1Y 
Contents. 
PAGE 
b. On a Mechanism for Integrating the General Linear Differ- 
ential Equation of the Second Order, . . .118 
c. The Electric Conductivity of Nickel. By C. Michie Smith 
and J. Gordon MacGregor, . . . .120 
On the Structure of the Body-wall in the Spionidae. By W. C. 
MTntosh, M.D., ....... 123 
Note on Circular Crystals. By E. W. Dallas, . . .129 
Preliminary Note on the Flame produced by putting Common Salt 
into a Fire. By C. M. Smith. Communicated by Professor 
Tait, ........ 133 
The Annual Periods of Thunder (with Lightning), Lightning (only), 
Hail, and Snow, at Oxford. By Alexander Buchan, M.A., . 135 
Note on the Origin of Thunderstorms. By Professor Tait, . . 136 
An Application of Professor James Thomson’s Integrator to harmonic 
Analyses of Meteorological, Tidal, and other Phenomena, and to 
the Integration of Differential Equations. By Sir W. Thomson, 138 
Note on the Thermo-Electric Position of Cobalt. By Professor Tait, 138 
On a Glass Digester in which to Heat Substances under Pressure. 
By Dr E. A. Letts, ....... 139 
On the Connection between Cohesion, Elasticity, Dilatation, and 
Temperature. By Professor George Forbes, . . .141 
Notice of the Completion of the Works designed by Sir Charles A. 
Hartley, F.B.S.E., for the Improvement of the Danube. By 
David Stevenson, Y.P.B.S.E., . . . . .142 
Chapters on the Mineralogy of Scotland. By Professor Heddle. 
Chapter I. — On the Rhombohedral Carbonates. Communicated 
by Professor Tait, . . . . . . .144 
On Thermo-Dynamic Motivity. By Sir W. Thomson, . . 144 
On the Vortex Theory of Gases, of the Condensation of Gases on 
Solids, and of the Continuity between the Gaseous and Liquid 
State of Matter. Bv Sir W. Thomson, . . . .144 
On two new Laboratory Apparatus. By William Dittmar, . . 144 
On an Improved Form of Galvanic Battery. By J. Cook. Com- 
municated by Professor Tait, . . . . .148 
On the Properties of the Perigon Versor. By G. J. P. Grieve. 
Communicated by Professor Kelland, . . . 149 
Descriptions of some new or imperfectly understood Forms of 
Palaeozoic Corals. By H. Alleyne Nicholson, M.D., D.Sc., 
F.R.S.E., Professor of Natural History in the University of St 
Andrews, and James Thomson, F.G.S., .... 149 
On a Stable and Flexible Arch. By Professor Fleeming Jenkin, . 151 
Is the Gaelic Ossian a Translation from the English ? By Professor 
Blackie, ........ 151 
Notes on Dredging in Madeira. By the Rev. Robert Boog Watson, 
B.A., F.R.S.E., F.G.S., \ .153 
