198 Scientific Intelligence. 
the water-wheels ; but the water-wheels themselves are capable of 
being taken to pieces, and removed in bad weather, all except- 
ing two principal arms of each, which being of cast-metal, and 
securely fastened, are placed in a horizontal position in high 
seas, and are productive of little inconvenience. What renders 
this experiment unfavourable to the application of steam to ves- 
sels trading to distant countries, is the immense consumption of 
coals, and the occupation of the whole of the stowage in the hold 
by tlie requisite coals and machinery. Hence there is no room 
left in the vessel but the ’tween-decks, for the cargo. Besides, 
the expence of coals only, which amounts to ten tons per day, 
(omitting the value of the machinery, and the loss of stowage), 
is more than proportionate to the advantage gained in the pas- 
sage. The engine is of little service, excepting in moderate or 
in calm weather. In a fresh breeze, when favourable, a suffi- 
cient velocity is obtained without it; >and when unfavourable, it 
is incapable of driving the ship against the wind. 
It seems probable, therefore, that for general purposes, steam 
will not be found applicable as a power for propelling ships 
across extensive seas ; being principally confined in its use to ves- 
sels carrying passengers. 
49 . Plants impregnated with Carbonate of Lime mistaken for 
Coral . — Captains Vancouver and Flinders, and M. Peron, ob- 
served on the shores of New Holland, at considerable heights 
above the level of the sea, arborescent calcareous productions, 
which appeared to them to be altered organic bodies. Vancou- 
ver and Flinders considered them as corals, and from their oc- 
curring high above the present level of the sea, around New 
Holland, inferred that the level of the ocean must have sunk. 
Peron says they are either corals, or vegetables incrusted with 
calcareous matter. Mr Clarke Abel m^et with similar appearan- 
ces near Simon’s Town, at the Cape of Good Hope, and has pro- 
ved that these arborescent coral-like bodies are not coral, but 
vegetables impregnated with carbonate of lime. We recommend 
the perusal of Mr Abel’s account, from page 308. to page 312. 
of his “ Narrative of a Journey in the Interior of China,” to 
our readers. 
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