154
7.
THE OUTER PARTS OF THE ATOM
EXPERIMENT 7—2
IONIZATÏON AND EXCITATÏON POTENTIÀLS OF MERCURY
"
Âpparatus.—The circuits are shown in gure 7—10. The la—
ment of the FG—17 tube operates on 2.5 volts and 5 amperes.
The lament must be of the at spiral rather than the V type.*
The tube is Operated in a vertical position in an electrical furnace
wound non—inductively. A rheostat (7) is used in series With the
furnace to vary the temperature.
The mercury or thermo—
couple thermometer should be capable of reading up
to 250° C
'
_OVEN
3
:. GA
G
\\,
; _
FEN”
ONE —
\
fDRY+
|"
-
1
°
0
-—: a-‘—:
:-—1=5;:
°VEN CEU—
2
:
L.%Ë.
55
-S
.
‘:
'F
r
R
I
‘
sorrom vuew
G
..
,
_
.
OFF—“ G BΫ_Ï$E
nov
l”|
[IO
3
$
+
……
-
ACË…Œ
'
45 v
_
‘
FIS. 7—10.
Circuits for measuring critical potentials of mercury.
The
Ga must be sensitive (IO—9 to 10—10 amperes
per millimeter on a scale one meter away) and is provided
With a
shunt (s). ‘ The retarding potential on the plate may
be 0.5 to 15
_
for the V
x
measurerents._ The voltmeter (V) may havea
'
_
,
0 to 50 volts.
_
_f
Heat the lament before applying thegrld
_
_
voltage. 2.
_
After heating the-tube
given temperature (W1th
the
wa1t one—half
taking readings 1norder
,
equilibrium. 3.“ Start at the higher voltages
quicklyrun down to the lower voltagCS,_ not
[
.
Ï
'
.
'
"
was P0Ïntéd Out to the ”author by Dr. ]. S. Thompson.
_
7.
THE OUTER PARTS OF THE ATOM
EXPERIMENT 7—2
IONIZATÏON AND EXCITATÏON POTENTIÀLS OF MERCURY
"
Âpparatus.—The circuits are shown in gure 7—10. The la—
ment of the FG—17 tube operates on 2.5 volts and 5 amperes.
The lament must be of the at spiral rather than the V type.*
The tube is Operated in a vertical position in an electrical furnace
wound non—inductively. A rheostat (7) is used in series With the
furnace to vary the temperature.
The mercury or thermo—
couple thermometer should be capable of reading up
to 250° C
'
_OVEN
3
:. GA
G
\\,
; _
FEN”
ONE —
\
fDRY+
|"
-
1
°
0
-—: a-‘—:
:-—1=5;:
°VEN CEU—
2
:
L.%Ë.
55
-S
.
‘:
'F
r
R
I
‘
sorrom vuew
G
..
,
_
.
OFF—“ G BΫ_Ï$E
nov
l”|
[IO
3
$
+
……
-
ACË…Œ
'
45 v
_
‘
FIS. 7—10.
Circuits for measuring critical potentials of mercury.
The
Ga must be sensitive (IO—9 to 10—10 amperes
per millimeter on a scale one meter away) and is provided
With a
shunt (s). ‘ The retarding potential on the plate may
be 0.5 to 15
_
for the V
x
measurerents._ The voltmeter (V) may havea
'
_
,
0 to 50 volts.
_
_f
Heat the lament before applying thegrld
_
_
voltage. 2.
_
After heating the-tube
given temperature (W1th
the
wa1t one—half
taking readings 1norder
,
equilibrium. 3.“ Start at the higher voltages
quicklyrun down to the lower voltagCS,_ not
[
.
Ï
'
.
'
"
was P0Ïntéd Out to the ”author by Dr. ]. S. Thompson.
_