287 
of Edinburgh, Session 1876-77. 
from 25 to 150 fathoms from the surface, and it is not unusual to 
find besides the normal minimum between 500 and 1000 fathoms, 
a second minimum at 25 or 50 fathoms from the surface. These 
maxima and minima are caused in some cases by currents, and in 
others are the evidence of past wet or dry seasons. In the Southern 
Ocean the surface specific gravity varies between 1-0240 and 1*0250, 
being nearly constant at 1*0250 in localities free from ice; it in- 
creases, however, with the depth, the bottom specific gravity being 
usually T0255 or 1*0256. 
The following Gentlemen were elected Foreign Honorary 
Fellows, to fill up the vacancies caused by the death of 
Adolphe Theodore Brongniart and of Christian Gottfried 
Ehrenberg : — 
Alphonso De Candolle, Geneva. 
Professor Carl Gegenbaur, Heidelberg. 
The following Gentlemen were elected Ordinary Fellows 
of the Society : — 
John Murray. 
Walter Noel Hartley, Chemical Demonstrator, 
King’s College, London. 
Walter Weldon, F.C.S., London. 
Monday , 29 th January 1877. 
Professor KELLANI), Yice-President, in the Chair. 
The following Communications were read : — 
1. Note on the Manganese Nodules found on the Bed of the 
Ocean. By J. Y. Buchanan. 
The manganese nodules occur in greater or less quantity all 
over the ocean-bed, and most abundantly in the Pacific. They 
occur of all sizes, from minute grains to masses of a pound weight, 
and even greater, and form nodular concretions of concentric shells, 
round a nucleus, which is very frequently a piece of pumice or a 
shark’s tooth. Their outside has a peculiar and very characteristic 
mammillated surface, which enables them to be identified at a 
glance. When freshly brought up they are very soft, being easily 
