1920.} Desiccants in Electrostatic Measurements. 3 
electrostatic work, especially in Germany, as for instance by 
Gerdien,' Ebert,’ Hochheim, é Elster and Geitel,* Daunderer, 6 
most modern quartz fibre electrometers. such as the Wulf ® 
and the Lutz’ patterns, as well as in the insulators, specially 
designed for high insulation, such as those of Gockel? and 
others. Nevertheless, we have not been able to trace any 
published measurement which justifies the supposed efficiency 
of sodium as a desiccant for accurate electrostatic work; and 
our own observations, whic ve been carefully verified in 
several ways, lea to the unexpected conclusion tht for 
this purpose metallic sodium is either ineffective or even worse 
than useless. 
In our preliminary measurements we used this substance 
Dracram II. 
Top—Sodium bits (17.10.14—29.10. 14). 
Bottom—Effect of glass stirrer, details in Table Ii. 
z Se fe 2 
“@02 ee 
3S 
> 
| 
a 
801 
ag 
FI 
2 
1 
180 240 300 
fe) 60 120 
—— Time in hours 
cut in small pieces and spread on several dishes, which were 
introduced quickly into the electrometer case. It was natural- 
ly impossible to prevent a certain amount of deterioration 
: akan Zeit. Vol. 5, 1904, page 295. 
I, page 392. 
X, page 51. 
VIII, page 275. 
» » VIII, page 
VIII, Page 246 and Vol. X, page 251. 
» o IX, page 100. 
VI, page 328, 
on aT fF OH 
