88 Transactions.—Miscellaneous. 
greatly affects the New Zealand climate. Professor Tyndall showed, by 
elaborate and delicate instruments, that the vapour in the air made it 
tolerably transparent as regards the transmission of direct rays, but 
rendered it opaque to the rays reflected from the earth; and he showed, 
further, that the opacity of the vapour of water was 16,000 times greater 
than that of pure dry air, and that this vapour acted as a blanket by 
preventing the escape of heat ; therefore, the greater the quantity of vapour, 
the warmer and more equable the climate, and for this reason the isothermal 
lines agree more closely with the parallels of latitude in the south than they 
do in the north. 
By means of this vapour, as Maury first suggested, much heat is carried 
from place to place; this heat, though latent, is readily liberated by the 
condensation of the vapour. "When the vapour-laden winds strike the coast 
of New Zealand, they are forced by the mountain chains to ascend ; there 
cooled, the yapour eondenses and falls as rain. By the extraction of the 
vapour the air is rendered heavy, and it is also warmed by the large amount 
of liberated heat, His theory explains these phenomena—the raininess of 
the west of New Zealand as contrasted with the dryness of the east coast, 
and the fact that on the eastern side, these winds, though tumbling down 
from cool mountain tops, are yet warm—often hot. This latent heat, when 
liberated, is a powerful agent in increasing the force and regularity of 
winds in this hemisphere. Because of the greater dryness of the air on 
the east coast, the thermometrie variations are there much more marked 
than on the west coast. 
the pressure of the atmosphere is, in the 
; from 101b. to 501b. per square foot less than that in 
the northern hemisphere. The surface of an average man is 85 square feet, 
and such a man in England sustains a pressure of 85,560lbs., or nearly 16 
tons (** Ganot's Physics 7); but in New Zealand the pressure is lightened, 
and though at any one moment this difference of pressure may seem small 
and unworthy of notice, yet it is not really so. Ramifying everywhere 
through the skin are minute blood-vessels ; these, the walls of the chest, 
the air-cells of the lungs, and indeed all the internal organs, are subjected 
to a lessened pressure. This lessened pressure will slightly change the 
cerebral circulation, and will therefore also slightly affect the immigrant’s 
thinking powers. The lessening of pressure on the chest walls, though 
apparently trivial, is not 80, because the immigrant respires 19 times a 
minute ; and if, at each respiration, he lifts only one pound less each time to 
a given height, yet in the 24 hours he will lift 27,500 pounds (i.c., twelve 
