702 



REPORT — 1893. 



TUESDAY, SEPTEMBER 19. 

 The following Reports and Papers were read : — 



1. Report of the Electrical Standards Committee. — See Reports, p. 127. 



2. On Standards of Low Electrical Besistance. 

 By Professor J. Viriamu Jones. 



[This paper forms Appendix III. of the Report of the Electrical Standards 

 Committee. — See ReportS; p. 137.] 



3. An Apparatus for Comparing nearly Equal Resistances. 

 By F. H. Nalder. 



The instrument shown fulfils the purpose of commutating the resistances to be 

 compared with respect to the ratio resistance coils and a series of bridge wires, to 

 be used according to the value of the coils under comparison. It consists of 

 copper bars mounted on an ebonite base, and furnished with mercury cups for 

 making the necessary contacts. 



At A Aj and B Bj are the cups for the ratio coils, which are wound upon one 

 bobbin and usually of the value of 1", 10", 100"', and 1,000™ on each side. At 

 I Ij and J Jj are placed the resistances whose difference is to be measured, and at 

 G is the slide wire mounted on a detachable frame, with the key M, which runs on 

 the divided rod L for making contact, 



C D £ F show the commutator connections in the first position, and after com- 

 mutation in the position OiDjEiFj as indicated by the dotted lines. 



