



No. 462 

 No. 463 

 No. 464 

 No. 465 

 ^ No. 466 

 ^ No. 467 

 ^No. 469 

 No. 470 

 No. 471 



No. 367 



^ No. 362 



No. 468 



Resistance of Coil in Ohins' Temperature 



9-9953 



•099G62 

 9-9938 

 -99921 

 100 (1- 00051) 

 100 (1- -00049) 

 1000 (1- -00083) 

 1-00032 

 •99722 

 •99994 

 10-0029 

 1000 (1-00048) 

 9-9901 

 9-9896 



Resistance in B.A. Units 

 1-00021 



13-4° 

 13-6° 

 13-5° 

 13-6° 

 13-4° 

 12-8° 

 12-6° 

 15.8° 

 159° 

 15-9° 

 166° 

 16-7° 

 13-9° 

 13-9° 



17-1° 



The most interesting of the coils are those numbered |^ 362, 367, 

 389,390. (See Appendix I.) 



Of these ^ 367 and ^ 362 are two ten-ohm coils of platinum silver 

 and Nos. "^ 389 and ^ 390 are two tenth-ohm coils of manganine ; the 

 values of these are given in Appendix I. These were made for Profes- 

 sor J. V. Jones' experiments on the value of the standard of resistance, 

 and were compared with the standards of the Association in 1893 and 

 1894. 



It appears from the further comparisons, an account of which is given 

 in the Appendix to this report, that ^367 has changed by possibly three 

 or four parts in one hundred thousand, but that no appreciable variation 

 has occurred in the other coils. 



The temperature coefficients of the two ten-ohm coils have recently 

 been determined with great care by Mr. M. Solomon in Professor Ayrton's 

 laboratory. An account of the determination is given in Appendix II. 



Another coil of interest is a British Association unit, one of those 

 originally made by Matthiessen in 1862 or 1864, which has been in India 

 since that date. This coil was brought home by Professor R. LI. Jones. A 

 careful comparison with the standards shows that it is correct at 16 3°. 

 According to the stamp on the coil, it -was originally correct at 16-2°. 



