26 ANNIVERSARY ADDRESS. 
from the sea. The range rises abruptly to between 4,000 and : 
5,000 feet high, and has between it and the sea a belt of low and 
swampy land. The S.W. monsoon, coming over the Indian Ocean, 
arrives at this part of the coast laden with moisture, which is not 
abstracted, but rather added to, by the warm swampy belt at the — 
foot of the hills. Directly the wind begins to mount the hills the j 
precipitation commences in earnest, and the rain comes down as it | 
does nowhere else. At Cherra Pungee, a town on these hills, 4,200 — 
feet high, the annual rainfall is 600 inches, and of this enormow — 
quantity about 500 inches fall from April to September. On one 
occasion the rain fell at the rate of 30 inches per day for five 
days, and in 1861 the total rainfall for the year reached the | 
enormous quantity of 805 inches. No better example of the effect 
‘of hills on rainfall than this could be chosen. On the coast of New 
South Wales we have the same law in operation, and as & result 58 
inches of rain falls at Cordeaux River, 1,200 feet high (about), for 
39 inches at Wollongong, the foot of the same hill ; and Kurrajong 
at an elevation of 1,800 feet, gets 53 inches of rain for every 
inches which fall at Windsor. At Kurrajong and Windsor the same 
_ proportion is maintained in heavy storm rains with easterly wind} 
but under such circumstances the rain at Cordeaux is double, am! 
sometimes 230 per cent. of the rain at Wollongong. 
4 
: 
If we can get a measure of the force required to produce thes? 
effects, it will serve as a guide im estimating what would be 
required to make rain. At Sydney the average relative humidity 
is 73, and at Windsor it is rather less; and we have just learned 
that such atmosphere lifted from Windsor to Currajong, 1,800 fee 
deposits 60 per cent. more rain. If we could make it rise up 
Sydney 1,800 feet we might fairly expect to get 60 per cent. mo 
rain. Now,awall built 1,800 feet high, and of considerable length: © 
that the wind would not divide and go round it, but go ove 
‘would have the desired effect—i.e., to lift the air and cause rail 
but anything that would do this would serve the purpose, and i 
may be done by fire, but of course the fire must have the effect 
