497 



first described in Comm. 119 PI. I and more recently in Comm. 1246 

 PI. I fig. 3 and specially designed tor tliermoraetric work. After 

 the improvement of Comm. J '24/> this manometer had only under- 

 gone a slight modification : in addition to the glass-tap in the glass 

 capillary leading to the copper one, a side-tap has been added whose 

 object is to connect the thermometer with the mercury-airpnmp if 

 required. 



-Th, 



Fig. 1. 



Fig, 2. 



The part of the dead space of the theriiiomeler which during the 

 measurements remains at room-temperature had a volume of4 87cc. 



The second thermometer (fig. 3) was provided with a \evy small 

 lieaied-wire manometer') /•, designed to measure small pres^ui'es 

 with sufficient accuracy. The bulb of the iliermomeler had the same 

 volume as that of the first thermoiueler 23.956 cc and the capillary 

 was constructed in exactly the same way as with the latter. The 

 part of the dead space wliicli in this thermometer did not assume 

 the low temperature was 2.67 cc; the liealed-wire manometer stood 



V H. Kambrlingh Onnes and Sophus Weber, Comm N'. 137Ö. 



