132 PROCEEDINGS OF SECTION B. 
fresh air will be caused to enter, and more or less waste or 
soil gases will be expelled. 
Now, if we watch a delicate barometer, such as a glycerine 
barometer, we can see that, in most places, the pressure is 
undergoing constant variation; and in certain parts of the 
world, where the daily maxima and minima are easily de- 
tected, there will be a great double breath a day—two in- 
halations and two exhalations—besides the short irregular 
breaths produced by gusts of wind, or other causes. The 
great world of mountain and plain is, therefore, constantly 
breathing. We can understand that it must be so, but, if 
anyone desires ocular demonstration, let him descend an 
alluvial mine, as at Allandale, Victoria, and, with lighted 
candle in hand, stand by the entrance to an abandoned drive 
that has been imperfectly closed. Let. him hold the candle- 
flame opposite any of the cracks that are sure to remain, and 
he will find his candle-flame in a constant state of unrest, 
blowing in towards the drive or blowing out from it. He 
will then have seen the breathing of the earth. He may 
prefer to say it is the atmosphere breathing, and not the 
earth, but the result is the same. The earth pulls and the 
sun pulls and warms. 
A breathing earth, with an earthquake shock every half- 
hour, and a trembling seismometer that feels its heart beat— 
what would Thales and his followers have given for such 
information, when arguing that the earth was a living bemg! 
or how much of it all had they devined ? 
If vegetation exists on this arable soil we are considering, 
then there is another obvious action at work. Vegetables 
exhale moisture—some in enormous quantities; the moisture 
is drawn up through their roots by capillarity, &c., and ex- 
haled by the leaves. They are pump-wells; but, if the 
water is pumped away from the soil round the roots, air will 
be drawn in to take its place. or water carrying air. 
This must follow the draining of the land, of country, of 
strata, or of a mine. 
Besides the oxidising, carbonating, or other chemical 
action of the air upon soil and rocks, on the surface or at 
depths, and the rapid combustion or gradual decay of animal 
and vegetable matter, we have the interesting air-traffic tra- 
versing the two kingdoms of plant and animal. As all the 
world knows, the animal as a living heat-engine feeds the 
flame of life with the oxygen of the air, burning its sub- 
stance, and producing as waste, amongst other substances, 
carbon dioxide and water. The plant, reversing the opera- 
tion, decomposes the carbon dioxide, and builds the carbon 
