J22 EFFECTS OF THUNDER. 



VII. 



tetter from a Correfpondent on the Efftdis of Thunder onfermenU 

 ing Liquids; the Chemical A6iion of Sound, and Tremulous , 

 Motiom, xvith otlwr Obfervations, 



NexLcajlle, Dec, 16, 1803. 



To Mr. NICHOLSON. 

 SIR, 



l^ONVERSATION is certainly one of the moft defirable 

 means for the increafe and diffemination of knowledge, what- 

 ever defcription it may be of, and if the following remarks, 

 urifing from an accidental convcrfation with a fcientific friend, 

 be not altogether unworthy of your notice, you may make 

 what ufeof them you think proper; and if thought worthy of 

 being prefented to the public, you are at liberty to make any 

 iiecelTary alteration in the flile that will render them more wor- 

 thy of the honour I folicit. 

 Changes pro- ^^ ^^^ h^QVi obferved, fo often indeed,' that it has almoft be- 



riuccd in beer conae a popular remark, that the noife of thunder produces a 

 thunder^^*'" fiirprifing change on beer, and on cream; the firft becoming 

 four, and the latl rancid, when they are agitated by this extra- 

 Suppofed pre- Ordinary found. It has alfo been obferved, I believe, that the 

 ventative re- effects of thunder on malt liquors maybe prevented by laying 

 ^^'^^)* a cord over the calk, at each end of which, a flone, or other 



hard and ponderous fubftance is fufpended and kept in contact 

 with theoutfide of the veflel containing the liquid liable to be 

 affedcd by this kind of noife. 

 The efFea fup. Now we may be able to form forae judgment of the manner 

 poied to arife in which thefe liquids are afiefled, by attending to the tremu- 

 1^11^°^"°"'' lous motion produced on thofe glafles called linging and mufi- 

 . calglafTes, when the furface of the firft is agitated by the breath; 

 ^ and the liquid in the laft by the vibration produced by the finger 



drawn along the rim of the glafs, which varies in its tone in 

 proportion to the quantity of liquid it contains. In the courfe> 

 of the tone or found, if the glafs be prefled with the finger, the 

 found either ceafes or is confiderably diminithed, and upon ap-r 

 plication of the finger at the commencement of the found it 

 will be evidently felt that both the glafs and the liquid are in a 

 Hate of agitation, and that this agitation ceafes or flops when 

 the agitated body is touched by anpther in a quiefcent Hate. 



Thil 



