216 



MISCELLANEOUS INTELLIGENCE. 



MEDAL FOR CHEMICAL DISCOVERIES. 



John Fuller, Esq. has founded a gold medal of the value of ten 

 guineas, to be given to such members of the Royal Institution as 

 have distinguished themselves by their labours in chemical science. 

 He has liberally presented one of these medals to each of the fol- 

 lowing-individuals, viz. Sir H. Davy, Dr. Wollaston, Mr. Hatchett, 

 Mr. Brande, Mr. Faraday, Mr. Children, and Mr. F. Daniell ; and 

 proposes, in future, that one of these medals shall be presented bien- 

 nially. The dies are executed by Mr. Wyon, chief engraver in His 

 Majesty's Mint ; upon the obverse is the head of Francis Lord 

 Bacon ; and on the reverse an appropriate inscription, surrounded 

 by wreaths of palm and laurel. 



I. Mechanical Science. 



1 . Motion produced by the contact of different Substances. — The 

 following fact is one published as having been described by M. B. 

 Prevost, in 1814 : — If a very small drop of oil be placed upon a 

 large drop of mercury, it produces a greater or smaller extension 

 in the latter. This phenomenon, with other similar ones, is attributed 

 to a combination of the oil with the mercury, which produces a com- 

 pound, the molecular attraction of which is less strong than that of 

 pure mercury. — Bull, Univ. A. viii. 341. 



2. On a Difference in the Velocity of Intense and Feeble Sounds. 

 — [From a correspondent.] — In some interesting remarks upon 

 sound in the seventh number of the Edinburgh New Philosophical 

 Journal, Mr. Meikle has called in question the truth of the received 

 doctrine, that all sounds (whether loud or faint) move with the 

 same velocity. Although this is true in ordinary circumstances 

 when the sounds have not much intensity, (as when we listen to 

 distant music,) yet it may cease to be true with regard to the in- 

 tense report of a cannon. Indeed, as Mr. M. well observes, theory 

 would lead us to suppose that the enormous quantity of heat which 

 accompanies the explosion would increase the elasticity of the air, 

 and the velocity of the sound, much more than in the case of sounds 

 created by simple percussion. 



It is true that in this part of the world no such difference has been 

 observed, which may either arise from the comparison never having 

 been carefully made, or from the difference of velocity being really 

 inappreciable. In the frozen climates of the North, however, such 

 a difference, if it exists, may be expected to manifest itself; for in 

 an atmosphere perhaps a hundred degrees of Fahrenheit colder than 

 that in which European experiments have been made, the heat at 

 the mouth of the cannon is (relatively to the temperature of the 

 air) very greatly increased. Such I think is the conclusion of 



