Intelligence and Miscellaneous Articles. 235 



mainly characterized by the union of certain sections of the series 

 into natural groups. A, B, C, &c., and by the establishment of a di- 

 stinct middle Silurian stage, and an equally distant middle Devonian 

 stage. The lithological and iialaeontological characters of the several 

 groups of strata are then treated of in succession ; their resem- 

 blances and differences, in these respects, being carefully noted. 

 From the consideration of the stratigraphical details contained in 

 this and the preceding paper. Dr. Bigsby deduces two main conclu- 

 sions, namely, 1. That from the Potsdam sandstone to the summit of 

 the Carboniferous rocks, these strata were laid down in comparative 

 quiet ; subject to occasional, vertical, variable, secular oscillations, 

 ■which led to considerable superficial changes. 2. That their eleva- 

 tion, foldings, fractures, and metamorphism were effected after the 

 deposition of the whole, and in a single prolonged transaction, prin- 

 cipally in a N.E. and N.W. direction, along the present Appalachian 

 ridges and their continuation from Labrador to near the Gulf of 

 Mexico. The evidences on which these two propositions rest were 

 next detailed ; and the views of the Professors Rogers on these 

 points, and the author's objections, were stated in full. 



XXX. Intelligence and Miscellaneous Articles. 



ON THE INFLUENCE OF MUSICAL SOUNDS ON THE FLAME OF A 

 JET OF COAL-GAS. BY JOHN LECONTE, M.D. 



A SHORT time after reading Prof. John Tyndall's excellent article 

 " On the Sounds produced by the Combustion of Gases in 

 Tubes*," I happened to be one of a party of eight persons assembled 

 after tea for the j)urpose of enjoying a private musical entertainment. 

 Three instruments were employed in the performance of several of the 

 grand trios of Beethoven, namely, the piano, violin, and violoncello. 

 Two 'fish-tail ' gas-burners projected from the brick wall near the 

 piano. Both of them burnt with remarkable steadiness, the windows 

 being closed and the air of the room being very calm. Nevertheless 

 it was evident that one of them was under a pressure nearly suffi- 

 cient to make \tjlare. 



Soon after the music commenced, I observed that the flame of the 

 last-mentioned burner exhibited pulsations in height which were 

 exactly synchronous with the audible beats. This phsenomenon was 

 very striking to every one in the room, and especially so when the 

 strong notes of the violoncello came in. It was exceedingly inter- 

 esting to observe how perfectly even the trills of this instrument 

 were reflected on the sheet of flame. A deaf man might have seen 

 the harmony. As the evening advanced, and the diminished con- 

 Buraption of gas in the ctiy increased the pressure, the phenomenon 

 became mere conspicuous. The jumping of the flame gradually in- 

 creased, became somewhat irregular, and finally it began to flare 

 continuously, emitting the characteristic sound indicating tlie escape 

 of a greater amount of gas than could be properly consumed. I then 

 ascertained by experiment, that the phaenomenon did not take place 



* Phil. Mag. S. 4. vol. -xiii. p. 473, 1857. 



