311 
Mr. Hamilton, in making these observations on the influence 
of water in the formation of rocks, appears to have been under 
the impression that it was reviving the doctrine of W erner. This 
is a misconception of the modus ojperandi of the semi-aqueous 
action in the subterranean base, and shows that geologists, with 
all the advantages of modern discoveries and experiments in 
hydrothermal action, have not yet been able to comprehend 
the subject in its true light. The chemical or electro-magnetic 
wet process of crystallization, the production of metals from 
solutions, and the aggregation of crystals iuto large and 
compact massive rocks, must not be confounded with the old, 
crude mechanical theory, called the Aqueous,” introduced by 
Werner. It is as different from that, as the formation of a 
crystal is from that of a brick or a sediment. The one ope- 
rates by attraction and chemical action, and the other by 
mere mechanical deposition or precipitation. The former 
action produces the crystalline rocks, and causes their upward 
crystalline growth, and the latter produces the superincum- 
bent beds of deposits from substances held in suspension, and 
carried to lower levels by water. 
The Formation oe Corals. 
Before I went to South America, I had been taught to 
believe that corals were built by marine animalculse, in a 
way somewhat similar to the formation of the honeycomb by 
bees. 
I have had the opportunity of studying the growth of corals, 
in great variety and magnitude, on the shores of South 
America, the coast of the Isthmus of Panama, in some of the 
islands of the Pacific, in the Bed Sea, at Singapore, Ceylon, in 
the coral islands of the Indian Sea, and on the coast of Australia, 
but I never detected a single case of a coral being built by 
animalculse. I have seen, as it were, plantations of corals, cul- 
tivated for lime. I have seen their stems transplanted, and 
have watched their growth, both the mushroom and the 
arborescent form. The former appears to grow in the water 
like a fungus or sponge, and the latter has a growth and 
development like arborescent crystals, such as aragonite, &c. 
In fact, corals are not built up by insects, but are formed and 
grow’ like vegetation, having a beautiful internal structure, 
like the fibres, rings, and medullary rays of the trunks of 
coniferoe, &c. There are siliceous as well as calcareous plants 
found growing in the sea, but I shall not on this occasion 
dwell longer on these formations. My object in thus noticing 
