Contents. v 
PAGE 
Observations on Boulders and Drift on the Pentland Hills. By 
Alexander Somervail, Edinburgh, . . . . .186 
Notes on Drift and Glacial Phenomena on the Pentland Hills. By 
John Henderson, Curator of the Phrenological Museum, Edinburgh, 187 
References, by Dr Charles Maclaren and Professor Geikie, to Striae 
and Boulders on the Pentlands, . . . . .189 
Remarks on the Boulder Report. By D. Milne Home, LL.D., . 192 
Quaternion Investigations connected with Minding’s Theorem. By 
Professor Tait, ....... 200 
The Pituri Poison of Australia ( Duboisia Hopwoodii, F. Mueller) : 
its Physiological Action and Active Principle. By Dr Thomas 
R. Fraser, Professor of Materia Medica in the University of Edin- 
burgh, ........ 200 
On the Structure and Affinities of the Platisomidae. By Dr 
F. Traquair, ........ 202 
Note on the Probability that a Marriage entered into by a Man above 
the age of 40 will be Fruitful. By Thomas Bond Sprague, M.A., 
Plate XIV., ........ 202 
N otice of the Death of the President of the Society. By Sir Alex- 
ander Grant, Bart., Vice-President, .... 208 
Why the Barometer does not always indicate the Real Weight of the 
Mass of Atmosphere aloft : a continuation of the Paper on this 
subject laid before the Society in Session 1876 and 1877. By 
Robert Tennent, . . . . . . .212 
On some New Bases of the Leucoline Series. Part II. By G. Carr 
Robinson and W. L. Goodwin, ..... 224 
On a Calculus of Relationship. By Alex. Macfarlane, M.A., D.Sc., 224 
On the Carboniferous Volcanic Rocks of the Basin of the Firth of 
Forth : their Structure in the Field and under the Microscope. 
Second Paper. By Professor Geikie, . . . .232 
Additional Observations on the Fungus Disease J affecting Salmon 
and other Fish. By A. B. Stirling, Assistant Curator of the 
Anatomical Museum of the University of Edinburgh, . . 232 
On the Form and Structure of the Teeth of Mesoplodon Layardii 
and Mesoplodon Sowerbyii. By Professor Turner, M.B., . . 250 
Atomicity or Valence of Elementary Atoms : Is it constant or 
variable ? By Professor Crum Brown, . . . .252 
Action of Heat on some Salts of Trimethyl-sulphine. No. IV. By 
Professor Crum Brown and J. Adrian Blaikie, D.Sc., . . 253 
Comparison of the Salts of Diethylmethyl-sulphine and Ethyl- 
methylethyl-sulphine. By Professor Crum Brown and J. Adrian 
Blaikie, D.Sc., . . . . . . 254 
On the Bursting of Firearms when the Muzzle is closed by Snow, 
Earth, Grease, &c. By Professor George Forbes, . . . 254 
On some New Bases of the Leucoline Series. Part III. By G. Carr 
Robinson and W. L. Goodwin, ..... 256 
Notice of Striated Rocks in East Lothian and some of the adjoining 
Counties. By David Milne Home, LL.D., . . . 256 
