54 REPORT — 1900* 



The question of the selection of a wire for the construction of the 

 standards is still under the consideration of the Committee. 



During the summer a very full comparison has been made of the unit 

 resistance coils of the Association, and the opportunity has been taken of 

 comparing these with some coils belonging to the Board of Trade, and 

 with others which have recently been obtained from the E.eichsanstalt. 

 The coils were also compared with one of the mercury resistance tubes 

 prepared by M. Benoit in 1885, and which has been in the care of the 

 Secretary since that date. 



The results have not yet been completely worked out, and publication 

 is, therefore, necessarily deferred. Moreover, the temperature during 

 July was very high, so that the mean temperature of the observations is 

 much above that at which previous comparisons have been made. For 

 the purpose, therefore, of connecting these results with the past it will be 

 desirable to make some further observations in the autumn. 



It seemed desirable to set up some mercury resistance tubes in 

 England, with a view of keeping a check on the variations of the wire 

 standards. 



Preparations have been made for this. A number of selected tubes of 

 ' verre dur ' have been obtained, with the kind assistance of the officials 

 of the Bureau International, from M. Baudin, while other tubes of Jena 

 glass have been procured from Schott & Co. Steps ai'e being taken to 

 have some of the best of these calibrated. 



Some advance has been made during the year with the construction 

 of the Ampere balance. The Committee greatly regret the serious illness 

 of Prof. J. V. Jones, which has prevented more rapid progress. The 

 stand for raising and lowering the outer coils has been completed. 

 Thanks to the generosity of Sir A. Noble, the cost of this, estimated at 

 about 1001., has been saved the Committee. 



During the spring the Secretary, as Director of the National Physical 

 Laboratory, visited the Bureau International at Paris and the Reichs- 

 anstalt at Berlin. The Committee are glad to put on record their 

 appreciation of the great courtesy and kindness with which lie was 

 received by President Kohlrausch, M. Benoit, and the other officials con- 

 nected with those institutions. 



The Committee are informed that at the recent International Electrical 

 Congress at Paris the two following resolutions wei-e unanimously adopted 

 by Section I, and confirmed by the Congress and by the Chamber of 

 Government Delegates : — ■ 



1. The Section recommends the adoption of the name of Gauss for 

 the C.G.S. unit of magnetic field. 



2. The Section recommends the adoption of the name of Maxwell for 

 the C.G.S. unit of magnetic flux. 



The question of giving names to the units of magnetic force and flux 

 has been before the Committee on several occasions. The Committee 

 therefore were in a position to welcome cordially these resolutions, and at 

 their last meeting agreed unanimously to a resolution adopting the two 

 names selected by the Paris Congress. 



Of the sum of 251. voted last year, 13/. 7s. 7d. has been expended on 

 material for the new platinum thermometers and on the transport of the ap- 

 paratus from Liverpool to Richmond. If the plan of constructing standards 

 for platinum thermometers is adopted, it will be necessary to purchase a 

 large stock of suitable Avire, the whole of which should be made at the 

 same time. For this a considei'able expenditure will be required ; there 



