228 Proceedings of Phiiosophical Societies, [March* 



Feb. 8. — A paper was read, on the Fossil Bones found in the 

 limestone Rock at Plymouth, by Mr. Whidby. 

 J. At the same meetnig, a paper, by Dr. Henry, of Manchester^ 

 was partly read, on the Aeriform Compounds of Charcoal and 

 Hydrogen, with some additional Expernnents on tlie Gases from 

 Od and Coal. 



Fch. 15. — The paper, by Dr. Henry, on the Aeriform Com- 

 pounds of Charcoal and Hydrogen, was resumed. 



At the same meeting, a ))apcr was read, by the Rev. Dr. 

 Robertson, entitled, " Observations of the Eclipse of the Sua 

 on Sept. 7, 18-20." 



At the same meeting also a notice was read, respecting a lunar 

 Volcano, by Capt. H. Kater. 



Capt. K. first observed this volcano on Sunday, Feb. 4, tha 

 moon being then two days old ; its appearance was that of a 

 small nebula, of variable brightness, subtending an angle of 3" 

 or 4'". Its distance from the edge of the moon was 1-iOth her 

 <Jiameter ; and on the 6th, the angle it formed with a line joia- * 

 ing the cusps was about 50°. 



Feb. 22. — Dr. Hemy*s paper, on the Aeriform Compounds of 

 Charcoal and Hydrogen, was concluded. 



The object first proposed by the author was to examine the' 

 accuracy of those views of the compounds of charcoal and hydro-.' 

 gen which had arisen out of his former experiments, and those of 

 Mr. Dalton, cspecally whether there be a compound answering in 

 its characters to light carburetted hydrog'^n gas, the existence 

 qC which had been called in question in a late Bakerian lecture. 

 This, after attentively, and at various times, examining the gas 

 from stagnant water, he pronounces to be a distinct chemical 

 compound, having uniformly the same composition and chemical 

 properties, and the same specific gravity (0*556). It is consti- 

 tuted of loo parts by weight of charcoal united with 33*40 of 

 hydrogen; while oleHant gas consists of lOv) charcoal + 16-70 

 hydrogen. Hence if the latter be considered as a compound of 

 one atom of charcoal and one atom of hydrogen, carburetted 

 hydrogen must consist of one atom of charcoal and two atoms of 

 hydrogen; and as 100 cubic inches of carburetted hydrogen 

 contain hydrogen equivalent to 200 cubic inches of hydrogen gas, 

 he suggests the verification of the specific gravity of hydrogen 

 gas by that of carburetted hydrogen, and finds that in this way- 

 it comes out 0*0698, making the relative weights of the atoms of 

 hydrogen and oxygen very nearly as 1 to 8. The atom of char- 

 coal also he estimates from the composition of carburetted 

 hydrogen, and of carbonic acid, at 6. 



His next experiments relate to the best means of analyzing i 

 mixtures of oleHant gas with hydrogen, carburetted hydrogen, 

 or carbonic oxide ; and of olefiant gas with all those three gases. 

 Chlorine, he shows, may be employed with perfect accuracy, 

 provided certaiii. precautions are observed, which are described 



