Of a Country on the Climate. 209 
singularly contrasts with its geographical position, and, is 
undoubtedly very much owing to the superficial features of 
the country. 
Evaporation.—The amount of evaporation from lakes and 
running streams has not received that attention from men of 
science to which it is justly entitled, and the consequence is 
an exaggerated estimate of the amount of evaporation in 
warm climates, amongst those whose attention has not been 
specially directed to its consideration. It may not be out of 
place here to mention briefly the conditions which are favour- 
able to evaporation, and to show how clearly dependent is 
this force upon all other atmospheric phenomena, being in 
itself merely the result of secondary causes, governed by 
the geographical position of the country, and its confi- 
guration. 
In the first place, it must be-remembered that evaporation 
is dependent on three very uncertain conditions of the atmos- 
phere—namely, the degree of saturation, the temperature, 
and the force of the winds. The climate of Victoria, during 
the summer months, is very warm—the thermometer not 
unfrequently indicating 100° in the shade—and if the wind 
is from the north, the dew point oftentimes falls below 35°.* 
Such a condition of the atmosphere is most favourable to 
inches!# Jn like manner, in India, Colonel Sykes found, by observations made 
in 1847 and 1848, that in places situated between 17° and 18° N. lat., on a 
line drawn across the western Ghauts, in the Deccan, the fall of rain varied from 
21 to 219 inches.” The average in Bengal is probably below 80 inches, yet 
Dr. G. Hooker witnessed at Churraponjee, in 1850, a fall of 30 inches in 24 
hours; and in the same place, during a residence of six months (from June to 
November), a fall of 530 inches! ”— Principles of Geology, p. 200. Sir R. I. 
Murchison, in hisaddress at the anniversary meeting of the Royal Geographical 
Society, 24th May, 1852, also gives some curious information on this point. 
He says, ‘‘ My friend, Professor Oldham, in writing to me from Churra Poonjee, 
in the Khassya Hills, north of Calcutta, states that the rainfall is there about 
600 inches, or 83 fathoms per annum; 550 inches of which descend in the six 
rainy months, commencing in May; and that in one day he measured a fall‘ of 
25°5 inches.” . . . . “The annual amount of rain at Alexandria stands in con- 
trast to that which I have just mentioned as occurring in places in India, the 
quantity at the former being only 73 inches. This quantity, indeed, might be 
expected to be small, from our knowledge of the fact that, three or four degrees 
to the south, the country is nearly rainless.” 
* These figures, however startling, are not overstated. On Sunday, Decem- 
ber 11th, 1854, at 114 a.m, the thermometer indicated a temperature of 990, 
and the dew-point fell to 35°; the wind, during that state of the atmosphere, 
blowing in strong gusts from the north. On December 13th, at 4P.M., the 
* Miller, Phil. Trans. 1851, p. 155. > Phil. Trans. 1850, p. 354. 
AA 
