ARIDITY OF AUSTRALIA. 301 



spark, and the grass among the trees commonly re- 

 sembles hay. Everything absorbs the heat freely, 

 and radiates it into the surrounding atmosphere. 

 Instead of being cooled then, and precipitating its 

 superabundant moisture, the sea air, on entering an 

 Australian wood, has its temperature raised, and 

 becomes capable of licking up any drop of humidity 

 it may find still lingering there. For this reason, a 

 current of air is seldom perceptible in an Australian 

 forest, which always feels hot, dry and oppressive. 

 The immediate neighbourhood of Cape York indeed 

 seemed one of the comparatively favoured spots, 

 where frequent showers during the whole year per- 

 mitted the existence of permanent fresh water pools 

 and green grass during even the driest season. 



Whether or not the differences in the vegetation 

 and the climate of the neighbouring parts of the two 

 countries can be in any way dependent on each 

 other, it is evident that no alteration of temperature 

 or other conditions can have place in the sea, suffi- 

 cient to account for the change that takes place in 

 its inhabitants. It will be seen, however, in the 

 next chapter, that one of the corollaries deducible 

 from a speculation regarding the origin of the coral 

 reefs, is the probability of the assemblage in Torres 

 Strait of two groups of marine animals arriving from 

 opposite directions. 



June % 1845. — The Prince George had been 

 despatched to Booby Island for intelligence, and we 

 this morning weighed and followed her, bidding a 



