iv CONTENTS. 
On the most general Motion of an Incompressible Perfect Fluid. By 
Professor Tait, . . . . . . .143 
Address by Professor Wyville Thomson on the “Condition of the 
Depths of the Sea,” . . . . . . 144 
Facts as to Brain- Work ; in Illustration of the New and Old Methods 
of Philosophical Inquiry in Scotland. By Thomas Laycock, M.D., 145 
On Change of Apparent Colour by Obliquity of Vision. By Robert 
H. Bow, C.E., F.R.S.E., ...... 155 
Remarks on the Theories of Capillary Action. By Edward .Sang, 
Esq., F.R.S.E., . . . . . . .160 
Theory of Construction of the Great Pyramid. By John Christie, 
Esq. Communicated by the Rev. W. Lindsay Alexander, D.D., 162 
On the Structure of Tubifex. By W. C. MTntosh, M.D., . . 166 
Primitive Affinity between the Classical and the Low German Lan- 
guages. By the Hon. Lord Neaves, . . . .167 
On the Genetic Succession of Zooids in the Hydroida. By Professor 
Allman, ........ 168 
On Green’s and other Allied Theorems. By Professor Tait, . .168 
Proposed Method of ascertaining the Temperature of Falling Rain. 
By Thomas Stevenson, F.R.S.E., Civil Engineer, . . . 170 
Letter from Professor W. J. Macquorn Rankine as to Diagrams of 
Forces in Framework, . . . . . .171 
On Spectra formed by Doubly Refracting Crystals in Polarised Light. 
By Francis Deas, LL.B., F.R.S.E., .... 172 
On the Heat Disengaged in the Combination of Acids and Bases. 
Second Memoir. By Thomas Andrews, M.D., F.R.S., Hon. F.R.S.E., 174 
Note on Professor Bain’s Theory of Euclid I. 4. By Wm. Robertson 
Smith, M.A., Assistant to the Professor of Natural Philosophy. 
Communicated by Professor Tait, . . . . .176 
A Simple Mode of Approximating to the Wave-Length of Light. By 
W. Leitch, Assistant to the Professor of Natural Philosophy in the 
University of Glasgow. Communicated by Professor Tait, . 179 
Note on Linear Partial Differential Equations. By Professor Tait, . 190 
On the Oxidation Products of Picoline. By James Dewar, F.R.S.E., 
Lecturer on Chemistry, Veterinary College, Edinburgh, . .192 
Notes of some Experiments on the Rate of Flow of Blood and some 
other Liquids through tubes of narrow diameter. By J. Matthews 
Duncan, M.D., F.R.S.E., and Arthur Gamgee, M.D., F.R.S.E., . 193 
On Cystine (C 3 H 7 N0 2 S). By James Dewar, F.R.S.E., Lecturer on 
Chemistry, Veterinary College, Edinburgh, and Arthur Gamgee, 
M.D., F.R.S.E., Lecturer on Physiology, at Surgeon’s Hall, Edin- 
burgh, ........ 201 
Notes from the Physical Laboratory of the University. By Professor 
Tait. (With a Plate), ...... 206 
Donations to the Society, ...... 209 
Opening Address, Session 1870-71. By David Milne Home, Esq., . 232 
Additional Remarks on the Theory of Capillary Attraction. By 
Edward Sang, Esq., ...... 308 
Laboratory Notes : On Thermo-Electricity. By Professor Tait, . 308 
Note on Linear Differential Equations in Quaternions. By Professor 
Tait, . . . . . . . .311 
On some Quaternion Integrals. By Professor Tait, . . .318 
Note on an Ice Calorimeter. By Dr A. Crum Brown, . . 321 
Address “ On the Educational System of Prussia.” By Principal Sir 
Alex. Grant, Bart., ....... 309 
