444 



to lliis end of the tube was then closed. By means of a Topler 

 pump and a suitable arrangement of glass connecting pieces the 

 resistance was (hen twice rinsed with helium and finally helium to 

 a pressure of 51 cm. was admitted; after this the glass tube was 

 sealed at the narrow part provided for the purj)Ose. (F'or the final 

 form see fig. 2 of Conim. N'. IQOh.) In this way in Dec. 1916 

 were prepared 77-VIll-/P/6\ diameter 0.2 m. m. with a joint in 

 the bifilar wire, and 7Y-IX-/9/6, diameter 0.5 m.m. 



^ 2. Zero determinations. For determining the zeros, the resistances 

 Ti-YlU-WW and Tl-\)L-1916 were placed in glass tubes filled with 

 liquid paratTin (owing to the war conditions no iso[)en(ane could be 

 had) or with distilled benzine; the tubes were closed by corks, over 

 which a layer of paraffin was laid. They were placed in ground ice, 

 and the fiist measurement was made two hours later and repeated 

 with intervals of about half-an-hour. The method of measuring used 

 is either that of overlapping shunts in accordance with Kohlrausch, 

 or that of the compensation of the potential at the terminals of an 

 unknown and a known resistance, connected in series, by means 

 of a compensation apparatus free of t her mo-forces in accordance 

 with DiEssELHORST and provided by 0. Wolff. Enclosing the wires 



TABLE I. 



