10 



The o'idium of the vine, for instance, is much more troublesome 

 noist than in dry seasons ; and, for the same reason, in the moist 

 districts close to the sea, than in districts situated further inland, 

 3re the atmosphere is drier. 



For another reason is dry air of value to the fruit-grower. It 

 9urs the better penetration through the atmosphere of heat and 

 it, and their access to the plant. The effect of the chemical 

 s of the sun, which, although not appealing to our senses in the 

 le measure as its thermal rays, are nevertheless essential in 

 iging about the perfect ripening of fruit. Now, a layer of vapour- 

 en atmosphere floating over the earth acts as a screen, which, 

 lough pervious to the heat rays, shuts off in a great measure 

 chemical rays of the sun. . A practical illustration of this fact 

 been noticed by everyone. However hot the season, fruit will 

 3n slowly and rot on the plant if the atmosphere is dull, moist, 

 L muggy ; whereas in a dry and bright autumn, fruit will be 

 respondingly luscious and richly flavoured, and will put on the 

 ?htest of those tints of colour by which each variety is differ- 

 iated from the other. 



Mean Monthly Relative Air Humidity August to April- 

 Annual. (Saturation = 100.) 



ind Mean 



THE RAINFALL AND WATER SUPPLY. 



The rainfall of the zone running along the sea coast of Western 

 stralia for a distance of 80 to 100 miles from the coast is regular 

 L reliable. More abundant in close proximity to the seashore, 

 L also on the higher table land of the Darling Ranges, the 

 ifall gradually decreases the farther inland we go. 



