228 Proceedings of Philosophical Societies. [March, 



salts of lead or barytes, and being carefully evaporated, gave 

 ultimately a solid crystalline acid, deliquescing in the cold air, 

 fusing at 212° ; by a higher heat, charring and burning with 

 much dense flame. 



The salts which this acid forms with bases are all soluble in 

 water and in alcohol ; the solutions upon evaporation yield the 

 white salt in a more or less crystalline state, generally unchange- 

 able in the air, when decomposed by heat in tubes giving off 

 much naphthaline and vapour, and leaving a mixture of sulphate 

 and sulphuret. When heated in the air on platinum foil, they 

 burn with much dense flame, almost like naphthaline. 



The analytical experiments were made with the salt of barytes, 

 it being a very constant and permanent substance, capable of 

 being dried perfectly by a heat of 212°, and not undergoing 

 material decomposition below 500°. The quantity of barytes 

 in the salt was ascertained by burning a given weight in a 

 platinum crucible, and heating the residue twice or thrice with 

 the addition of sulphuric acid ; the sulphate of barytes indicated 

 the quantity of barytes present. The quantity of sulphuric acid 

 present was ascertained by mixing a given weight of the salt 

 with carbonate of barytes and oxide of copper, heating the mix- 

 ture to redness in a tube, then acting on the residue by nitro- 

 muriatic acid: collecting the quantity of sulphate of barytes 

 thus produced, it indicated the proportion of sulphuric acid. The 

 carbon and the hydrogen were estimated in the usual way by 

 heating the salt with oxide of copper. By this analysis the 

 elements of the salt approximate closely to 



1 proportional of barytes 78 



2 ditto sulphuric acid 80 



20 ditto carbon 120 



8 ditto hydrogen 8 



Abstracting the barytes, the remaining elements indicate the 

 composition of the pure acid, which thus appears to contain 

 above three-fifths of hydrocarbon ; and in this state of combina- 

 tion, the powers of the sulphuric acid are so far reduced or 

 neutralized by the presence of the hydrocarbon as to have the 

 saturating power of one proportional only, though two propor- 

 tionals are present — a fact also previously observed by Mr. Hen- 

 nel, in the substance called sulphovinous acid. 



The name of Sulpho-naphthalic acid has been given to this 

 compound, as sufficiently indicating its source and nature, with- 

 out involving theoretical views. 



A paper. On the Circle of Nerves which connect the Voluntary 

 Muscles with the Brain ; by Charles Bell, Esq. FRSE. commu- 

 nicated by the President, was also read. 



Feb. 23.— A paper was read, entitled " An Account of a new 

 Reflecting Curve ; with its Application in the Construction of a 



