CONTENTS. 
VI I 
Notice respecting Mr Reilly’s Topographical Survey of the Chain of 
Mont Blanc. By Principal Forbes, .... 335 
On the Solution of Perigal’s Problem concerning the contact of 
Epicycloidal Curves. By E. Sang, Esq. . . . 338 
Exhibition of Three Skulls of the Gorilla, received from M. Du 
Chaillu, with Observations relative to their Anatomical Features. 
By Dr Burt and Mr W. Turner, .... 341 
Notice of a Remarkable Piece of Fossil Amber. By Sir David 
Brewster, K.H., F.R.S. ..... 350 
On the Cause and Cure of Cataract. By Sir David Brewster, K.H., 
F.R.SS. Lond. and Edin., ..... 350 
On the Hill Forts, Terraces, and other remains of the Early Races 
in the South of Scotland. By W. Chambers, Esq. of Glenor- 
miston, ....... 351 
On the Molecular Constitution of Organic Compounds, No. I. By 
Alfred R. Catton, B.A., Fellow of St John’s College, Cambridge, 
Assistant to the Professor of Natural Philosophy, . .'353 
Account of the Progress of the Geological Survey in Scotland, 
illustrated by Maps and Sections. By Archibald Geikie, Esq. 355 
On a New Bituminous Substance, imported under the name of Coal, 
from Brazil. By T. C. Archer, Esq., . . . . 364 
Experimental Inquiry into the Laws of Conduction of Heat in 
Bars. Part 11. — On the Conductivity of Wrought Iron, de- 
duced from the Experiments of 1851. By Principal Forbes, . 369 
On the Chemical Composition of the Waters of the Beauly, Inver- 
ness, and Moray Firths. By Dr Stevenson Macadam, . . 370 
On Hemiopsy, or Half Vision. By Sir David Brewster, 
K.H., F.R.S., . . . . . .373 
On the Tertiary Coals of New Zealand. By W. Lauder Lindsay, 
M.D., F.L.S., Honorary Fellow of the Philosophical Institute of 
Canterbur}^, New Zealand, ..... 374 
On the World as a Dynamical and Immaterial World. By Robert 
S. Wyld, Esq., F.R.S.E., . . . , .381 
On the Nudihranchiate Mollusca of St Andrews ; Edwardsia ; 
and the Polyps of Alcyonium digitatum. By W. C. MTntosh, 
M.D., F.L.S. Communicated by Professor Allman. (Accom- 
panied by various Drawings), . . . .387 
Miscellaneous Observations on the Blood. By John Davy, M.D., 
F.R.SS. Lond, and Edin. &c., . . . . 395 
On the Pronunciation of Greek. By Professor Blackie, . 398 
Note on Action. By Professor Tait, .... 404 
On the Application of Hamilton’s Characteristic Function to Special 
Cases of Constraint. By Professor Tait, . . . 407 
On Transversals. By the Rev. Hugh Martin, Free Greyfriars, 408 
On the Motion of a Heavy Body along the circumference of a 
Circle. By Edward Sang, ..... 408 
On the Action of Hydriodic Acid on Mandelic Acid. By Alex. 
Crum Brown, M.D., D.Sc., ..... 409 
On the Nature of Antozone. By Alfred R. Catton, B.A., F.R.S.E., 
Fellow of St John’s College, Cambridge, and Assistant to the 
