CONTENTS.

Account of the late Earthquake at Demerara. By W. H. Camp-
bell, Esq. Communicated by M. Ponton, Esq.,

Page 1
On the Existence of an Electrical Apparatus in the Flapper Skate
and other Rays. By Dr Stark,

1

Observations on the Comet, visible now or lately in the Constella-

tion of the Whale. By C. Rumker, Esq. Communicated by Sir

T. M. Brisbane, Bart.,

3

On a Possible Explanation of the Adaptation of the Eye to Dis-
tinct Vision at Different Distances. By Professor Forbes,

6

Notice of an Ancient Beach near Stirling. By Charles Maclaren,

Esq.,

7

Farther Remarks on the Electrical Organs of the Rays. By Dr

Stark,

8

Observations on the same subject. By Professor Goodsir,

9
Note on the Form of the Crystalline Lens. By Professor Forbes.
Included in the former Abstract,

9
On the Cause which has produced the Present Form and Condi-

tion of the Earth’s Surface. By Sir George S. Mackenzie, Bart., 9

Some Account of the Magnetic Observatory at Makerstoun, and of

the Observations made there. By J. A. Broun, Esq. Com-

municated by Sir T. M. Brisbane, Bart.,

10

Description of a Sliding Scale for Facilitating the Use of the Moist-

bulb Hygrometer. By James Dalmahoy, Esq.,

13

Account of Experiments to Measure the Direct Force of the

Waves of the Atlantic and German Oceans. By Thomas

Stevenson, Esq. Communicated by David Stevenson, Esq., 13

A Verbal Communication in regard to Chevalier's Experiments on

the Decomposition of certain Salts of Lead by Charcoal. By

Dr Traill,

15
On a Peculiar Modification of the Doubly Refracting structure of
Topaz. By Sir D. Brewster, K.H.,

16
Extracts from Letters to the General Secretary, on the Analogy

of the Structure of some Volcanic Rocks with that of Glaciers.
By C. Darwin, Esq., F.R.S. Specimens were exhibited. With

Observations on the same subject, made by Professor Forbes, 17
Letter from Professor Gordon, of Glasgow, on the subject of the
Viscous Theory of Glaciers. Read by Professor Forbes,

19

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