PRACTICAL STANDARDS FOR ELECTRICATi MEASUREMENTS. 147 



In consequence of his appointment as Treasurer of the Association, 

 Professor Carey Foster has resigned the position of Chairman of the 

 Committee, which he has held for many years. The Committee in asking 

 for reappointment recommend that Lord Rayleigh be the Chairman. 



The standards of the Association have, since the opening of the Caven- 

 dish Laboratory, been kept at Cambridge in the custody of the Secretary. 

 Mr. Glazebrook has now left Cambridge for Liverpool, and the Committee 

 at a meeting in London agreed that Mr. Glazebrook be authorised and 

 requested to retain the custody of the standards. In consequence, the 

 various standards will in the course of the autumn be installed in the 

 Laboratory of University College, Liverpool. 



At the Toronto Meeting the Committee agreed that it was a matter of 

 urgent importance that the general question of the absolute measurement 

 of electric currents should be investigated, and a grant of 75^. was made 

 for the purpose. 



During the year Professors Ayrton and J. V. Jones have concluded 

 some preliminary experiments with this object, and have designed a form 

 of current weighing apparatus calculated to give results of great accuracy. 

 Drawings of the apparatus have been laid before the Committee and the 

 details of its working explained to them. The estimated cost of the 

 apparatus is 280/. ; to meet this the grant of 751. made last year remains 

 in hand. 



After careful consideration and discussion the Committee, at their 

 meeting at Bristol, agreed unanimously to the following resolution : — 



The Committee, having heard from Professors Ayrton and J. V. Jones 

 an account of their preliminary experiments on the absolute determination 

 of the ampere and their plans for the construction of an absolute ampere 

 balance, are of opinion that, in view of the importance of the proposed 

 experiments, application should be made for leave to retain the unexpended 

 balance, 751., of the grant made last year, together with a further grant 

 of 225/. 



Accordingly the Committee ask for reappointment and apply for the 

 above grant. They recommend that Lord Rayleigh be Chairman, and 

 Mr. R. T. Glazebrook Secretary. 



APPENDIX L 



Comparison of the Standard Coils used by Professors J. Viriamu Jonss 

 and W. E. Ayrton in their determination of the absolute resistance of 

 Mercury with the standards of the Association. By R. T. Glaze- 

 brook, F.R.S. 



These coils consist of two tenth-ohm standards of manganine, and two 

 tenth-ohm standards of platinum silver. 



The method employed in comparing the tenth-ohm standard is de- 

 scribed in the Report of the Committee for 1894 (Oxford Meeting) ' Re- 

 port,' p. 1 28. In certain of the experiments the same mercury cups were 

 used as in 1894 ; in others, the cups used by Professor J. V". Jones in his 

 absolute measurements were employed. The Standard Coils made use of 

 were the following :— Elliott, No. 269 ; Elliott, No. 270 ; and Nalder, 

 3716, the last being a ten-ohm standard, the others units. 



The following values were found : — 



l3 



