140 Proceedings of Philosophical Societies. {Ave, 
rock is for the most part a compact, sonorous, dark blue trap, nearly 
with them. He. laid bare the carotid artery of a dog, and upon 
touching the intercostal nerve and par vagum with potash, a violent 
increase in the action of the artery took place. The same experi- 
ment succeeded equally in rabbits; so that the circulation of the 
blood is not wholly dependant upon the heart and the elasticity of 
the arteries, the action of the nerves is necessary to regulate the 
distribution of it to the different parts of the body. 
© XVIL. On the Means of producing a double Distillation by the 
same Hect. By Smithson Tennant, Esq. F.R.S.—The method is 
to make the worm from the first still pass through a second, which 
is air-tight, and has attached to it a worm connecting it with an air- 
tight receiver. Heat is applied to the second still till the liquid in 
it is made to boil; the cocks are then shut, and the distillation 
carried on by the heat communicated by the worm from the first 
still. 
XVIII. An Account of some Experiments on Animal Heat. By 
John Davy, M.D. F.R.S.—From these experiments it appears 
that there is no material difference between the specific heats of 
veinous and arterial blood, except what arises from difference in the 
specific gravity; that of the former being 1°049, and of the latter 
1:050. Our author considers the relative specific heats as 0°913 
and 0903. The temperature of arterial blood is higher than that 
of venous, and the temperature of the left side of the heart than of 
the right. The temperature of parts diminishes as the distance of 
the parts from the heart. These results are incompatible with Dr. 
Crawford’s theory of animal heat, but agree with the theory of Dr, 
Black. 
ARTICLE X. 
Proceedings of Philosophical Societies. 
GEOLOGICAL SOCIETY, 
May 19—A notice accompanying an additional drawing to the 
paper on Vegetable Remains in Chalcedony, by Dr. Macculloch, 
was read, describing a vegetable remain possessing decidedly the 
genuine characters of conferva. 
June 2.—The Secretary reported that a communication on the 
Native Tellurium of Norway had been received from Professor 
‘smark, of Christiana. 
Dr. Macculloch’s paper on the Isle of Sky, begun at a former 
meeting, was concluded. 
The principal group of mountains in Sky is the Cuchullin. This 
elevation probably exceeds 3000 feet, and the principal escarpments 
Jook east and north. It is remarkable for the spiry granitic form of 
its summits, and its naked barrenness, owing to the strong resist- 
ance which it opposes to the usual causes of decomposition. ‘The 
