370SCHOOL SCIBNCB AND MATHEMATICS
AN APPARATUS FOR BOTH BOYLE’S AND CHARLES’S LAW.
BY C. E. LINEBARGER,
Lake View High School, Chicago, III.
The apparatus consists of an open and a closed manometer,
both straight and vertical, and made of glass of ordinary size,
with their lower ends dipping into mercury contained in a.vessel
connected with an air compressor. To vary the temperature of
the air within the closed manometer, this may be surrounded
by a jacketing tube (not shown in the figure) through which
liquids at different temperatures or the vapors of boiling liquids,
such as water, ether, acetne,
carbon tetrachloride, alcohol,
etc., may be. passed.
The open manometer Is
about no cm. long and passes
through one of the holes of a
thrice perforated stopper.
The closed manometer is
about 60 cm. in length and
passes through a second hole,
while the third hole is pro-
vided with an L-tube. The
lower ends of the manometers
should be rotated in a flame
until they fuse nearly to-
-
gether, leaving an opening
about a millimeter in diam-
eter; this will prevent undue
surging of the mercury when
forced up into the tubes. The
upper end of the closed ma-
nometer should be as nearly
flat as it is possible to make it
so that no’ correction need be
applied to the volume (actu-
ally measured as a length on
the assumption that the bore
of the tube is uniform) on
account of the convexity of
the end. It is well to have the
upper end of the open ma-
, APPARATUS FOR BOYLB’S LAW 371
nometer flared out like a funnel, or fitted with a cork over which
is fixed a broken test tube, such an arrangement preventing the
overflow of mercury, which may otherwise happen should the air
in the vessel be compressed too rapidly.
The stopper is fitted to a screw cap bottle, and a circle punched
out of the cap just large enough to accommodate the three tubes.
To fill the closed manometer with dry air, connect it with a
chloride of calcium tube and pass a Bunsen flame along it until
its entire length is heated nearly to redness. Let it cool to the
temperature of the room, disconnect from the drying tube, and,
before any considerable amount of the’ dried air can escape, dip
the open end of the tube into vaseline. The short plug of vas-
eline that will enter the tube effectually seals the dried air unless
it is heated too much by handling.
Fill the bottle to a depth of about three centimeters with clean
and dry mercury, cover the mercury with a thick layer of cal-
cium chloride1, insert the stopper into the neck of the bottle,
and push the ends of the manometers down nearly to the bottom.
Screw on the cap and, connecting a bicycle valve and pump to
the L-tube by means of rubber tubing, pump air into the bottle
until the stopper is forced up snugly against the cap. It may
be found necessary to bind the rubber tubing by wire or string
both to* the L-tube and to the bicycle valve.
Remove the bicycle valve and pump and substitute an exhaust
pump. Close the upper end of the open tube with a tiny lump
of beeswax. Exhaust the air in’the bottle a little, and then dis-
connect ; the mercury will rise in the tubes. Continue the ex-
haustion by degrees until the mercury rises to a distance above
the stopper equal to about a fourth of the length of the closed
manometer. Replace the rubber tubing connecting the L-tube
to the bicycle valve, interposing a screw cock and binding the
rubber tubing to the valve and L-tube.
The jacketing tube is a piece of wide and thin glass tubing
with its ends flared a little for the reception of stoppers, and is
a little longer than the portion of the closed manometer extend-
ing above the screw cap. Its ends are closed with two-hole stop-
per’s, one hole of each of which is fitted with an L-tube, while
the closed manometer is thrust through the other hole of the
lower stopper, and a thermometer through the remaining hole of
the upper stopper.
^To prepare perfectly dry calcium chloride in thin cakes or plates, proceed as follows:
Heat a lump of the chloride held by crucible tongs in a large blast flame. The chloride^
will fuse and the drops that fall from the lump are cauarht upon a plate or a piece of sheet
metal.
AN APPARATUS FOR BOTH BOYLE’S AND CHARLES’S LAW.
BY C. E. LINEBARGER,
Lake View High School, Chicago, III.
The apparatus consists of an open and a closed manometer,
both straight and vertical, and made of glass of ordinary size,
with their lower ends dipping into mercury contained in a.vessel
connected with an air compressor. To vary the temperature of
the air within the closed manometer, this may be surrounded
by a jacketing tube (not shown in the figure) through which
liquids at different temperatures or the vapors of boiling liquids,
such as water, ether, acetne,
carbon tetrachloride, alcohol,
etc., may be. passed.
The open manometer Is
about no cm. long and passes
through one of the holes of a
thrice perforated stopper.
The closed manometer is
about 60 cm. in length and
passes through a second hole,
while the third hole is pro-
vided with an L-tube. The
lower ends of the manometers
should be rotated in a flame
until they fuse nearly to-
-
gether, leaving an opening
about a millimeter in diam-
eter; this will prevent undue
surging of the mercury when
forced up into the tubes. The
upper end of the closed ma-
nometer should be as nearly
flat as it is possible to make it
so that no’ correction need be
applied to the volume (actu-
ally measured as a length on
the assumption that the bore
of the tube is uniform) on
account of the convexity of
the end. It is well to have the
upper end of the open ma-
, APPARATUS FOR BOYLB’S LAW 371
nometer flared out like a funnel, or fitted with a cork over which
is fixed a broken test tube, such an arrangement preventing the
overflow of mercury, which may otherwise happen should the air
in the vessel be compressed too rapidly.
The stopper is fitted to a screw cap bottle, and a circle punched
out of the cap just large enough to accommodate the three tubes.
To fill the closed manometer with dry air, connect it with a
chloride of calcium tube and pass a Bunsen flame along it until
its entire length is heated nearly to redness. Let it cool to the
temperature of the room, disconnect from the drying tube, and,
before any considerable amount of the’ dried air can escape, dip
the open end of the tube into vaseline. The short plug of vas-
eline that will enter the tube effectually seals the dried air unless
it is heated too much by handling.
Fill the bottle to a depth of about three centimeters with clean
and dry mercury, cover the mercury with a thick layer of cal-
cium chloride1, insert the stopper into the neck of the bottle,
and push the ends of the manometers down nearly to the bottom.
Screw on the cap and, connecting a bicycle valve and pump to
the L-tube by means of rubber tubing, pump air into the bottle
until the stopper is forced up snugly against the cap. It may
be found necessary to bind the rubber tubing by wire or string
both to* the L-tube and to the bicycle valve.
Remove the bicycle valve and pump and substitute an exhaust
pump. Close the upper end of the open tube with a tiny lump
of beeswax. Exhaust the air in’the bottle a little, and then dis-
connect ; the mercury will rise in the tubes. Continue the ex-
haustion by degrees until the mercury rises to a distance above
the stopper equal to about a fourth of the length of the closed
manometer. Replace the rubber tubing connecting the L-tube
to the bicycle valve, interposing a screw cock and binding the
rubber tubing to the valve and L-tube.
The jacketing tube is a piece of wide and thin glass tubing
with its ends flared a little for the reception of stoppers, and is
a little longer than the portion of the closed manometer extend-
ing above the screw cap. Its ends are closed with two-hole stop-
per’s, one hole of each of which is fitted with an L-tube, while
the closed manometer is thrust through the other hole of the
lower stopper, and a thermometer through the remaining hole of
the upper stopper.
^To prepare perfectly dry calcium chloride in thin cakes or plates, proceed as follows:
Heat a lump of the chloride held by crucible tongs in a large blast flame. The chloride^
will fuse and the drops that fall from the lump are cauarht upon a plate or a piece of sheet
metal.
