105 
of Edinburgh , Session 1866-67. 
rings meeting from opposite directions ; or in various relative posi- 
tions, so as to give smoke-rings proceeding in paths inclined to 
one another at any angle, and passing one another at various dis- 
tances. An interesting variation of the experiment may be made 
by using clear air without smoke in one of the boxes. The in- 
visible vortex rings projected from it render their existence start- 
lingly sensible, when they come near any of the smoke rings pro- 
ceeding from the other box. 
The following Gentleman was admitted a Fellow of the 
Society : — 
John M. M'Candltsh, Esq., W.S., 
The following Donations to the Society were announced: — 
Proceedings of the Royal Society of London. Yol. XV. No. 89. 
8 vo. — From the Society . 
Proceedings of the Natural History Society of Dublin. Yol. IV. 
Part 3. 8vo. — From the Society. 
Quarterly Journal of the Geological Society, London. Vol. XXIII. 
Part 1. 8 vo. — From the Society. 
Journal of the Chemical Society, London. Yol. Y. No. 1. 8vo. — 
From the Society. 
Ninth Detailed Annual Report of the Registrar-General of Births, 
Deaths, and Marriages in Scotland. Edinburgh, 18G7. 8vo. 
— From the Registrar-General . 
An Elementary Treatise on Quartz and Opal. By George Wm. 
Traill, F.G.S.E. Edinburgh, 1867. 8vo. — From the Author. 
Bulletin de la Societe de Geographie. Paris, Janvier, 1867. 8vo. 
— From the Society. 
Die Urzeit der Erde, gediclit von Franz v. Kobell. Miinchen, 
1856. 8vo. — From the Author. 
Akademische Denkreden von Dr Carl Fr. Ph. v. Martius. Leipzig, 
1866. 8vo. — From the Author. 
VOL. VI. 
0 
