Led. VII | Salts in Wave: , 
ata 
393 

CRP ALP, “FEE 
Wherein, from the Experiments in the forevoing Chapte#, 
is fhewed, the Caufe of the Motion of the Mercury in 
the BAROMETER. 
LoS 


@j, OR the doing of this, it will firlt be acknowlede’d, 
“4 That not only feveral forts of Suiphur, but alfo of 
~ Volatile Salts, are continually fublimed from moft 
Bodies into the Aer, So Lightning, from the celeri- 
ty ofthe accenfion, appears to be made ofa Meteor, 
which is Notro-Sulphureons, Snow dependeth upon 
LG a Mixture of Nitrous, and other salts s as is evi- 
ent, from the regularly and differently Figur'd Parts, which compofe 
the whole Body of a Szomy Cloud, before it clufters into Flekes. And 
one reafon, why Raiz is the beft Water for any Soyl, is becaufe it is im- 
pregnated with divers Volatile and Fruitful salts. And fo from other 
Meteors. 

2. §. And-next, that thefe Salts, are not always in the fame Quan- 
tity, Proportion, and State, in the Aer : but that fometimes they are 
more copious 3 at others, lef$: fometimes, one more copious, than an 
other: fometimes, more plentifully diffolved 5 at others, more fpare- 
ingly: and that, either as they are more or lefs pure and diffoluble; or 
according to the quantity of the Vaporous Parts in the Aer, in which 
they are incorporated or diffolved. 
3. §. Thus much being granted, from the Experiments in the fore- 
going Chapter compared together, we may refolve our felves about 
fome Phenomena in the Barometre. Which {eems to vary, not fo much 
with the meer Weight of the Aer, which hitherto hath been fuppo- 
fed: as by the different preflure it makes, in being cromded more at 
one time, than at another. That is, according as certain Nitrous, or 
other Saline Bodies, take up lefS space in the Aer, when diffolved in the 
Watery Parts therein, than while they are undiffolved. 
4. §. And therefore it is efpecially to be obferved, That as the 
Mercury commonly rifeth in the Cylinder for fome days, but always 
for fome time, before the change of the Weather, whether for sow or 
Raiz : So, that then it prefently falleth again, even before the Sow 
or Rain falls. Whereas, if the Weight of the Aer, were the only, or 
the chief Caufé ‘of the afcent of the Mercury 5 than asit rifeth all the 
while the Weather is gathering, fo it would keep its ftanding or heighth, 
until the Weather breaks and falleth down: which yet it never doth, 
but always falls before it ; fometimies no lefs than a whole day. The 
Canfe whereof is, in that all the while the Mercury rifeth in the Cyhin- 
der, the Aer is cromded with more and more Salize Parts, which by 
the 















































