1884.] On a Gravity DanielVs Cell of small Resistance. 173 



the central image are not comparable, and one of us has a Rutherfurd 

 grating in which the infra-red rays in the 1st order are absent after 

 X9000. In conclusion we may say that the radiation apparently 

 varies as to mq 1 , where m and q are constants and T the temperature. 



XV. " On a Gravity Daniell's Cell of very small Internal Resist- 

 ance." By J. T. BOTTOMLEY. Communicated by Professor 

 Sir WILLIAM THOMSON, F.R.S. Received May 29.. 1884. 



I beg leave to describe a new arrangement of gravity Daniell's 

 cell which I have found manageable and convenient for supplying 



FIG. 1. 



continuously and steadily a very powerful current of electricity. It 

 has proved of great service for graduating ampere-meters and for 

 such purposes. 



