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ANNIVERSARY ADDRESS. 19 
consistency of hair-oil (for want of a better simile), whisky froze 
hard, and we were able to break off pieces and eat it. Concen- 
trated rum, 30 o.p., also froze hard in a shallow saucer, and in 
a bottle resembled frozen honey or molasses in regard to thick- 
ness. Onchloroform, however, no apparent effect was produced. 
The lowest mean temperature for twenty-four consecutive hours 
was — 70°3); for thirty-six consecutive hours it was — 69°93, and 
for six days the mean was — 60° or 92° below freezing point. 
Latitude of station, 83° 20’ 26’. May 12, 1876.” 
It will be remembered that the lowest temperature ever 
recorded in balloon experiments was 44° below freezing point 
— 12°, at six miles high (32,000 feet), on September 5, 1862. 
I have already detained you too long, and with just an allusion 
to an interesting question raised by Mr. J. A. Brown, of London, 
I will close. Mr. Brown, in a paper on simultaneous variations 
of the barometer, shows, from observations made in Europe, Asia, 
Africa, America, and Australia, that during the week, March 31 
to April 5, 1845, all the baromefer curves exhibit a maximum’ 
near the beginning, and another near the end of the week, with 
a minimum near the middle; and he asked whether there may 
not be ‘other causes of varying atmospheric pressure than a change 
of the mass of the air; in other words, whether the attraction of 
gravitation is the only fone concerned in barometric oscillations. 
Admiral Fitzroy strongly objected to the theory that the curve 
of the barometer indicated the height of atmosphere over it, or 
that it represented atmospheric waves; and he thought these 
effects were due to the action of the polar and equatorial currents 
on each other, and showed that these waves of pressure travel to 
north-east and south-west, and are quite distinct from the local 
changes in pressure due to storms, &c. Their rate of motion 
also is quite different from that of storms, which make from 4 to 
6 miles per hour only ; while these waves of pressure travel here 
over south-eastern Australia at the rate of 20 miles, and in some 
eases 50 miles an hour. They are a very warked and interesting 
feature in our meteorology, and their uniform progression over 
the whole of south-east of Australia at the rate mentioned seems 
. 
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