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between mercury on the one hand, and various saline and acid fluids 
forming parts of active voltaic circles on the other. He also described 
and showed to the Society the undulatory motions which he had ob- 
served in mercury, when forming the cathode of a constant voltaic 
current in solutions of chloride of sodium, containing small quantities 
of sulphuric acid. 
2. On the Natural History of the Herring. By J. M. 
Mitchell, Esq. Communicated by Dr Allman. 
Before entering on the details of the natural history of the herring, 
the author points out the great value of the herring-fishery to the 
maritime nations of Europe ; and quotes various scientific authorities 
to show, that the herring is superior in economical importance to 
every other fish. Thus Cuvier, in his work on fishes, edited by Pro- 
fessor Valenciennes, says, — “ Les grands politiques, les plus habiles 
economistes ont vu dans la peche du hareng la plus importante des 
expeditions maritimes.” 
Such views have led the British, Dutch, Swedish, and Norwegian 
governments, to inquire at present into the natural history, and to 
legislate regarding the fishery of the herring. The author has de- 
scribed the principal steps taken by these nations, and has given im- 
portant statistical details of the British herring fishery, showing, 
that fish, to the value of upwards of a million sterling are annually 
taken on our coasts. 
The high value of the fishery, not only in promoting the welfare 
of a large portion of our population, but in producing a strong, hardy, 
and industrious race of fishermen, most valuable to such a maritime 
nation as Britain, is next referred to. 
The author then points out various errors regarding the herring 
which have been committed in works of high authority, such as 
Cuvier’s work on fishes, already referred to, M‘Culloch’s Dictionary 
of Commerce, and the last edition of the Encyclopaedia Britannica. 
He conceives that he has solved the doubtful questions, regarding the 
natural history of the herring, — an object of the greatest importance, 
when we consider the high economical value of the fishery. He also 
points out several new and important facts regarding the appearance 
of the fish on our coasts. Among others, that the herring swims 
