pie, Gold and Silvei*, Iron and Platinum. His general conclusion 

 is this; That the arranr/ement of condtictors of heat does not 

 differ more from that of conductors of electricity, than either ar- 

 rangement does alone under the hands of different observers. 



2. The reading of a paper by Robert Knox, M.D., 

 F.R.S.E., on the Natural History of the Salmon, was 

 commenced. 



January 21. 



Dii HOPE, Vice-President, in the Chair. 



The following Donation was presented : — 



Tableau de Terrain du Department du Calvados. Par M, He- 

 rault, Ingonieur en Chef du Corps Royal des Mines. — From 

 the Society of Antiquaries. 



The following communications were then read: — 



1. On the Super- Sulphuretted Lead of Dufton. By J. F. 

 W. Johnston, Esq., A.M., F.R.S.E. 



The object of the author of this paper was to shew that the 

 mineral alluded to is «ot a new atomic compound, but that it con- 

 sists merely of common sulphate of lead, with a portion of pure 

 sulphur, varying from 6 to 10 per cent. 



2. The reading of Dr Knox's paper on the Natural His- 

 tory of the Salmon was concluded. 



The object of the author was a careful examination of facts in 

 the Natural History of the Salmon, which hitherto have been 

 taken merely upon opinion. He watched and carefully observed 

 personally the deposition of the ova or eggs of the salmon under 

 the gravel, — its long confinement in that situation, — its growth 

 into a fish about an inch in length, — its ascent through the 

 gravel, and rapid growth whilst in the rivers : the journals 

 of observation were partly read to the Society. Twenty weeks 

 was the period from the time of deposition to their bursting 

 the outer shell ; for nine days longer they continued under the 

 gravel as fishes, drawing their nourishment from the yolk of the 



