Royal Society of Edinburgh. 313 
ROYAL SOCIETY OF EDINBURGH. 
March 4.—Mr. Allan read a paper on the rocks of the 
environs of Edinburgh, being the first of aseries which he 
proposes to read on that subject. The present one em- 
ice the rocks of St. Leonard’s Hill and Salisbury Craig. 
The specimens illustrating the subject be presented to the 
Society to be deposited in their Cabinet. 
March 18.—Sir George Mackenzie read some geological 
remarks ou the appearances presented by different rocks in 
Iceland; and showed their importance in connecting the 
phenomena of volcanoes with the’ principles of the Hut- 
tonian theory. Sir George brought forward the results of 
Sir James Hall’s experiments on heat modified by com- 
pression, and successfully applied them to support his con- 
clusions. The facts were explained in a satisfactory man- 
ner; and the whole paper was so important in a geological 
point of view, that we regret it is not in our power to give 
an analysis of it. We understand, however, that it will 
form a part of the account of Iceland, which Sir George and 
his friends are about to publish. The work is now in tbe 
press. 
April 1.—Dr. Brewster read a description of a new in- 
sirament for measuring capillary attraction. The instru- 
ment is to be exhibited at a future meeting. 
Professor Playfair read a most interesting paper, being 
part of his new cdition of his illustrations of the’Hutto- 
nian theory, entitled Remarks on the Natural History of 
Volcanoes, ; 
WERNERIAN NATURAL HISTORY SOCIETY. 
At the meeting of this Society, on the 16th of February, 
Professor Jameson read a mineralogical description of the 
romantic and interesting valley of Pentland, near Edinburgh. 
After describing the magnitude and direction of the valley, 
and the shape and height of the mountains surrounding 
jt, the Professor stated as°a probable conjecture, that it was 
formed by a Jake which had emptied iteelf by a laterat valley 
which traverses its south side. He next enumerated and 
described the varicus rocks of which it is composed, and 
gave a-full detail of their geognostic relations. Four sets 
of rocks were described as occurring in this valley; transi- 
tion rocks,——sandstone and conglomerate rocks,—rocks 
_ of trap-taff, —wacke,— amygdaloid, &c.; and rocks of 
the .claystone series, as claystone, porphyroid, compact- 
feldspar, &e. 
At the meeting on the 9th of March, the Secretary read 
pitty commu- 
