Geology and Geography. 351 



tity of fuel, and thus reducing* it to tlie metallic state without fa- 

 sion. 



Mr Johnston described Paracyanogen and its compounds. 



Mr West next read a short paper, the object of which was to sug- 

 gest a new mode of determining the presence, and estimating the 

 amount, of those materials which constitute but small fractional por- 

 tions of the atmosphere. His proposition was, that instead of ope- 

 rating upon a limited volume of air, as is usually done, a very large 

 quantity of it should be made by mechanical means to pass through 

 appropriate fluids — such as barytic water for carbonic acid, and ni- 

 trate of silver when the object was to detennine the presence of 

 muriatic acid Dr Dalton stated that he had for many years turn- 

 ed his attention to the amount of carbonic acid in the atmosphere, 

 and that he had satisfied himself that its average quantity was one 

 part in 1100. He altogether rejected the results of Saussure, and 

 contended that the quantity of this gas in the atmosphere was con- 

 stantly the same in town and country^ and that even in a crowd- 

 ed theatre it seldom rises to one per cent — Dr Thomson gave it as 

 his opinion, that a fall of rain diminished the amount of carbonic 

 acid in the air, and expressed surprise that Dr Dalton should main- 

 tain an opposite tenet. 



The business of the day was concluded by Dr Hare reading a 

 pamphlet on the Berzelian nomenclature, which he addressed some 

 years since to Professor Silliman. 



Section C. — Geology and Geography. 



Mr Stutchbury read a paper by himself and Dr Riley on some 

 newly-discovered Saurian Remains, from the magnesian conglo- 

 merate of Durdham Down. This communication chiefly related 

 to the specimens exhibited to the meeting, and contained a number 

 of minute anatomical details, which testified in a high degree the 

 industry of Dr Riley and Mr Stutchbury, who had examined the 

 specimens ; but it would be impossible, without plates, to convey to 

 the reader any accurate notion of these highly-interesting organic 

 remains. They belong to two new genera established by Dr Riley 

 and Mr Stutchbury, the Palaosaurus B,nd Thecodontosaurus ; and 

 were found in the magnesian conglomerate which at Durdham 

 Down reposes on the carboniferous limestone. They must have 

 been deposited upon the spot where they were found without vio- 

 lent action, as they bear no marks of attrition. Perhaps the most 

 interesting fact mentioned was the peculiar structure of the verte- 



Aa2 



