170 



MR. R. ROUTLEDGE ON THE 



Table III. — Differences from the Readings of the Freely 

 exposed Black Bulb in the Sun. 



Month. 



In vacuo. 



In car- 

 bonic-acid 

 gas. 



In hydro- 

 gen gas. 



In com- 

 pressed air. 



January 



o 

 2'0 



59 



99 



ii'9 



146 



i5-4 

 156 

 15-6 



112 



2-8 



i"5 







4-6 

 8-2 

 8-9 



II'O 



14-9 



156 



13-0 



83 



5-i 

 2-5 



1*2 





 1-3 



4*5 

 7-5 

 6- 9 

 96 



"5 



ii*i 



10-5 



5'6 

 3-6 



2-1 

 12 





 2-0 



59 



7' 1 



77 



9*9 

 12-5 



"*3 



119 

 81 



60 

 2-8 



2"0 



February 



March 



April 



May 



June 



Julv 



August 



September 



October 



November 



December 





Means 



9*47 



7-90 



628 



7"26 



XX. On the Composition of Ammonium Amalgam. 

 By R. Routledge, B.Sc, F.C.S. 



Read October 1st, 1872. 



The substance now known as ammonium amalgam appears 

 to have been first obtained by Seebeck* in the beginning 

 of the year 1808, immediately after Davy had announced 

 his brilliant discovery of the isolation of potassium and 

 sodium by means of the voltaic battery. Seebeck pre- 

 pared the amalgam by placing mercury which formed the 

 negative pole of a battery in contact with moistened car- 

 bonate of ammonia. About the same time Berzelius and 

 Pontinf obtained the like result with solution of ammonia. 



* Annales de Chimie, lxvi. p. 191. 



t Gilb. vi. p. 260, and ' Bibliotheque Britannique,' Nos. 323, 324, p. 122. 



