LECTURE ON CLIMATE. 
5 
north-east wind. On the other hand we can per- 
ceive how a like particle of atmosphere, that 
starts from the equator, to take the place of the 
other at the pole, would, as it travels north, in 
consequence of its vis inertia, be going towards 
the east faster than the earth, it would therefore 
appear to be blowing from the south-west, and 
going towards the north-east, and exactly in the 
opposite direction to the other. Writing south 
for north, the same takes place between the 
south pole and the equator. Such is the process 
which is actually going on in nature. 
The sea breeze, so grateful to the residents of 
tropical climates, is an example of a wind caused 
bv rarifaction, the earth, neated by the sun, 
rarifies its atmosphere, causing a partial vacuum, 
and the cold air from the ocean rushes in to fill 
this, causing the afternoon sea breeze. 
The Aurora Australis must be mentioned with 
the few remarks I shall offer on atmospheric 
electricity ; the Aurora Borealis of the northern 
hemisphere was formerly supposed to be occa- 
sioned by the refracted rays of the setting sun, 
from and upon mountains and fields of ice, and 
indeed to one on the spot it seemed a reasonable 
explanation ; in this situation amongst the ice it 
was often a most glorious sight — a trembling 
rose-colored flame at north, making a broad path 
of light over miles of field ice to the ship’s side 
of the beholder rapidly fading away, and theD 
bursting forth with increased intensity of color — 
now down to the horizon, and then flaming up 
with lines and flashes of light almost to the 
zenith. The aurora is seen here at south, as at 
north in the other hemisphere, 1M in my ex- 
perience of the two does not equal 
the borealis in beauty, though some 
writers have stated the southern polar light 
to be the most vivid and beautiful. The following 
short account of the aurora of September 2nd, 
1859, which you will all remember I wrote at 
the time: — “After a clear hot day a brilliant 
polar light was seen, as on the night of the 29th 
August, it commenced at S. soon after sunset and 
continued vivid and beautiful until near mid- 
night — very vivid at 10 p.m., when the moon set, 
lines of lighter light flashing up towards the 
zenith, the whole mass of red fading and increas- 
ing in color rapidly in different parts of the 
aurora. Stars could be seen faintly through the 
red, and from time to time flashes like lightning 
behind it — the whole like a burning 
mass at S., varying in position, 
colour and flashes in a wonderful manner : at 
times as intense as the red fire of the theatres, 
and then in a minute almost gone.’’ At this 
time in Sydney the electrical currents became 
so disturbed that during the day messages 
could not be sent through the electric tele^ 
graph, Mr. Scott, the Astronomer, was applied 
to, to explain this, but, if I remember rightly, 
was not able to do so in a very satisfactory 
manner ; but in the evening the Aurora, as 
with us, made its appearance. It is certain, 
therefore, that the appearances which attend 
this phenomenon are electrical, and as Dr. 
Lardner says, “ Whatever he its physical 
cause, it is evident that the theatre of its 
action is the atmosphere ; that the agent to 
which the development is due is electricity, 
influenced in some unascertained manner by 
terrestrial magnetism.’’ In speaking of the 
formation of hail, mention was made of clouds 
charged with electricity of opposite kinds. 
The atmospheric ocean, more than forty miles 
in depth, and at the bottom of which we live, 
is charged with positive electricity, and is the 
theatre of stupendous electrical phenomena ; 
the surface of the earth being charged with 
the opposite or negative electricity. It is a 
well known law of electricity that bodies 
charged with the same kind of electricity repel, 
while those charged with opposite kinds attract 
each other ; and so it is, that when two clouds 
charged with opposite electricity approach so 
near that their electricity surpasses the resist- 
ance of the air, the fluids rush together, a flash 
with sound follows, and lightning and thunder 
are produced. Exactly the same thing occurs 
on a small scale when a spark escapes from 
the charged Leyden jar. All of you are doubt- 
less aware of the experiments of Franklin, who 
drew electricity from the clouds with his kite, 
and which nearly cost the philosopher his 
life. Subsequently, by the same means, blades 
of fire many feet long haye been drawn from 
clouds, and with a report as loud as that of a 
pistol. Allied to the electric spark — (and which 
is the last matter in the history of climate which 
I have to notice)— is a newly discovered substance 
called ozone , and which is now being diligently 
investigated, and is exciting much attention, 
from the probability that it will throw light upon 
the origin and history of diseases, and ultimately 
lead to improvement in the treatment of them. 
Ozone, so named by Professor Schonbien from the 
Greek “ozo” — I smell — is generated by the 
passage of a series of electric sparks through 
dry oxygen, or atmospheric air. This odourous 
air emits a peculiar and somewhat metallic 
odour ; it assumes several properties not exhi- 
bited by pure oxygen, the most curious of which 
is the liberation of iodine from iodide of potas- 
sium. Schonbein considers ozone to be a volatile 
peroxide of hydrogen ; Dr. Andrews, a modifica- 
tion of oxygen. Its presence in the air may be 
ascertained by slips of prepared paper, freely 
exposed to the air, the light being partially shut 
off ; the papers are easily made, and are inex- 
pensive, and as some persons might feel inclined 
to make regular ozonometrical observations, I will 
add two receipts — Professor Scboubein’s and Dr. 
Breed’s, of Washington. Schonbein’s is— water 
200, starch 10, iodide of potassium 1; strips of 
paper, half an inch by three inches, are soaked 
in this, and dried, being kept in a close dark 
vessel for use. Breed’s receipt is— starch 10, 
iodide of potassium 20, water 400 parts ; the 
papers are freely exposed to the air each day, 
and, when removed, compared with a scale of co« 
