4i8 



THE BRITISH ASSOCIATION 



Table I. 

 Comparison of B.A. Units to be deposited at Kew Observatory. 



By C. Hockin. 



The following table shows the value of the different copies of the B.A. 

 units that have been made for preservation at Kew : 



Material of Coil. 



Platinum-iridium alloy 



Platinum-iridium alloy 

 Gold-silver alloy . 

 Gold-silver alloy . 



Platinum 



Platinum 



Platinum-silver alloy 



Mercury 



Mercury 

 Mercury 



No. of 

 Coil. 



lO 



58 



35 



36 



43 



II. 



III. 



Date of Observation. 



[January 4 

 j June 6 



I February 10 



f January 4 

 \ June 6 



(February 10 



I January . 5 

 [February 10 



f April 10 



June 6 



February 10 



January 7 

 August 1 8 

 February 10 



January 7 

 August 18 

 February 10 



[February 15 

 I March 9 

 (February 10 



( February 2 



July 18 



(February 11 



[ February 3 

 -August 18 

 (February 11 



86s 

 865 

 867 



865 

 865 

 867 



865 

 867 



865 

 865 

 867 



865 

 866 

 867 



865 

 866 

 867 



865 

 865 

 867 



86s 

 866 

 867 



86s 

 866 

 867 



Tempera- 

 tures at 

 which 

 Coil has 

 a Resist- 

 ance 



— 10' — 



February 11, 1867 



C. 



5-5 

 6-0 

 6-0 



5-3 

 5-3 

 5-3 



5-7 

 5-7 

 5-7 



5-5 

 5-S 

 5-7 



5-2 

 5-2 

 5-2 



6-0 

 6-0 



6-7 



4-8 



4-8 

 4-8 



17-9 



