THE GEELONG NATURALIST. X 
ON RAIN. 
By Mr. S. PATTERSON, B.A. 
I Hore I have not chosen a “dry” subject. At the outset I 
would inform you that I shall not attempt to overwhelm you 
with any statistics on the subject, but will strive to indicate 
a few of the general laws which govern the production of that 
all-necessary and, to us in this country, much-needed, gift of 
Nature—Rain. / 
We cannot but be struck by the fact that the whole grand 
total of material life is the outcome of the balancing, and 
the setting off, by a Master-hand of one set of forces, or series 
of effects, against another. Our subject is a case in point. 
Without rain the world would be indeed an arid waste, all 
vegetation dried up and shrivelled by the solar heat; yet this 
effect is prevented by the balancing action, in another direc- 
tion, of this same solar heat, namely, in the production of 
rain. The sun, whose influence we contrast with the rain 
shower, is the agent in producing that shower, as well as in 
pouring out his direct heat on the soil with such apparently 
contrasted effect. 
The idea of the earth being a vast still is one that is familiar 
to all of us. Weare aware that the sun's rays acting on large 
. expanses of water cause¥ evaporation, the vapour produced 
being carried away by winds, or atmospheric currents, and 
finally re-condensed by various causes and deposited over 
the earth's surface. Before going into any of the details of 
this process, it might be instructive for us to consider the 
consumption of energy involved— the actual work done. 
The falling of a gentle shower, or even of a heavy down- 
pour, does not suggest to us an impression of great power; 
yet the forces actually called into action before rain can fall 
are among the most gigantic experienced on our earth. Let 
us look into the matter a little more closely, and we shall see 
that this is so. 
It is a common occurrence for rain to fall over an area of 
100 square miles, to a depth of r inch in twenty-four hours. 
Now, what is the expenditure of power of which such a 
phenomenon is the equivalent? The evaporation from the 
sea, or from moist soils, of the quantity of water precipitated 
is not the whole of the work to be estimated, since the 
vapour has to be raised to the higher regions of the air, and 
has to be wafted by the winds to the district over which the 
moisture is discharged in rain. But let us take the evapora- 
tion only, and consider its real force equivalent. It may be 
