17G Proceedings of Societies. 



compound nature. The author concludes his paper by showing how in 

 all probability other elements might actually be considered as compounds, 

 referring particularly to selenium and tellurium, chlorine, iodine, and 

 bromine, and the metallic bases of the alkaline earths and alkalies. 



Monday, Dec. 18, 1854. Right Rev. Bishop Terrot, V.P., in the Chair. 



Miscellaneous Observations on the Salmonidce. By John Davy, 

 M.D., F.R.S., Inspector- General of Army Hospitals. 



These observations are given in seven sections. 



In the 1st, the author treats of the air-bladder of these fish, and the 

 contained air, which he found, in every instance that he examined it, to be 

 chiefly azote. 



In the 2d, he points out a mistake he had fallen into in the instance of 

 the female fish, as regards its abdominal aperture, which in a former paper 

 he had described as open only for the passage of the ova ; on further ex- 

 amination made on the larger species, he has ascertained, that though 

 virtually closed, except during the spawning time, it is not absolutely 

 either by a membrane or adhesion. 



In the 3d, on the breeding localities of the Salmonidae, he states his opi- 

 nion that running water is not essential to the hatching of the ova, and 

 he adduces instances in proof and illustration. 



In the 4th, which is on the variable time of the hatching of the ova, he 

 describes examples of difference as to time of the production of the young 

 fish under circumstances apparently identical, or circumstances only very 

 slightly different, tending to show the influence of a vis insita in the 

 several ova. 



In the 5th, on circumstances and agencies likely to take effect on the 

 young fish, he notices two trials, — one in keeping the young fish in dark- 

 ness after quitting the egg, which had no marked influence ; the other in 

 keeping them in the smallest portion of watir capable of covering them, in 

 relation to the position of young fish during a time of drought ; in one 

 instance life was protracted 52 hours ; in another 74. 



In the 6th, on the food of the young fish, he endeavours to prove that 

 the food most suitable for them, and for which they are best fitted, is the 

 infusoria. Young charr, under his observation, attained their perfect 

 form and became fit to be set at large, to which no food had been given, 

 and were, it is presumed, fed and nourished by these microscopic animal- 

 cules. 



In the last section he submits some remarks on the vexed question of 

 the par, viewed as a species, and comes to the conclusion that till a par 

 is found propagating its kind, proof must be held to be wanting of the 

 existence of such a fish, a true species distinct from the salmon or sea- 

 trout fry. 



On the Structural Character of Rocks. Part III., Remarks on the Stra- 

 tified Traps of the neighbourhood of Edinburgh. By Dr Fleming. 



The author referred in the first instance to the character of Stratifi- 

 cation, illustrating the subject by specimens displaying the intermittent 

 character of the carrying agent, and of the supply of material, pointing 

 out the Hailes Quarry as furnishing the best example of the repetitions 

 of strata. He then stated the views of Townson, \V nitehurst, and Jame- 

 son, as to the relation of the trap rocks to the sandstones with which they 

 are interstratified. He then took notice of a statement in the thirteenth 



