IS 14.] Royal Society. 149 



from solution. He declares that some of the " laves lasaltiques," 

 or «« laves de nature basdltique" of Auvergne, bear the most 

 striking resemblance to the " Imsalte ordinaire " of Germany ; but 

 Jt may be remarked, that even the difference of nomenclature indi- 

 cates that he considered them as of different origin. 



Mr. Daubuisson seems perfectly aware of the difficulty of ac- 

 counting for the production of lava in a granite country, and where 

 the volcanic hills rest immediately on the granite. The granite 

 itself could not afford the lava ; for this contains from 15 to 20 per 

 cent, of iron ; while the granite contains scarcely any. The rocks 

 which afforded the lava must therefore necessarilv be situated below 

 the granite. Yet the granite is, in some of the valleys, observed to 

 be more than 1200 feet thick. 



Article XV. 



Proceedings of Philosophical Societies. 



ROYAL SOCIETY. 



On Thursday the 30th of June, a paper by SirEverard Home, 



Bart, was read, On the Influence of the Nerves on the beating of 

 the Arteries, lie was led to his opinion of this influence, by the 

 case of an officer who had received a ball in the leg. The ball was 

 lodged among the fractured parts of the tibia ; and after its extrac- 

 tion, an attempt was made to remove some parts by the applica- 

 tion of caustic alkali ; but the pain produced was so great that they 

 were obliged to desist. The pain was not in the part to which the 

 alkali was applied, but at some distance, and seemed to result from 

 the violent beating of the arteries. Hence it was ascribed to the 

 action of the alkali on a nerve, and the consequent reaction of this 

 nerve upon the arteries. Upon laying bare the carotid artery of a 

 rabbit, and applying caustic alkali to the intercostal nerve, the 

 artery began to beat violently, and continued to do so for some 

 time. This fact, in the author's opinion, throws considerable light 

 on the action of the arteries in various parts of the animal economy 

 hitherto but imperfectly explained. 



At the same meeting, a paper by Smithson Tennant. Esq., On 

 a Method of economizing Fuel during Distillation, was read. Dr. 

 Black long ago demonstrated, that the quantity of heat requisite to 



water from the common temperature to a boiling heat, is only 

 about ;th of what is requisite to convert it into steam. Hence if 

 ■team be made to ad MI cold water, it speedily raises it to the 

 boiling point : but as it cannot make it boil, water heated by steam 



"«t distil. over in any considerable quantity. Mr. TeniMmt's 



improvement consists in this. The worm of a common still is 



tal through a vessel containing water. This 



