MEETINGS OF ‘SOCIETIES. 577 
that if a fully saturated wind at a temperature of 55 deg. F. had to 
cross a range of mountains 7,200 feet high, the wind on the dry 
side would have a temperature of 75 deg. F. If observations at 
Hokitika be compared with those taken at Lincoln or Christchurch 
in nor’-westerly weather, it will be found that the maximum tem- 
perature in the shade at Hokitika is some 15 deg. to 20 deg. F. 
lower than at Christchurch ; while the humidity of the air is go 
at the former and only 45 at the latter place, taking 100 as repre- 
senting complete saturation. 
Mr. Hogben did not agree with Dr. Hector’s theory, given in 
Sir C. Lyell’s “‘ Principles of Geology,” that the hot winds were 
heated in Australia. Our north-west winds almost always changed 
to south-west, which showed that both were parts of a cyclone dis- 
turbance with the centre of depression passing in an easterly 
direction south of Canterbury, and as the south-west wind was not 
hot, the heat of the north-west wind must be due to local causes. 
The occasional change from north-west to north-east would be due 
to an anticyclonic disturbance round a centre of elevation. 
Mr. Inglis said that the wind was often cold on the plains at 
the foot of the hills when it was a hot wind in Christchurch. The 
wind was often still on this side the hills but blowing violently at 
the top of the pass. The wind felt cold in the mountains, but it 
melted large quantities of snow. 
Dr. von Lendenfeld agreed with Mr, Barkas. Exactly the same 
thing occurred on the north side of the Swiss Alps, but the wind 
there changed in the opposite direction owing to its being in the 
northern hemisphere, so no doubt Mr. Hogben was right. The 
wind changed suddenly from the N.W. to S.W. because the moun- 
tains prevented the wind blowing directly from the west. The 
wind was cold at the foot of the mountains because the hot wind 
blew higher and came down on the plains further off, this caused 
a backward whirlwind of cold air. He said he found in his observa- 
tions on the Alps that the barometrical curves there were ahead of 
those at Hokitika, although from geographical position they ought 
to be behind them. He explained that by supposing that the. 
centre of depression formed a vertical line while on the sea, but 
the friction of the land caused the lower portion to move slower 
than the upper, and consequently the line of greatest depression 
got inclined, and in this way he would account for clouds moving 
in different directions at different altitudes. 
The President thought that the theory brought forward by Mr. 
Barkas was quite correct, and gave an excellent explanation of 
the phenomena in outline, but many details had yet to be filled 
in. As the wind ascended the mountains it gained by giving 
out latent heat about as much sensible temperature as it lost 
. by rarefaction, and therefore it would keep approximately the 
same temperature during the whole of its ascent; this no doubt 
was the cause of the snow being melted, but he could not un- 
derstand why the wind should feel cold. 
Mr. Barkas explained that the wiud felt cold on the top of 
the mountains because it was nearly saturated with moisture. 
Mr. McKay in a paper in the Transactions had pointed out that 
the wind often blows from the south at the foot of the hills, 
while a nor’-wester is blowing higher up. Dr. Lendenfeld’s ex- 
planation accounted for this, As the foot of the mountains were ~ 
