ON STANDARDS FOR USE IN ELECTRICAL MEASUREMENTS. 95 
Report of the Committee, consisting of Professor G. Carey Foster, 
Sir WILLIAM THomson, Professor AYRTON, Professor J. PERRY, 
Professor W. G. Apams, Lord RayLeicH, Dr. O. J. Lopar, Dr. 
Joun Hopkinson, Dr. A. Murrueap, Mr. W. H. Preece, Mr. 
HERBERT TAYLor, Professor EVERETT, Professor ScHuUSTER, Dr. 
J. A. FLeminG, Professor G. F. FirzGEraLp, Mr. R. T. Guaze- 
BROOK (Secretary), Professor CurysTaL, Mr. H. TomMuinson, Pro- 
fessor W. GARNETT, Professor J.J. THomson, Mr. W. N. SHaw, 
Mr. J. T. Borromiey, and Mr. T. Gray, appointed for the 
purpose of constructing and issuing Practical Standards for 
use in Electrical Measurements. 
THE work of testing resistance coils has been continued at the Cavendish 
Laboratory. A table of values found for the coils is appended :— 
Legal Ohms. 
No. of Coil 
Resistance in Legal Ohms 
Nalder, 1577 
Nalder, 1578 
Nalder, 1579 
Edison Swan, 16 
Elliott, 229 
Elliott, 230 
Simmons . 
Nalder, 1626 
Nalder, 1627 
Nalder, 1628 
. Nalder, 1580 
Reetecoaeee 
ZAAwWA wm A 
Se Oe OL AO" OS 
A 
2 
«199 
"99981 
1-00089 
100041 
“99846 
1:00028 
1:00021 
“99992 
100045 
1:00056 
1:00058 
100072 
Temperature 
16°-9 
16°-9 
16°-9 
13°9 | 
16°-9 | 
16°°9 
16°8 
15°3 
15°3 
14°-8 
15°°3 
It would be of considerable advantage in the testing if all the coils 
were made of a uniform size. 
The original standards of the Association 
measure 6? inches from the bottom of the case to the underside of the 
horizontal portion of the copper connecting-rods, while the vertical portion 
_of these rods is 8 inches in length. These dimensions should be adopted 
in all coils sent to be tested. If this be done, the baths, &c., made to hold 
the standards hold the coils equally well, and the additional convenience 
in testing is very great. 
The original standards of the Association have again been several 
times compared among themselves. 
The results of the comparisons appear to show that while the coils A, 
B, C, D, E, and Flat have remained constant relative to each other; the 
three platinum silver coils F, G, and H have changed. 
