S. H. Freeman—Electrification by Evaporation. 433 
Il. Zable showing results of later series. 
§ g 5 a a ee 
Liquid Ese ers uae geale | £5 = a W in A ees 
ase gs SE S SE BS divis- divis ~8 tes, | grams. | in e.m. 38 is 
5 2 A a ons. ns. EB RES 
o Rn 
Saturated solution 
CuSO, 0°3 00 | +0°3 376 21 1%4 id Fy 198 a 
a 0°12 6 0° 376 2) 1%74 319 99 a: 
Sy 0-8 06 |+0°2 376 | 10 | 174 | 3:19 | 1482 a 
hy 0°6 0°42 |+0°18; 39°6 | 10 38 0-9 2240 + 
ee 0°5 0-21 |+0°29; 39°6 5 38 | 09 + 
4 01 0°21 |—O°ll | 39°6 5 38 09 1833 as 
mn 0-3 0°21 |+0°09; 39.6 5 38 0-9 2240 > 
Saturated solution | 
NaCl 0 0°35 |—0°35| 39°6 6 30° | 0°54 525 _- 
es 0-2 0°12 |+0°08) 396 2 30 | 0°54 7 + 
ts 0-4 0°35 |+0°05| 39°6 6 30 0°54 | 3678 + 
Hydrant water 1°6 06 |+1°00;} 37°6 | 10 30 0°59 318 + 
1°45 06 |+0°85} 37°61] 10 30: 1: O59. 373 + 
" 06 (|+0°70! 37°6 | 10 30. | 0°59 454 + 
Disiled water 0°5 06 |—0:10| 39°6 7 35 0°89 | 3031 _ 
Cotton wet with 
hydrant water | 1:0 0°66 |+0°34! 876! 11 | 30* | 0-59*! 1029 + 
The actual value of 4 (the virtual depth of ee we a cloud 
1500 meters thick, f condensatio 2s ig t 35° C. is about 
5°9 e«m.; at 80° C. is about 4% ¢ at 95° C. : aback 34 
c.m.; at 20° G se uhoet Soca ° C. is about 1‘9 ¢.m. 
Hence, aie if the deflections a ‘of we tables are really due 
to evapora and if evaporation be the principal source of 
the saps slecuidity, the quantity of seats. which oar 
be required to produce a single flash of lightning, i is very m 
greater than the actual quantity ever found in a tnunder clo, 
while a thunder-cloud usually gives not one but ma ashes. 
It may be objected to this reasoning that a Srilidek cloud in 
hoes on the globe. If 100 ¢.m. be taken as the aang 
age _ for the whole surface of the earth and 400 c.m 
as the value of 4, the total annual evaporation on the 
earth is apr ent to produce only about 14,000,000 flashes of 
lightning from clouds nine ae kilometers in extent. 
ence if one were able to observe every flash of lightning 
which occurs within eighteen se loietere of himself the average 
number of lightning flashes seen by such observers at different 
points of the earth’s surface in one year would be only twenty- 
ce Caleulation from more exact data would give a less 
* In this case the rate of evaporation was not measured, but was assumed in 
Midler nig A to be the same as for hydrant water a “the same Patore The rate 
was probably greater, which would make A still grea’ 
