16—17.
METALŒO{GLASS SEALS
‘
,
375'
.
'
To form carbon dioxide snow (C02), a cloth bag of about a_liter
capacity is tied over the opening of the drum of gas; The drum is
tipped up
at an angle of 30° or more with the valve at the bot—
tom so it is below the level of the liquid C02 inside. The valve is
.
opened wide when the liquid, rushing out under high pressure, soon
Ï
.
‘
turns to snow and collects in the sack.
Break up the snow (do not
'
'
pinch it with the ngers), put it in the Dewar
add
acez‘one or alcohol to form a slush.
This insures good Contact with
the trap.
A pint of C02 snow and alcohol will keep for about a
day and a half. In many large cities,carbon dioxide snow is supplied commercially under the name of
“
dry ice.”
_
-
The following table 8 gives the vapor preSsure p in millimeters.of mercury of various materials at room temperatures.
.
*
Substance
/ 1 )
X
m m /
Wax
/ p
X 104 mm.
Pyrex...………………….
0.58
Piceih..…….…….……..
2.9—3.3
__
Brass.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
..
0.83
Dennisoh’s Royal Scarlet
3.7
-
Iron..….….....…...…
2.9
-
1'part, ros1n 1
*
Rustyiron.………………
210.0
part......._....……‘.
4.6
Glyptal..…………………
1.7—5.8
_
8.7
'
_
Stop-cock gœase:
—
Universal wax.
.
.
.
.
.
.
..
10.
'
Cenco.
.
.
.
..
..
.
.
..
5.8
.
‘
Dennison’s#2‘………
10.
Lubriseal..…………….
6.2
-
de
_12—21
16—16.
Mercury Cùt—of‘s.——Figme 16—12
of
'
mercury traps. When “the
chamberÂ1s to6be-sealed
off
.
—
from the
apply air
_‘the mercury
above the cut-blevelin
,
;:.Ï:r
_
'
16—17.
Metàl‘—’to-GIäSS -
the
expan31o'n
.
cOeicients of Îplatinùm andsoftglass arethesamemany leadfm _
wifes are of thlstÿpeumetWlf€maYbeusedsmay
'
…
For 1eadlnw1resthhpyrextungstenmaYbeused (SeeD
_
.
‘
'ïrùbbig5W1thastmkofpetassmmmtffæIt13thenwaShedand f
É
r
7:.
‘
METALŒO{GLASS SEALS
‘
,
375'
.
'
To form carbon dioxide snow (C02), a cloth bag of about a_liter
capacity is tied over the opening of the drum of gas; The drum is
tipped up
at an angle of 30° or more with the valve at the bot—
tom so it is below the level of the liquid C02 inside. The valve is
.
opened wide when the liquid, rushing out under high pressure, soon
Ï
.
‘
turns to snow and collects in the sack.
Break up the snow (do not
'
'
pinch it with the ngers), put it in the Dewar
add
acez‘one or alcohol to form a slush.
This insures good Contact with
the trap.
A pint of C02 snow and alcohol will keep for about a
day and a half. In many large cities,carbon dioxide snow is supplied commercially under the name of
“
dry ice.”
_
-
The following table 8 gives the vapor preSsure p in millimeters.of mercury of various materials at room temperatures.
.
*
Substance
/ 1 )
X
m m /
Wax
/ p
X 104 mm.
Pyrex...………………….
0.58
Piceih..…….…….……..
2.9—3.3
__
Brass.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
..
0.83
Dennisoh’s Royal Scarlet
3.7
-
Iron..….….....…...…
2.9
-
1'part, ros1n 1
*
Rustyiron.………………
210.0
part......._....……‘.
4.6
Glyptal..…………………
1.7—5.8
_
8.7
'
_
Stop-cock gœase:
—
Universal wax.
.
.
.
.
.
.
..
10.
'
Cenco.
.
.
.
..
..
.
.
..
5.8
.
‘
Dennison’s#2‘………
10.
Lubriseal..…………….
6.2
-
de
_12—21
16—16.
Mercury Cùt—of‘s.——Figme 16—12
of
'
mercury traps. When “the
chamberÂ1s to6be-sealed
off
.
—
from the
apply air
_‘the mercury
above the cut-blevelin
,
;:.Ï:r
_
'
16—17.
Metàl‘—’to-GIäSS -
the
expan31o'n
.
cOeicients of Îplatinùm andsoftglass arethesamemany leadfm _
wifes are of thlstÿpeumetWlf€maYbeusedsmay
'
…
For 1eadlnw1resthhpyrextungstenmaYbeused (SeeD
_
.
‘
'ïrùbbig5W1thastmkofpetassmmmtffæIt13thenwaShedand f
É
r
7:.
‘