CONTENTS. 
V 
On a Lower Limit to the Power exerted in the Function of Par- 
turition. By J. Matthews Duncan, M.D., . . . .163 
Some Mathematical Researches. By H. Fox Talbot, Esq., . .165 
On the Small Oscillations of Heterogeneous Interpenetrating Systems 
of Particles, which act upon each other according to Laws depend- 
ent only on their Mutual Distances. By A. R. Catton, M.A., 
Fellow of St John’s College, Cambridge, . . . .165 
Note on a celebrated Geometrical Problem. By Professor Tait, . 165 
On Vortex Motion. By Professor Sir William Thomson, . . 167 
Note on the Radiant Spectrum. By Professor Tait, . . .167 
Note upon a Method of varying Weights by Minute Quantities. By 
J. A. Broun, F.R.S., ...... 167 
On the Diurnal Variation of the Magnetic Declination near the 
Magnetic Equator, and in both Hemispheres. By John 
Allan Broun, F.R.S., late Director of the Observatory of 
His Highness the Maharajah of Travancore, G.C.S.I., at Trevan- 
druni, . . . . . . . .168 
Opening Address, Session 1867-68. By Sir David Brewster, Presi- 
dent. Communicated by Professor Kelland, . . .174 
Donations to the Library, ...... 205 
On Polyzomal Curves, &c. By Professor Cayley. Communicated by 
Professor Tait, . . . . . . .217 
Note on the Hodograph. By Professor Tait, . . . .221 
On the Antiquity of Intellectual Man : from a Practical and Astrono- 
mical point of view. By Professor C. Piazzi Smyth, . . 226 
On the Changes produced by direct Chemical Addition on the Physio- 
logical Action of certain Poisons. By Drs A. Crum Brown and 
Thomas R. Fraser, ....... 228 
On the Burning Mirrors of Archimedes, and on the Concentration of 
Light produced by Reflectors. By John Scott, Esq. Communi- 
cated by Professor Kelland, ..... 232 
On the Great Pyramid of Gizeh, and Professor C. P. Smyth’s Views 
concerning it. By A. D. Wackerbarth, A.M., of Upsala. Com- 
municated by Professor Kelland, .... 235 
On the best Arrangement for producing a Pure Spectrum on a Screen. 
By J. Clerk Maxwell, M.A., F.R.SS. L. & E., . . . 238 
Pyramidal Structures in Egypt and elsewhere ; and the Objects of 
their Erection. By Sir J. Y. Simpson, Bart., . . . 243 
Note on the Occasional Occurrence of the Musculus Rectus Thoracis 
in Man. By Professor Turner, . . . . .268 
Address, at the request of the Council, delivered by the Rev. H. B. 
Tristram on the Recent Scientific Researches in Palestine, . .271 
Obituary Notices. By Professor Playfair, .... 282 
Observations relative to the desirableness of transporting from 
Alexandria to Britain the prostrate Obelisk presented to George IV. 
by Mahomed Ali Pacha. By Colonel Sir J. E. Alexander, 
K. C.L.S., 284 
