immediately after, another, and then a third, 
if you look very attentively, you will peiv 
ceive, that their refpeftive circles will pro-r 
ceed without interruption, and ftrike the 
fhore jn regular fucceffion, This experi- 
ment may be more fatisfactorily made, on 
your table, in a large trough of Quickfilver. 
If you ftrike the furface at one end, with 
your finger, and then immediately at the 
other, you will fee the waves of each run to 
the oppofite extremity of the trough, pafT- 
ing each other without producing any con- 
f ufion or interruption. This by way of il- 
luftrationj but furely the facl is a fufficient 
demonftration, that the atmofphere pofTefles 
the faculty of conveying founds in the moft 
rapid fucceffion, or combination, as dif- 
tin6Uy as they were produced. Jt pofleffes 
the power not only of receiving and pro- 
pagating fimple and compound vibrations 
in direct lines from the voice or inftrument; 
but of retaining and communicating founds 
with equal fidelity, after repeated reflections 
and reverberation, as you have often been 
convinced by the found of French-horns 
among the hills. I fhall purfue the fubjecT: 
in my next letter : till then, farewel. 
L E Tr 
