INDEX 
TO THE 
PHILOSOPHICAL TRANSACTIONS 
FOR THE YEAR 1830. 
A. 
Achromatic object-glasses. Their application to the improvement of the microscope, 187. 
Altona and Greenwich , [Royal Observatories at). Difference in the number of vibrations 
made by an invariable pendulum at these two places, 239. 
Angular velocities. On the methods best adapted for imparting the greatest, 121. 
Astronomy. Researches in physical astronomy, 327. 
Atlantic. Relative height of the Pacific and Atlantic Oceans, 59. 
Aurora Borealis. Its influence on the magnetic needle, 97. 
B. 
Bakerian lecture on the manufacture of glass for optical purposes, 1. 
Balance of torsion constructed with threads of glass, 215. 
Biot. On elliptic polarization of light, 287. 
Bolton (George Buckley, Esq.). Account of the united Siamese twins, 177. 
Brewster (David, LL.D. F.R.S.). On the law of partial polarization of light by re- 
flexion, 69. 
— On the production of regular double refraction in the 
molecules of bodies by simple pressure ; with observations on the origin of the doubly 
refracting structure, 87. 
— On the laws of the polarization of light by refrac- 
tion, 133. 
On the action of the second surfaces of transparent 
plates upon light, 145. 
■ ■ On the phenomena and laws of elliptic polarization, 
as exhibited in the action of metals upon light, 287. 
Bromine. On its occurrence in certain mineral waters of South Britain, 223. 
