(237) 
be pretended^ that a fuga vami, or a Funiculus ^ ss the caufe of 
the changes, we obfcrve. 2, It lliews^ that not only the Air has 
weighty but a more confiderable one, than fomc Learned men, 
who will allow me to have prov'd 3 it has feme weight , will 
admit ; fioce even the variation of weight in fo fmall a quantity 
of Air, as is but equal in bulk to an Orange ^ is manifeitly dif-^ 
coverable uponfuch Ballances, as are none of the niceft. 3. This 
Statical Barofcope will oftentimes be more parable 5 than the 
other : For many will finde it more cafie.to procure a good 
pair of Gold-fcales, and aBuble or two, than a long Cane 
feal'd, a quantity of and all the other reqmfus of 
the M^rw/^/Barofcope 5 efpecially if we comprife the trouble 
and skill, that is requifite to free the deferted part of the Tube 
from Air> ^> And whereas the difficulty of removing the Met- 
^r/^rf^i/Inftrument has kept men from lo much asattemptiDg to 
do it, even toxieighbouriog places 5 the EfTentia! parrs ot the 
iS^^^/^-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 fpoii'd or injur'd. j. There is not in Statical 
Barofcopes, asm the other, a danger of uncertainty, as to thq 
goodncfs of the Iiiftruments 3 by reafon, that in thefe the Air isj 
in fome more, and in fomelefs perfedlly excluded 3 whereas ia 
thofe^ that confideration has noplace, (And by the way J hive 
foraetimesj upon this account J been able to difcover by our 
new BarofcopCj that an cfteem*d Mercurial one,to which I com- 
pared ir,was not well freed from Air.) 6. It being^asl former- 
ly intimated, very poffible to difcover f7)'^ro/?^^/Va//y 5 both the 
bignefsof theBuble3and the Contents of the cavity, and the 
weight and dimenfions of the Glaffie fubftance ( which toge- 
ther with the included Air make up tlieBuble,) much m?.y be 
difcover'd by this Inftrument, as to the Weight of the hiwM'C^' 
lute or refpeBive, Forjwhen the ^uifi^JIlver in the Mercurial Ba- 
rofcope is either very high, or very low , or at a middle ftarion 
between its greateftand leaft height^ bringing the Scale-EMO- 
meter to ^m'R^^iSt jEquilibrium'-i (iwith very minute divifions 
of aGraine, ) you may^ by watchfully obferving , when the 
Mercury is rifen or fain juft an inch, or a fourth, or half an inch 
^c. and plotting in the like minute divifions of a Grain to the 
lighter Scale 3 till you have again brought the Ballance to nn 
' cxqiiiiue 
