JOURNAL 



O F 



NATURAL PHILOSOPHY, CHEMISTRY, 



AND 



THE ARTS. 



JUGUST, 1801. 



ARTICLE I. 



jt Letter ftom TaoMAS YouKGt M. D. F. R. S. ProfeJ/or of Natural Philofiphy in the Royal 

 Injlitution, refpeSling Sound and Light, and in Reply to fame Obfervations of Profeffor 

 RoBiSON' 



To Mr. NICHOLSON. 

 SIR, 



J-N the fupplement of the Encyclopsedia Britannica, are inferted feveral excellent articles 

 by Profeflbr Robifon of Edinburgh : one of them appears to require fome public notice on 

 my part, and I confider your valuable Journal aS the moft eligible channel for fuch a com- 

 munication, efpecially as you have lately done me the honour of reprinting the paper 

 which gave rife to the Profeflbr's animadverfions. But in the firft place, I ftiall beg leave 

 to recall the attention of your readers, by a fummary enumeration, to the principal pofitions 

 which I have in that paper endeavoured to eftabllfli. 



I. Sound, as tranfmitted through the atmofphere, confifts in an undulatory motion of 

 the particles of the air, Seft. III. This is generally admitted ; but as the contrary has even 

 very lately been aflerted, it is not fuperfluous to have decifive evidence of the hO:. Pro- 

 feflbr Robifon's experiment vcith the ftop-cock furniflies an argument nearly firailar. 



Vol. V. — August 1801. . Y 2. A 



