Actions of Volcanoes. 291 
losophy to omit all consideration of final causes, I might here 
point out the singular and beautiful arrangement thus made 
for providing fresh water for the eventual inhabitants of islands, 
which, from their necessary want of springs, or other modes of 
supply, could never have become the residence of man; of the 
improvident being at least, whose lot it must be to commence 
the population of these new regions. 
The remainder of the operation is to clothe these islands with 
soil and vegetation. This is the work of time, yet itis more 
rapid than would be expected. The first foundation of it is laid 
by the sand which the sea produces from the destruction of the 
corals, and by the sea plants which take root and grow upon it. 
Sea birds, finding a place to settle in, add something; and at 
length the seeds of various plants floating about the ocean are 
arrested and begin to grow, when a vegetable covering succeeds. 
Among these plants, the most conspicuous are the Sczvola, 
Pandanus, Cerbera, Morinda, Hernandia, and others, which 
first begin to grow in the outer bank, where their seeds were 
originally arrested, and at length spread over the whole. Last 
of all comes Man, and the island forms a part of the inhabited 
world. 
It is evident, that islands formed on this principle, can have 
no great elevation above the water; and accordingly, those 
which are entirely flat, are scarcely elevated more than five or 
six feet above the high-water mark. But as many of them are 
higher, it is necessary to resort to some new principle for effect- 
ing this purpose. This principle is that action of a subterraneous 
elevating force, which forms the main object of this communica~ 
tion ; and by means of which the phenomena of the coral islands 
become connected with those of the Italian alluvia. 
Tongataboo, already mentioned, is ten feet above the high- 
water mark; which is a greater elevation than can be produced 
by the action of the sea, supposing that the whole of that space 
consisted of fragments such as have been described, and not of 
perfect corals, which cannot raise themselves to the least dis~ 
tance above the sea. But Captain Cook observed in many 
islands, that the corals, with all their characters as perfect as 
U2 
