whole being enclosed with sheet-iron. The advantage of this arrangement
is obvious; for, while more than a sufficient quantity of steam is
generated for the purposes requited, the only possible accident that
could happen would be, the bursting of one of these barrels, and a
temporary diminution of the steam-power of one-fortieth part. The
effects of the accident could, of course, only be felt within its own
enclosure; and the Engineer could, in ten minutes, repair the injury, by
extracting the wounded barrel, and plugging up the holes at each end;
but the fact is, that such are the proofs to which these barrels are
subjected, before they are used, by the application of a steam-pressure
five hundred times more than can ever be required, that the accident,
trifling as it is, is scarcely possible.

A contemporary journal illustrates Mr. Gurney's invention by the
following analogy:--"It will appear not a little singular that
Mr. Gurney, who was educated a medical man, has actually made the
construction of the human body, and of animals in general, the model
of his invention. His reservoirs of steam and water, or rather
'_separators_,' as they are called, and which are seen at the end
of our plate, are, as it were, the heart of his steam apparatus, the
lower pipes of the boiler are the arteries, and the upper pipes the
veins. The water, which is the substitute for blood, is first sent from
the reservoirs into the pipes--the operation of fire soon produces
steam, which ascends through the pipes to the upper part of the
reservoir, carrying with it a portion of water into the separators,
which of course descends to the lower part, and returns to fill the
pipes which have been exhausted by the evaporation of the steam--the
steam above pressing it down with an elastic force, so as to keep the
arteries or pipes constantly full, and preserve a regular circulation.
In the centre of the _separators_ are perforated steam pipes, which