432 
INDEX. 
L. 
Levellings carried across the Isthmus of Panama, to ascertain the relative height of the 
Pacific Ocean at Panama and of the Atlantic at the mouth of the river Chaores, 59. 
Light. On the law of its partial polarization by reflexion, 69. 
On the structure producing its double refraction, 87. 
On the laws of its polarization by refraction, 133. 
On the action of the second surfaces of transparent plates upon light, 145. 
On the phenomena and laws of its elliptic polarization, 287. 
Light-houses. On their illumination, 383. 
Linear measure. On the error in standards of linear measure arising from the thickness of 
the bar on which they are traced, 359. 
Lister (Joseph Jackson). On some properties in achromatic object-glasses applicable to 
the improvement of the microscope, 187. 
Lloyd (John Augustus, Esq.) Account of levellings carried across the Isthmus of Panama, 
to ascertain the relative height of the Pacific Ocean at Panama, and of the Atlantic at 
the mouth of the river Chagres ; accompanied by geographical and topographical notices 
of the isthmus, 59. 
Lubbock (John William, F.R.S.). On the pendulum, 201. 
Researches in physical astronomy, 327. 
M. 
Magnetic needle. Experiments on the influence of the Aurora Borealis on it, 97. 
Its affection by metalliferous veins in mines, 399. 
Manufacture of glass for optical purposes, 1 . 
Measure (linear). On errors in the standards of, 359. 
Melting point of different metals, 285. 
Metalliferous veins in mines. On their electro-magnetic properties, 399. 
Metals. Expansion of different metals by heat, 270. 
Their action upon light, producing its elliptic polarization, 287. 
Microscope. On its improvement derived from some properties in achromatic object-glasses, 187. 
Mineral waters. On the occurrence of iodine and bromine in some of them, 223. 
Mines. Electro-magnetic properties of metalliferous veins in the Cornish mines, 399. 
Moll (Dr.). Observations on the velocity of sound, 209. 
M orveau (Guyton de). Observations on his proposal for a pyrometer, 257. 
O. 
Object-glasses ( achromatic ). On their properties as applicable to the improvement of the 
microscope, 187. 
Observatories of Greenwich and Altona. Experiments to determine the difference in the 
number of vibrations made by an invariable pendulum at these two places, 239. 
