( 51^9 ) 
$* (Which is equivalent, but more eafily admioiftrecf^ ) 
Whether if fuch a Tube, fo fiUcdj be at firft fo ioclioed (as 
GF) that its height above AB be lefi than 29 loches y may 
not be Icifurely and gently eredJ'ed, fo as to remain full, not 
only to the height of I, but of G or D > 
6. Whether cleaned Quickfilver will, in the open Air^ 
run in a Siphon higher that 29 Inches ? 
7* If not in the Air, whether it will fo run, if the lower 
Leg open into well- cleanftd Water ? 
8* (Which I do principally recommend^) In a Tube (b 
filled with cleanfcd Quickfilver, as to (tand top-full at a 
greater height than the ufiial Standard, as GD; in cafe 
?ome part be forced out 5 not by admifiion of Air but by 
Jogging the Tube, ( I fuppofe as much as HD,) and a flop 
then made : Whether the reft CH (at a greater height than 
Ij the ufual Standard,) may be made fo to ftand of it felf, 
Dotwithftanding the voidance of H D? For by this Ex- 
periment alone, if it fucceed, it will appear, that it is not 
onely want of room for the Subtile matter to recolledl it 
felf, which hinders the (iifpcnded Quickfilver from falliog 5 
but rather (unlefi (bme probable caufe can be found,) the 
want of a Spring to put it in motion. If it will not fucceed^ 
I (hould rather thii^k , the Springy Air doth make its way 
through the Quickfilver than through the Clafs. 
9. Whether cleanfed Quickfilver will remain fufpended 
in an inverted Tube ( at leaft a (hort one , and with a fmall 
Orifice, ) though its Orifice C be no immerg'd in Qiiick- 
filver, but either in the open Aifj or at leaft in Water ? 
10^ If fo 5 then whether it will do the like , if^ a little 
being forced out, there be fome void room left at the Tops 
atHD> 
Thefc are nice Experiments, and of fome difficultys 
but if carefully adminiftred 5 may be of good ufe in our 
fearch after the true nature of Gravity: Which may poffi- 
bly have a greater connexion with the Spring of the Air, 
than men arc aware of ^ fince on the prefence or abfcnce 
thereof doth mainly depend the falling or not falling of 
Bodies 
