156 DE, M. W, TEAVERS, ME. (i. SEXTEE, AXD DR. A. .TAQUEEOD 
The boiling-point of liquitl oxygeii ^^"as nieasuved in (iveiy case as a clieck on the 
results. 
The results obtained h);" means of the hydrogen thermometer filled under a pressure 
of 739 millims. of mercuiy dilfer from the mean of our observations by 0°'l. The 
difterence between this result and those obtained in experiments (a), (//) and (c) is 
certainly due to experimental error, since the temperatures determined by means of 
a gas theiinometer should rise when tlie pressure on fhe gas in the thermometer is 
reduced. Since the pressure on the gas in the thermometer was in each of these 
experiments very small, the experimental error was proportionally large, and much 
greater weiglit must he attached to the last measurement. 
The results obtained by means of the helium thermometer are lower than those 
ol Rained by us, though the difference is not constant. 
Pi'essure. 
Temperature. 
1 
1 
Dewai:. 
T. and J. 
I 
1 
A. 
770 
°c. 
-252-St 
- 252•57 
! 
c 
0-27 
765 
- 252•68 
- 252■60 
0-08 
Olszewski (‘Phil. Mag.,’ 1895 (5), vol. 39, p. 199; vol. 4U, p. 202) employed the 
following method: Hydrogen was compressed to 170 atmospheres into a steel 
cylinder, with a loose glass lining enclosing the platinum coil of a resistance thermo¬ 
meter, of which the resistance had been determined at 0°, — 78°, — 182°’5 and 
— 208° C. The cylinder vns cooled in licpiid air, boiling in vacuo, and the gas was then 
allowed to escape from the cylinder. When the pressure fell to one atmosphere the 
resistance of the coil was measured, and the temperature determined by linear 
extrapolation. As the result of numerous trials, he found the temperature to lie 
- 243°-5. 
Though the method gave accurate results for the boiling-point ot oxygen, the 
results are of no value so far as the temperature of licpiid hydrogen is concerned, as 
the variation of the resistance of platinum with the temperature is not linear. 
Beyond determining the boiling-point of licpiid hydrogen on fhe scales of the two 
thermometers, Dewae (‘ Bov. Soc. Proc.,’ vol. 68, p. 360) finds the melting-point 
on the helium scale to he 16°; an earlier determination by him gives the melting 
pressure as 55 millims. (T. and J. find 14°'l and 49 millims. respectively, p. 170.) 
He also gives the following values for the temperatures of solid hydrogen corresponding 
to very low jiressures (/or. cit.) :— 
