Meeson. — The Bainfall of New Zealand. 551 



tempex-ature which takes place after the sun sets rendering 

 the air incapable of holding the moisture which was easily 

 borne during the warmer hours of the day. 



Our heavy rains — particularly on the West Coast — must 

 tend to I'ender the air milder, because one gallon of rainfall 

 gives out latent heat suflicient to melt 751b. of ice (Scott) : in 

 other words, every inch of rain could melt Sin. of ice spread 

 over the ground. 



Some people might suppose that the copious rains of New 

 Zealand are sufficiently accounted for by its insular position, 

 but a moment's reflection will dispel such an illusion. As- 

 cension Isle, in the middle 'of the Atlantic Ocean, is one of the 

 driest places in the world. Its rainfall is only 2in. or Sin. 

 annually, and except on the very summit of its solitary hill, 

 Green Mountain, nothing grows on the island except Mada- 

 gascar roses. Again, Maiden Island, and others remarkable 

 for guano deposits, in the Pacific Ocean, are absolutely rain- 

 less. St. Vincent, also, one of the Cape de Verde Islands, is 

 sometimes without rain for three consecutive years. Neither 

 will it do to give our mountain-chains the sole credit for causing 

 our rains, for the rainless desert of Ataco.ma lies at the feet of 

 higher mountains than our Southern Alps. Of the various cir- 

 cumstances that affect climate— latitude, elevation, prevalent 

 winds ; position, direction, and height of neighbouring moun- 

 tains ; slope of ground, character of soil, proximity to sea, and 

 degree of cultivation — not any one can be assigned as the 

 cause of our rainfall, which is simply owing to a combination 

 of several favourable circumstances. What this combination 

 is, it will be for us — inte)- alia — to inquire, and thus we may 

 arrive at the general features of our climate, apart from local, 

 diui'ual, seasonal, and cyclical vai'iations. 



Now the question arises. With such figures of the rainfall 

 of New Zealand as have been exhibited, is it possible to con- 

 struct a map of the colony showing by gradations of shading,. 

 or by diiferent colours, the comparative amount of rain which 

 falls in different parts ? This, as far as I know, has never been 

 attempted, and it must be borne in mind that, apart from the 

 peculiar difticulty of scanty statistics, to construct a rainfall- 

 map at all for a large area of country is no easy matter. Let 

 us remember that the fall at any one spot is by no means an 

 exact criterion of the precipitation elsewhere — even in the 

 neighbourhood. Local circumstances, slope, proximity to sea 

 or hills, &c., all affect the rainfall : and these circumstances 

 are seldom or never exactly the same for any two places, 

 though they may be near together. Yet we register the 

 number of inches in a particular spot, and assume that it is 

 the same over perhaps a wide area round about. Nothing can 

 be more fallacious. 



