The Bridge Method and Periodic Electric Currents. 203 



Observations and Reports (continued). 



Lucknow : North-Western Provinces and Oudh Provincial 

 Museum. Minutes of the Managing Committee. 8vo. Alla- 

 habad 1889. The Museum. 



Madras : Government Observatory. Results of Observations of 

 the Fixed Stars made with the Meridian Circle. 4to. Madras 

 1890. The Observatory. 



Mauritius : Royal Alfred Observatory. Annual Report. 1888. 

 Folio. [1889] ; Mauritius Meteorological Results for 1889. 

 Folio. [1890.] The Observatory. 



Melbourne : Observatory. Report. 1890. Folio. Melbourne ; 

 Monthly Record. July, 1890. 8vo. Melbourne. 



The Observatory. 



New Haven : Observatory of Yale University. Report. 1889-90. 

 8vo. 1890. The Observatory. 



Paris : Ministere de 1'Instruction Publique et des Beaux-Arts. 

 Rapport sur les Observatoires Astronomiques de Province. 

 2 Parts. 8vo. Paris 1889, 1890. The Department. 



February 19, 1891. 

 Sir WILLIAM THOMSON, D.C.L., LL.D., President, in the Chair. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : 







I. " On the Sensitiveness of the Bridge Method in its Appli- 

 cation to Periodic Electric Currents." By LORD RAYLEIGH, 

 Sec. E.S. Received January 17, 1891. 



The most favourable conditions in the ordinary measurement of 

 resistance have been investigated by Schwendler* and by 0. Heavi- 

 side.f It is here proposed to treat the problem more generally, so 

 as to cover the application to conductors endowed with self-induction, 

 or combined with condensers. The receiving instrument may be 

 supposed to be a telephone, which takes the place of the galvanometer 



* " On the Galvanometric Resistance to be employed in Testing with Wheat- 

 stone's Diagram," ' Phil. Mag.,' vol. 31, p. 364, 1866. 



t " On the Best Arrangement of Wheatstone's Bridge for measuring a given 

 Resistance with a given Galvanometer and Battery," ' Phil. Mag.,' vol. 46, p. 114, 

 1873. 



