C 474 ) 
obferve, whether the Deprefllon did not continue at diifFcring 
times of the day, and found it to do fo, as well at night as at 
noon, though at this laft named time the Sun fhined hot upon the 
place and Veffels too. 
This Experiment was made, in all, four or five times,though not 
alwaies with equal, yet ftill with fome^ fuccefs, the Mercury in 
the feal'd leg ot the Gage being fometimes more and fometimes lefs^ 
but alwaies manifeftlydepreft ; which Phaenomenon was confirm- 
ed by the Obfervation we more than once made of the fudden re- 
turnof theQuickfilver to it former ftation, upon the unftopping 
of the Glafs, to give free admiflion to the outward Air. . 
Exp^i^^^t- the Eigh th^ 
Confidering,whilftI wasaboutthefeTryals, that Spirit of Vi- 
negar^ thoughin working upon Coral and fome other Bodies it 
not only produces ftore of bubbles, but alfo, as I have elfewhere 
deliver'd ^,a fomewhat odd kind of Ela- 
^ To the bettet under- ftical Subftance,yet being put upon Mi- 
fVandingof this the enfuing ^y^^ jf ^^^^ Qbfervation, tO 
Tryal may much conducejand , , , j -11 ^ j. • 
therefore is tranfcribed out work Calmly and Without producing 
of another paper, to which it froath;! thought fit to make tryal,whethcr 
properly bcloi^gs. ^^^^^ fj,^^^ folution of Mimnm 
would be accompanied with a permanent 
whofe bottpm was covered change of the Airs Spring; The Event I 
with beaten Coral, fome^Spi- ^^^^ f ^ j . 
rit of Vinegar was poured in, '^^^» 
and then the Glafs ftopple, 
which was very well ground, clofing the neck exaftly, weobfervcd, thatupon tlie 
working of the Menftruum on the Coral, ftore of bubbles were for a good while 
produced, which fucceffively broke in the cavity of the VefiTel, and their acceffion 
fo conflipatcd the Air, that theycomprefl: the Air imprifon'd in the clofed leg 
of the Gage three marks or Divifions, which IguefTed toaraount to about the third 
part of the extent it had before; But fome hours after the Corrofion had ccafed, 
the Compreflion made by this newly generated Air grew manifeftly fainter, and 
the imprifon'd Gage-Air drove down the Mercury again 'till 'twas depreft within 
ont divifion of its firft nation ; and thereabouts, or little lower, continued five 
or fix dayesj fo that in this operation there feemed to have been a double Com- 
preffive Power exercifed ; the one tranfientj by the brisk agitation of Vapours or 
Exhalations, zv\(\ the oxhtr durable y fromrhe Aerial and Springy Particles, either 
produced or extricated by the adion of the Spirit of Vinegar upon the Co- 
ral. 
A pretty quantity of .5/^/r/> of T/^^^^y being put upon Mi- 
nium in a Conical Glafs, furniflied with a Glafs ftopple and a Mer- 
cuiTial Gage, continued divers dayes without any fenfible Depref- 
fio.n of the Mercury in either leg, nor did any change appear in 
the 
