100 
Proceedings of the Royal Society 
Ferdinand Mueller, Ph.D,, M.D., &c. Vol. I. Thalamifloras. 
4to . — From the Author. 
Maps of the Ordnance Survey of Scotland. With Catalogue . — From 
Colonel Sir Henry James. 
Monday^ l%th Alarcli 1863. 
Dr CHEISTISON, Yice-President, in the Chair. 
The following Communications were read 
1. On the Polarization of the Atmosphere. By Sir David 
Brewster, K.H., F.K.S. 
2. Concluding Note on the Star Observations at Elchies. 
By Professor C. Piazzi Smyth. 
In the former paper, read in December 1862, the author had 
detailed the points of interest that had been found in discussing the 
angles of position, distances, and magnitudes of certain double 
stars which he observed at Elchies with Mr G-rant’s fine telescope 
in last September ; and he now treated similarly the observations of 
the colours of the stars then and there observed. The chief point 
to notice being, that in certain cases the colours undergo periodi- 
cal variations ; with the star ‘‘ 95 Herculis” in twelve years, almost 
exactly within the tenth part of a year, if older records can be 
trusted to implicitly ; and such periodical change the author con- 
sidered a new feature in this branch of astronomy, and one of a 
most important and hopeful character for observers to follow up in 
future. 
The paper concluded with a well-merited tribute of praise to Mr 
G-rant of Elchies, for his services to science, in planning, causing 
to be made, and then erecting, his large equatorial telescope ; and 
with sincere condolence for his subsequent long illness, “ which 
alone is the cause that he himself has not been the first to contri- 
bute to a learned Society observations, and perhaps discoveries, 
made by himself with the said telescope.” 
