i ,; (2 3 7) 
be pretended, that a fuga vasui, or a Funiculus , is the caufe of 
the changes, we obferve. 2. It fhews 3 that not only the Air has 
weighty but a more confiderable one, than fome Learned iften; 
who will allow me to have prov’d 3 it has fome weight , will 
admit ; fince even the variation of weight in fo fmall a quantity 
of Air, as is but equal in bulk to an Orange , is manifestly di s- 
coverable uponTuch Bailanccs, as are none of the niceft. 3. Tin's 
Statical Barofcope will oftentimes be more parable, than the 
other : For many will finde it more eafie.to procure a good 
pair of Gold-fcales, and aBuble or two, than a long Cane, 
feal’d, a quantity of §ujc\ fiver, and ail the other requifits of 
the Mercurial Barofcope ; efpecially if we comprife the trouble 
and skill, that is requifite to free the deferted part of the Tube 
from Air* 4; And whereas the difficulty of removing the Mer- 
curial Inftrument has kept men from fo much as attempting to 
do it j even toneighbouring places ; the Effential parts of- the 
*SW£>Barofcope (for the Frame is none of them) may very 
eafily in a little room be carried, whither one will , without the 
hazard of being fpoifd or injur’d, y. There is not in Statical 
Barofeopes, as in the other, a danger of uncertainty , as to the 
goodncfs of the Inftruments , by reafon, that in the/e the Air is 3 
in fome more, and in fomelefs perfectly excluded 5 whereas in* 
thofe 9 that confideration has no place. (And by the way, I have 
fometimes,, upon this account 3 been able to difcover by our 
new Barofcope, that an efteem'd Mercurial one, to which I com- 
pared it, was not well freed from Air.) 6 . It being,as I former- 
ly intimated, very poffible to difcover Hydroflatically , both the 
bignefs of the Buble, and the Contents of the cavity, and the 
weight and dimenfions of the Glaffie fubftance ( which toge- 
ther with the included Air make up the Buble,) much may be 
difeover’d by this Inftrument, as to the height of the Air, at fb- 
lute or refpeUive. For 3 when the Mercury in the Mercurial Ba- 
rofcope is either very high, or very low , or af a middle ftation 
between its greateft and leaft height* bringing the dWir-Baro- 
tneter toanlxa dc Equilibrium^ (j with very minute divifions-; 
©faGraine, ) you may , by watchfully obfejrving , when the 
Mercury is rifen or fain juft an inch, or a fourth, or half an inch’ 
&c. and putting in the like minute divifions of a Grain to the 
lighter Scale y till you have again brought the Ballance to an 
exquifita* 
