THE 



LONDON and EDINBURGH 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



♦ — 



[THIRD SERIES.] 

 NOVEMBER 1833. 



LIV. On the Vibration of heated Metals. By Arthur Trk- 

 velyan, Esq. ; including a Letter on the same Subject by 

 Dr. W. Knight.* 

 A S it is always interesting to know the accidental circum- 

 -*•*- stances which lead to the discovery of any new fact in 

 natural science, I shall begin by relating the manner in which 

 I was led to observe the vibrations of heated metals. On the 

 9th of February 1829, I was about to spread with a plaster- 

 iron some common pitch, when the iron being at too high a 

 temperature, I placed it in a slanting direction against a block 

 of lead, the handle resting on the table: shortly after doing so 

 I heard a shrill high tone, which much resembled a note pro- 

 duced on the chanter of the smaller Northumberland pipes, 

 an instrument played on by my father's gamekeeper. Not 

 knowing the cause of the sound, I thought he might be prac- 

 tising out of doors. The room being on the ground floor, I 

 went outside, when the sound was no longer heard; and seeing 

 no person, returned again to the room, when I was surprised 

 at still hearing the sound as shrill as before. After looking 

 about for a few minutes, I at last approached closer to the 

 iron, perceived the vibration, and thence found the imme- 

 diate cause of the sound. I was much surprised and pleased ; 

 but at that time, not having studied any branch of natural 

 philosophy connected with the subject of heat, I was not aware 

 that it was a fact which had not been before observed (al- 

 though it struck me so at the time). I came to Edinburgh in 

 November 1830, and attended Dr. D. B. Reid's class of 



* Communicated by the Author. Part of this paper was read before the 

 Section of Physics of the British Association, meeting at Cambridge, Juii~ 

 27, 1833. 



Third Series. Vol. 3. No. 17. Nov. 1833. 2 T 



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