. ( ipoj ) 
two Atmofpheres being Impeird, and the Bell made to 
Ring, a notable Improvement of the Sound was then ma- 
nifeft- But upon the Intrufion of the ijd, 4th and 5th 
Atmofpheres^ the Bell being made to ftrike, the Sound 
feem'd not to be Propagated proportlonably to the firfl and 
fecond 5 which might happen by means of forne Efcapes 
of Air, or, which is much to the fame purpofe, the Valve, 
which fhould have hindred the Return of the Injeded 
Air, did not hold fo tight as I expedted, or as it ought ^ 
but that feme of the Intruded Air w^onld repafs into the 
S)'fhon, by which means the Quantities fappos'd Injedted 
were deficient. Another reafon the latter Atmofpheres 
did not propagate the Sound as the two firft, is this, altho 
25 Compreffions of the Sjphon Qve equal to the Natural 
Content of the Recipient,yet when the Air becomes pretty 
flrongly Condens'd, as by the fntrudon of 4 or 5 Atmof- 
pheres. the remaining Air at every ft roke which will lye be- 
twe-eathe Bottom of the Emholm and the yalve (aitho but 
rittle)isat th€ fame Denfity at the fame time as the Air in the 
Recipient^ which,upon drawing op the forces^will extend 
it felfto fupply fuch a fpace of the Cylinder as fo much com-* 
men Air f and is fo much (liort of what fliould be In)eded 
at every ftroke, 25 of which become equal to the Natu- 
ral Content-of the Receiver. Hence the Deficiencies of 
the Real Atmofpheres or Quantities, by a certain number 
of Strokes may be very confiderabie, and to acc<?unc for 
them mo{V> difficulty and fo [ muft leave them for the 
prefent, begging pardon lor this digreflicn. I conclude^ 
NotwithfiraridingtheDeficiencies are not known, yet at the 
end of the 5 (tho fmperfedt) Atmofpheres, the Bell being 
fliaken as at firft, it was the Opinion of a Gentleman then 
50 yards diftant, that the Sound fcem'd to be aknoft as 
and asfenfibie as when it came to be made and ex- 
posd iivthe open Air. 
Jt/nethe 9th, about 5 in the morning I repeated thk 
Experiment in an open field, knov^^n by the uame of 
th. 
