Contents. 
v 
Notice of two Fossil Trees lately uncovered in Craigleith Quarry, near 
Edinburgh. By Sir R. Christison, Bart., President R.S.E., . 104 
On the Formation of Buds and Roots by the Leaves of the Ipecacuan 
Plant ( Cephaelis Ipecacuanha). By Professor Balfour. (With a 
Woodcut), ........ 108 
On the Physiological Action of Light. No. II. By James Dewar, 
Esq. , and John G. M‘Kendrick, M.D., . . . .110 
On the Thermal Influence of Forests. By Robert Louis Stevenson, 
Esq. Communicated by Thomas Stevenson, Esq., . .114 
Observations and Experiments on the Fluid in the Cavities of Calca- 
reous Spar. By Dr James Hunter and Edward Sang, Esq., . 126 
On “ Tait’s Property of the Retina.” By George Forbes, Esq., . 130 
A Theory of Volcanic Eruptions. By Daniel Vaughan, . . 133 
On the Placentation of the Sloths. By Professor Turner, . .134 
On the Anatomy of a new species of Polyodon, the Polyodon Gladius 
of Martens, taken from the river Yang-tsze-Kiang, 450 miles above 
Woosung. Part II., being its Nervous and Muscular Systems. By 
P. D. Handyside, M.D., ...... 136 
On the Placentation of the Seals. By Professor Turner, . .137 
Second Report by the Committee on Boulders appointed by the 
Society. (With a Plate), . . . . . .137 
On the Physiological Action of Light. No. III. By James Dewar, 
Esq., and John C. M‘Kendrick, M.D., .... 179 
On the Thermo-Electric Properties of Pure Nickel. By Professor 
Tait, . . . . . . . .182 
Notice of the Ravages of the Limnoria terebrans on Greenheart 
Timber. By David Stevenson, Esq., Civil Engineer, . . 182 
Election of Office-Bearers, ...... 207 
Laboratory Notes. By Professor Tait — 
1. First Approximation to a Thermo-Electric Diagram, . 208 
2. On the Flow of Water through Fine Tubes, . . 208 
Note on the Transformation of Double and Triple Integrals. By 
Professor Tait, ....... 209 
On the Physiological Action of Ozone. By James Dewar, Esq., 
Lecturer on Chemistry, and John G. M ‘Kendrick, M.D., Physio- 
logical Laboratory, University of Edinburgh, . . .211 
On a Compound formed by the addition of Bromacetic Acid to Sul- 
phide of Methyl, and on some of its Derivatives. By Professor 
Crum Brown and Dr E. A. Letts, . . . .219 
Note on the Various Possible Expressions for the Force exerted by 
an Element of one Linear Conductor on an Element of another. 
By Professor Tait, ....... 220 
Mdress on Ozone, by Professor Andrews, Hon. F.R.S.E., Vice- 
President of Queen’s College, Belfast, .... 229 
A new Method of Determining the Material and Thermal Diffusivities 
of Fluids. By Sir William Thomson, .... 229 
