5o6 
PHYSICS: P. W. BRIDGMAN 
Proc. N. a. S 
ments on them had been already made for another purpose, 
sition of the alloys is as follows: 
Ni 80%, Cr 20%. 
The compo- 
Hoskins 
Mfg. Co. 
Electrical 
Alloy Co. 
'Chromel A 
Chromel B 
Chromel C 
Ni 85%, Cr 15%. 
Ni 64%, Cr 11%, Fe 25%. 
Driver 
Harris Co 
Comet Ni x%, Cr y%, Fe z%. 
fTherlo Al 2%, Mn 13%, Cu 85 (this is Hke Man- 
ganin). 
[No. 192 Alloy Ni 30%, Cr 2%, Fe 68%. 
Only a very rough summary of the principle results of the measure- 
ments can be attempted here. The results will be published in full detail 
elsewhere. In the table are shown the average pressure coefficients to 
12000 kg., and also the initial coefficients at atmospheric pressure. The 
numerical values of the table may be supplemented by the following 
remarks on various significant aspects of behavior. 
TABLE 
Effect of Pressure on Resistance 
Substance 
Li, solid, O'' 
Li, liquid, 240°. 
Na, solid, 0°. . . 
Na, liquid, 200' 
K, solid, 25°. . . 
K, liquid, 165°. 
Mg, 0° 
Ca, 0° 
Sr, 0° 
Hg, solid, 0°. . . 
Hg, liquid, 25°. 
Ga, liquid, 30°. 
Ga, solid, 0°... 
Ti, 0° 
Zr. 0° 
Mean 
Pressure 
Coefficient, 
0-12000 kg 
+ 0 . 06772 
+ 0.0693 
— O.O4345 
—0.0.1436 
— O.O46O4 
—0 . 04809a 
—0.06408 
+ O.O4IO6 
+ O.O468O 
—0. 042366 
— O.O4219 
— O.O553I 
— O.O5247 
—0.0640 
Instan- 
taneous 
Pressure 
Coefficient 
at 0 kg. 
+ O.O568 
+0 . 0693 
— O.O4663 
— O.O4922 
— O.O3I86 
— O.O3I68 
— O.O5447 
+ O.O4I29 
+ O.O45O2 
O.O4334 
—0 . 06640 
-0 . 0640 
Substance 
Bi, liquid, 275° 
As, 0° 
W, 0° 
La, 0° 
Nd, 0°. 
Carbon, amorphous, 0° 
Carbon, graphite, 0°. . , 
Si, 0° 
Black phosphorus, 0°.. 
Chromel A, 0° 
Chromel B,0° 
Chromel C, 0° 
Comet, 0° 
Therlo, 0° 
No. 193 alloy, 94° 
Mean 
Pressure 
Coefficient, 
0-12000 kg. 
— O.O4IOIC 
—0.0633 
—0.06135 
—0 . 06331 
— O.O5213 
— O.O4IOO 
+ 0.0647 
— O.O4II7 
— O.O48I 
—0.06134 
—0.06169 
—0 . 0642 7 
— O.O524I 
—0.06228 
—0.06179 
Instan- 
taneous 
Pressure 
Coefficient 
at 0 kg. 
— O.O4I23 
—0.06143 
—0.0639 
—0 . 05238 
— O.O4II8 
+ O.O577 
-O.O32OO 
-0.06263 
-0.0623 6 
a Average 0-9000 kg. 
b Average 7640-12000 kg. 
c Average 0-7000 kg. 
With regard to purity, Ga was prepared under the direction of Pro- 
fessor T. W. Richards for atomic weight work, and had less than 0.01% 
impurity. The Na, K, Mg, Hg, Bi, W, and black phosphorus were also 
of high purity. The Ca contained about 0.1% impurity, and the impurity 
in the Li and Sr was of the order of 1%^ The Ti and Zr were known to 
be impure with 1.8% and 0.6% of W respectively; the impurity may have 
been higher. Judging by the temperature coefficients of resistance, As, 
