feerned far fmaller Alterations of the Weight of thcAir^fiace 
I had the pleafure to fee the Buble fometimes in an (zquiUbrium 
with the counterpoife^ fometimeSj when the Atmofphere was 
high, preponderate fo manifeftly, that the Scales being gently 
ftirr'd, the Cock would play altogether on that fide , at which 
the Buble was hung / and at other times (when the Air wa,s hea- 
vier) that, which was at the firft but the Counterpoife ^ would 
preponderate, and, upon the motion of the Ballance, make the 
Cock vibrate altogether ©n its fide. And this would con- 
tinue fometimes many daics together, if the Air folong re- 
tained the fame meafure of gravity ^ and then (upon other chan- 
ges)the Buble would regain an aquilibrium.ov a preponderance; 
fo that I had oftentimes the fatisfadiion, by looking firft upon 
the Statical Barofcope (as for diftin<3:ions fake it may be calFd J 
to foretell ^ whether in the Mercurial Barofcope the Liquor 
were high or low. Which Obfervations though they hold as 
well in Winter, and feveral times in Summer ( for I was often 
abfent during that feafon) as the Spring, yet the frequency of 
their Viciffitudes (which perhaps was but accidental) made 
them more pleafantin the latter of thefefeafons. 
So that, the matter of FacS: having been made out by variety 
of repeated Obfervations, and by fometimes comparing feve- 
rail of thofe new BarefeopBs togetherj I fliall add fome of thofe 
Notes about this Inftrument, which readily occur to my aie- 
mory^referving the reft till another opportunity. 
And Ftrft, if the ground, on which I went in framing this Ba^ 
fofcQpe^ be demanded, theanfwer in fliort may be"i i. That, 
though the Glafs-buble, and the Glafs-couaterpoife^ at the 
time of their firft being weigh*d,be in the Air, wherein they both 
are weigh'd, exadly of the fame weight ; yet they are nothing 
near of the fame bulk 5 the Bublcj by reafon of its capacious 
cavity ( which contains nothing but Air, or fomething that 
weighs lefs than Air ) being perhaps a hundred or two hundred 
times ( for I hai^e not conveniency to meafure them ) bigger 
than the Metalline counterpoife. a. That according to a 
Hydrojlatical Law ( which you know I have lately had occafion 
to make cut) If two Bodies of equal gravity, but unequal bulk 
come to be weighed in another Medium^ they will be no longer 
, li 2 ^ equi- 
