Reports of the Committee on Electrical Standards 

 appointed by the British Association for the 

 Advancement of Science. A Record of the History 

 of "' Absolute Units" and of Lord Kelvin's work in 

 connexion zuitk these. Reprinted by permission of the 

 Council. 



Demy 8vo. pp. xxiv + 784. With 10 plates and 46 text figures. 

 Price I2s. bd. net. 



Extract from the Introduction 



The original British Association Committee on Standards 

 of Electrical Resistance was appointed at the suggestion of 

 Professor William Thomson (later Lord Kelvin) in 1861 

 and consisted of Professor A. Williamson, F.R.S., Professor 

 C. Wheatstone, F.R.S., Professor VV. Thomson, F.R.S., 

 Professor W. H. Miller, F.R.S., Dr A. Matthiessen, F.R.S., 

 and Mr Fleeming Jenkin. The principal object of the 

 Committee was, first, to determine what would be the most 

 convenient unit of resistance, and second, what would be the 

 best form and material for the standard representing that 



unit From 1862 to 1870 much valuable work was done 



by the Committee which in the interim had been strengthened 

 by the addition of Sir Charles Bright, Professor J. Clerk 

 Maxwell, Mr C. W. Siemens, Mr Balfour Stewart, Mr C. F. 

 Varley, Professor G. Carey Foster, Mr Latimer Clark, Mr D. 

 Forbes, Mr Charles Hockin, Dr Joule, and Dr Esselbach. 

 In addition to dealing with the primary electrical standards 

 the Committee have also considered the subjects of platinum- 

 thermometry, thermal and magnetic units, and physical con- 

 stants in general. During the latter years of the Committee s 

 existence it promoted international uniformity in standards, 

 and for this purpose many experiments were undertaken at 

 the National Physical Laboratory. The appointment by 

 the London Conference of 1908 of an International Scientific 

 Committee of fifteen to direct work in connection with the 

 maintenance of electrical standards relieved the Committee of 

 much of its responsibility. The main objects for which it 

 had been appointed had been achieved ; in all the principal 

 countries of the world the same units of resistance, of current, 

 and of electromotive force had been adopted and the standards 

 in use were practically identical. 



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