was engaged on the side of the Royalists in the Civil Wars of the
Revolution, lost his fortune and went to Ireland, where he was
imprisoned. Escaping to France, from thence he returned to London as a
secret agent of Charles II., but was detected and imprisoned in the
Tower, where he remained till the Restoration, when he was set at
liberty. One day, while in prison, he observed the lid of the pot in
which his dinner was being prepared lifted up by the vapour of the water
boiling inside. Reflecting on this, he turned his mind to the matter,
and thought that this vapour, if rightly applied, might be made a useful
moving power. He thus describes his invention in his 68th Article: "I
have contrived an admirable way to drive up water by fire, not by
drawing or sucking it upwards, thirty-two feet. But this way hath no
bounds, if the vessels be strong enough." He then goes on to say, that
"having a way to make his vessels, so that they are strengthened by the
force within, I have seen the water run like a constant stream forty
feet high. One vessel rarified by fire driveth forty of cold water, and
one being consumed, another begins to force, and refill with cold water,
and so on successively, the fire being kept constant. The engineman
having only to turn two cocks, so as to connect the steam with the one
or the other vessel."

In this engine, if it can be called an engine, we see that the Marquis
had a good idea of the power of steam, but he had none, you will
observe, as to the action of the condensation which would immediately
take place when the steam from the boiler was brought into contact with
the cold water to be raised. Therefore this plan would be most
expensive, on account of the great loss of steam by condensation. It
was, however, quite able to produce the effect, though only equal to
raising 20 cubic feet of water, or 1250 lbs., one foot high by one pound
of coal, or about the two-hundredth part of the effect of a good