72 



Mr, JL T. Glazebrook on the Vulue of 



bridge-wire is known at 15°, this required, when the tempe- 

 rature of the room was as low as 1° or 2°, correcting for 

 temperature ; but as the whole correction amounted to less 

 than 2 per cent, of the bridge-wire used, while this again was 

 only 1*5 per cent, of the resistance measured, no very accurate 

 knowledge of the temperature of the wire was needed. In 

 some cases a coil of 100 B.A. units was put in multiple arc 

 with the mercury tube; and the resistance of the combination, 

 which amounted to a little over 1 B.A. unit, was compared 

 with the wire standard. 



The results of the comparisons are given in the following 

 Tables. 





Table I.— Tube, Benoit No. 37. 





Date. 



Standard. 



Notes. 



Yalue in 

 B.A. units. 



Jan. 3 



„ 5 



„ 5 



„ 6 



„ 6 



„ 7 



,, 7 



,. 7 



Flat. 

 Flat. 

 Flat. 



Flat. 

 Flat. 

 Flat. 

 Flat. 

 Flat. 





1-01111 

 1-01103 

 1-01108 



1-01099 

 1-01101 

 101109 

 1-01109 

 1-01106 





100 B.A. units in multiple arc with 

 tube. 



Mercury drawn through. 



Mercury drawn through. 

 After interval of 1 hour. 



Mean for No. 37 1*01106 B.A. units. 





Table II.— Tube, Benoit No. 39. 





Date. 



Standard. 



Notes. 



"Value in 

 B.A. units. 



Jan. 3 



» o 



,, 5 



„ 6 



» 6. 



„ 7 



„ 7 



„ 7 



„ 8 



„ 8 



„ 8 



Flat. 

 Flat. 

 Flat. 



Flat. 



Flat. 

 Flat. 

 Flat. 

 Flat. 

 Flat. 

 Flat. 

 Flat. 





1-01053 

 1-01058 

 1-01060 



1-01049 



1-01037 

 101041 

 1-01034 

 101029 

 101022 

 1-01027 

 101033 





100 B.A. units in multiple arc 

 with tube. 



Mercury drawn through. 



Mercury drawn through. 

 After interval of 1 hour. 



Mercury dr;„Avn through. 

 After interval of 1 hour. 



Mean of last seven for No. 39 1-01032. 



With regard to the observations on No. 37, it will be seen 

 that they are extremely close, the greatest difference between 



