Proceedings of the Royal Society of Edinburgh. 397 



Becquerel, and Pouillct, including some experiments on antimony 

 and bismuth, made at the author's request by Mr Harris, he con- 

 cludes, that the arrangement of the metals, as conductors of elec- 

 tricity, is the following, which he observes is probably better esta- 

 blished than the corresponding one for heat : — Silver, Copper, 

 Gold, Zinc, Brass, Iron, Plalininn, Tin^ Lendt Antimony, and 

 Bismuth. He observes, that the deviations from a common ar- 

 rangement only occur, where it is agreed by experiments on both 

 points, that the metals are extremely closely allied ; as, for exam- 

 ple, (jold and Silver, Iron and Platinum. His general conclusion 

 is this ; That the arrangement of conductors of heat does not differ 

 more from that of conductors of electricity, than either arrangement 

 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^ 

 has commenced. 



Jan. 21. — Dr Hope, Vice-President, in the Chair. The 

 following communications were 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 not a new atomic compound, but that it con- 

 sists merely of common galena, with a portion of pure sulphur, 

 varying from 6 to 10 per cent. 



% The reading of Dr Knox's paper on the Natural Histo- 

 ry 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 yoke of the 



