( 1788 ) 
Gauge at about 6 inches height. The event of which wa^» 
That the Vibrations were then not above inch largei o^ 
each fide, than in the Receiver iinexhauikd : and the Time 
loft, but about half a fecond in an hour , or ^ at moft. 
And fo, according as the Mercurial Gauge v/as more or lefs 
-high, I always found the Vibrations greater or Iciicr^ they 
gradually decreafing, according to the quantity at Air re- 
admitted- 
Having thus given an account of wh:u I experimented, 
with all the Variety which I thought neccflary, and with 
all the care I could, I fhall tor a Conclufion make fomc Re- 
marks, andf draw fome Inferences from what hath been fa.id. 
. I. What Mr Poyl l©ng Gnce obferved (from a Cock'd 
Piftol going down as fiercely in his Vacuum, as in the Air^ 
may be hereby farther confirmed, viz. That the Air is 
nottheCaufe ot the Motion of Reftitution in Solid Bodies, 
as Springs. For if it was, it would certainly have been dil- 
covered in fo tender an Inftjument as a well ad jufted Pocket- 
W^atch, lying under the perpetual Influence of two Springs. 
2. A» m VacHo (where the preffure of the Atmofphere is 
taken oflf) Heavy Bodies defcend quicker than they do in the 
open Air; So it may be obfervtd, That^Pendulums move 
fwifter in the Receiver exhaufted, than in it unexhaufted. 
That Heavy Bodies defcend quicker in Vaaio^ is evident 
from the fwift Defcent of the Icfs heavy Bodies, stsCork^ the 
D^?vpn ofSovpthijiles^ the I ghteji Feaiker,&c. which do all pre- 
cipirantly defcend, like a Scone, in a tall exhaufted Receiver^! 
And that the Pend^hm, in our Experiment, moved fa ftec^i 
in Vacne^ is raanifefl from its vibrating but two feconds in 
an hour flower, when the Vibrations were ^ ofan inchona 
fide,enlarged by thehigheft Rarefadion of the Air. Whereas 
I find by ci.periment,that near the fame encreafe of the Vibra- 
tions, dorb^ in theopen Air, make the Pendulum go 6or more 
fecondb flower in an hour, I hy. mar the fme ^fjcreafe^ be- 
caufe it is fcarce poffible to raptfage the Pallets fo, as nicely 
to make the fame Vibrations d^s were Vacuo. 
3. The 
