Along the ſide of this Tube was paſt
ed a ſtraight narrow piece of Parchment,
divided into twenty ſix equal parts, mark
ed with black Lines and Figures, that by
them might be meaſur'd both the inclu
ded Air and its dilatation. Afterwards
we fill'd the Tube with Water almoſt to
the top, and ſtopping the open end with
a Finger, and inverting the Tube, the
Air was permitted to aſcend to the above
mention'd Glaſs bubble. And by rea
ſon this aſcent was very ſlow, it gave us
the opportunity to mark how much more
or leſs then one of the twenty ſix diviſi
ons this Air took up. By this means, af
ter a tryal or two, we were inabled to con
vey to the top of the Glaſs a bubble of
Air equal enough, as to ſight, to one
of thoſe Diviſions: Then the open end
of the Tube being put into a ſmall Viol,
whoſe bottom was cover'd with Water
about half an Inch high; we included
both Glaſſes into a ſmall and ſlender Re
ceiver, and cauſed the Pump to be ſet a
work. The event was, That at the firſt
exſuction of the Air there appear'd not
any expanſion of the bubble, comparable
to what appear'd at the ſecond, and that
upon a very few exſuctions the bubble
ed a ſtraight narrow piece of Parchment,
divided into twenty ſix equal parts, mark
ed with black Lines and Figures, that by
them might be meaſur'd both the inclu
ded Air and its dilatation. Afterwards
we fill'd the Tube with Water almoſt to
the top, and ſtopping the open end with
a Finger, and inverting the Tube, the
Air was permitted to aſcend to the above
mention'd Glaſs bubble. And by rea
ſon this aſcent was very ſlow, it gave us
the opportunity to mark how much more
or leſs then one of the twenty ſix diviſi
ons this Air took up. By this means, af
ter a tryal or two, we were inabled to con
vey to the top of the Glaſs a bubble of
Air equal enough, as to ſight, to one
of thoſe Diviſions: Then the open end
of the Tube being put into a ſmall Viol,
whoſe bottom was cover'd with Water
about half an Inch high; we included
both Glaſſes into a ſmall and ſlender Re
ceiver, and cauſed the Pump to be ſet a
work. The event was, That at the firſt
exſuction of the Air there appear'd not
any expanſion of the bubble, comparable
to what appear'd at the ſecond, and that
upon a very few exſuctions the bubble