Chapter XIII

The ether. Its nature considered. Behaves like a gas 226
Can be pumped out of a receive 227
Light and heat do not pass through a tube _in vacuo_.
Laboratory experiments examined 228
Light and darkness in a partial vacuum, though high 229
Electricity not a carrying agent 230
Why there are light and dark strata in a high vacuum 232
The real carrying agent through a high vacuum is the residue
of ether left in it. Digression to consider the aurora 233
How air may be carried to extraordinary heights. Zones of
air carried up are made luminous by electricity 234
Comparison of this method with experiments quoted 236
Experiment suggested to prove whether light passes freely
through a vacuum tube 237
The ether does not pervade all bodies freely 238
It must be renounced altogether or acknowledged to be a
material body, subject to expansion, condensation,
heating or cooling 239
How light and heat pass through glass 239
Temperature of the ether variable. Zodiacal light, cause of 240