430 3S. H. Freeman—Electrification by Evaporation. 
ae electrometer were connected with earth. By means of a 
mercury commutator the evaporating dish and its connections 
could also be connected with earth. The evaporating dish was 
supported on a wire frame suspendéd by silk threads. To aah 
vent disturbances ius to electricity on ish ap Sale spendin par 
ticularly the clothes of the observer, it was found necessary to 
enclose the whole apparatus in a metallic case. sohanie were 
made in this case to facilitate Sella and to permit the 
mirror of the electrometer to seen. e commutator was 
governed ye a silk thread assitig through an opening in ae 
case. In experiments, the results of which are give 
table II, the aucune dish was of copper; in the other cases 
three were most carefully studied, water and NaCl because of 
their importance in evaporation in nature, and CuSQ, because 
of the very large deflections which Tait and Wanklyn ‘obtained 
with it 
The electrometer was about thirteen times as sensitive as 
Professor Tait’s. Its deflections were reduced to absolute 
measure by comparison with a Daniell’s oak, the deflections 
produced by which were observed before and after each series. 
The capacity of the evaporating dish and its connections was 
found by comparison with Sees Rowland’s ecient con- 
denser to be 65™ nearly. The rate of evaporat as deter 
mined by weighing the ceeean dish and hand ‘afore and 
after each series. It was found impossible to eliminate ever 
source of electricity fibers evaporation, since deflections were 
always obtained even with the evaporating dish dry. In order 
to correct for this each series began and ended with tw 
a known ms usually five minutes, the dry evaporating 
amen these observations several similar observations with the 
liquid sapien were made. 
As the result of a large number of observations i in which the 
fie eines niece was insulated for five minutes 
cohol gave a poten —'04 to — a that of 3 Daniell’s cell. 
Fre wet with stobol mee a Ay ge pica es a to 
Sulphuric ether gave a potentia _ 10 . 
Sede sign indiats the Be ples carried away by the 
vapor. r.) No correction has been made in the above figures for 
the deflections bbeacusd with the dry dish, These were more 
variable, but usually of the same sign, as when a liquid was 
evaporating, and of a magnitude not very different, Making 
this necessary correction— 
Alcohol gave a potentia 024 to — foo that of a Daniell’s cell. 
Cotton wet with peer coe ott Wa from — — 028 to 
Sulphurie ether gave a potential oa 4 to oon : » 
