(116) 
uneertainty in the temperature of the steel capillary was of the same 
magnitude and has the same influence here as in the former section. 
The values of pva used for the calculations in this section were 
obtained by interpolating graphically the values given above. 
The following determinations were made. 
TABLE XIV. 0, at 0°.0 €. 
Determinations. p | PvA 
Series /// n°. 6 22.401 0.9762 
4 27.746 0.9731 
Series JJ n°.3 34.498 0.9672 
6 38.144 0.9656 
Series VY. n°. 9 43.686 0.9623 
10 48.756 0.9608 
Series JZ, n° 8 45.238 | 0.9612 
10 | 48.69 ie del 0.9584 
Series // n°. 5 55.017 0.9533 
6 60.301 0.9508 
| 
7 66.787 | 0.9477 
Physics. — Communication NO. 78° from-the Physical Laboratory 
at Leiden: “Zsotherms of diatomic gases and their binary 
mixtures. IV. The compressibility of Hydrogen at 0°.0 C. 
and 20°.0 C. determined by the piezometers with variable 
volume for low temperatures. By Prof. 1. KAMERLINGH ONNES 
and H. H. Francis HYNDMAN. 
§ 15. The object of the determinations at 20°.0 is the direct 
comparison of an isotherm determined by our method with an if 
possible more carefully determined one to serve as a check. The 
isotherm given by ScHALKWIJK in Comm. N® 70 V was chosen as 
the most accurate known to us and we treat it as our patie of 
reference in these measurements. 
Determination of compressibility were also made at 02.0 C. to coma 
pare directly with AMAGAT’s determinations at the same temperature. 
