446 



in an aquatic animal, nor entirely remove the effect of the chain of 

 bones and column of air within the tjTupanum. The autlior shewed, 

 that in two, at least, of the three malformed individuals, the case was 

 different, as circumstances existed which obstructed the secondary 

 action both of the chain of bones and tpnpanic column of air, so that 

 these two individuals might be regarded as hearing solely through 

 the solid parts of the head. In these two individuals it was ascer- 

 tained, by accurate and frequently-repeated experiments, that hear- 

 ing was not, as in other j^ersons, most perfect near the site of the 

 ear, but on the top of the head ; and this was the case whether the 

 sounds proceeded from a body held in contact with the head, or at 

 some distance in the air. So exclusively, indeed, did the hearing 

 seem to take place in these two indi\'iduals tlirough the hard parts 

 of the head, that neither, but particularly one of them, seemed ever 

 to have referred sounds to the ear as the seat of the sensation of 

 hearing. As might be supposed in such circumstances, these persons 

 made no distinction between hearing in one ear and in the other ; 

 and could obtain, therefore, no knowledge of the direction of sounds 

 in the same manner as other people do, by the comparison of the 

 relative intensity of sounds in the two ears, or in the same ear in 

 difl'erent positions. The autlior made some remarks on the amount 

 of deafness which is calculated to induce dmubness, as well as upon 

 the means of distinguishing different kinds of deafness, and the dif- 

 ferent means that ought to be employed for their relief. He con- 

 cluded his paper with some remarks upon the subjectof double hearing, 

 considered with reference to the obvious impossibility, in the indi- 

 viduals referred to, of the sensations of one ear being distinguished 

 from those of the other, in consequence of the perfectly equal and 

 simidtaneous communication of sonorous vibrations to both ears. 



2. On the Luniinousness of the Sea. By Dr Traill. 



The author stated, that this phenomenon seems scarcely to be 

 noticed in the writings of Aristotle or of Pliny which have reached 

 us, though Pliny was familiar with the light emitted by certain 

 shell-fish, and by the Sea Lung or Medusa. 



j\Ir Boyle gives an account, from the journal of a shipmaster, of 

 the lumiaousness of the sea ; and it is particidarly detailed, from per- 

 sonal observation, in the Indian voyage of Father Bourzes, in 1704. 



The first philosophers, who ascribed it to light emitted by living 

 animals, would seem to be the Abbe XoUet, Professor VianeUi, and 

 Dr Gressellini of Venice, about the middle of the last century. In 

 Cook's first voyage, the luminous properties of several marine ani- 



