UNIFORMITY OF WEIGHTS AND MEASURES. 375 



M. Kronccker states that the formula (iv) implies the rcsolubility of ^(n, x) 

 into its generic factors, and that conversely the resolution of that equation 

 into its factors implies the possibility of expressing certain solutions (though 

 not necessarily the least solution) of the Pellian equation by means of the 

 modules which admit of complex multiplication. For the case when D=^5, 

 mod 8, he has given the singularly elegant formula 



the first sign of multiplication extending to all numbers less than D and prime 

 to it which satisfy the equations [_J=1, |_^|=— 1; the second to a 



certain sixth part of the modules which admit of complex multiplication with 

 V — D- The formula may also be written in the form 



[T-UA/D] 7 '^ = n.4 K V 2 

 (sec Dirichlet, Crellc, vol. xxi. p. 151). 



Report on the best means of providing for a Uniformity of Weights 

 and Measures, with reference to the Interests of Science. By a 

 Committee, consisting of Lord Wrottesley, D.C.L., F.R.S., The 

 Rt. Hon. C. B. Adderley, M.P., Sir William Armstrong, C.B., 

 F.R.S., The Astronomer Royal, F.R.S., Samuel Brown, W. 

 Ewart, M.P., T. Graham, F.R.S., Sir John Hay, Bart., M.P., 

 F.R.S"., Prof. Hennessy, F.R.S., James Heywood, M.A., F.R.S., 

 Dr. Lee, F.R.S., Dr. Leone Levi, F.S.A., F.S.S., Prof. W. A. 

 Miller, F.R.S., Prof. Rankine, F.R.S., Rev. Dr. Robinson, 

 F.R.S., Colonel Sykes, M.P., F.R.S., W. Tite, M.P., F.R.S., Prof. 

 A. W. Williamson, F.R.S., James Yates, F.R.S., Sir Robert 

 Kane, F.R.S., F. P. Fellows, C. W. Siemens, F.R.S., Matthew 

 Arnold, M.A., Right Hon. Earl Fortescue, and Frederick 

 Purdy, F.S.S. 

 At the Meeting of the British Association, held in Newcastle in 1863, a 

 Committee was appointed to report on the best means of providing for a 

 uniformity of weights and measures, with reference to the interests of science, 

 and a report embodying certain recommendations was presented by the Com- 

 mittee to the British Association, at its last Meeting at Bath, which was 

 received and adopted after considerable discussion in Section F, the Chemical 

 and Mechanical Sections having also had the subject under consideration. 

 The substance of these recommendations was the adoption of a decimal sys- 

 tem of weights and measures, and the choice of the metric system on account 

 of its scientific capabilities ; the use of such metric system, as far possible, 

 in statistical documents and scientific communications ; the placing of metric 

 standards in our public and frequented buildings ; the teaching of the system 

 in schools ; and the use of it at the Custom House and Post Office. On the 

 recommendation of the Section the Committee was then reappointed, and a 

 grant was made to it of .£20. 



