what now
gives to the steam-engine a rate entirely free from jerks. That is the
reason why it can, with equal success, embroider muslins and forge
anchors, weave the most delicate webs and communicate a rapid movement
to the heavy stones of a flour-mill. This also explains how Watt had
said, fearless of being reproached for exaggeration, that to prevent the
comings and goings of servants, he would be served, he would have gruel
brought to him, in case of illness, by tables connected with his
steam-engine. I am aware it is supposed by the generality of people that
this suavity of motion is obtained only by a loss of power; but it is an
error, a gross error: the saying, "much noise and little work," is true,
not only in the moral world, but is also an axiom in mechanics.

A few words more and we shall reach the end of our technical details.
Within these few years great advantage has been found in not allowing a
free access of steam from the boiler into the cylinder, during the whole
time of each oscillation of the engine. This communication is
interrupted, for example, when the piston has reached one-third of its
course. The two remaining thirds of the cylinder's length are then
traversed by virtue of the acquired velocity, and especially by the
detention of the steam. Watt had already indicated such an arrangement.
Some very good judges esteem the economical importance of the
steam-detent as equal to that of the condenser. It seems certain that
since its adoption the Cornwall engines give unhoped-for results; that
with one bushel of coal they equal the labor of twenty men during ten
hours. Let us keep in mind that in the coal districts a bushel of coal
only costs ninepence, and it will be demonstrated that over the greater
part of England Watt reduced the price of a man's day's work, a day of
ten hours' labor, to less than a sou (one halfpenny).

Numerical valuations make us appreciate so well the importance of his
inventions that I cannot resist the desire to present two more
improvements. I borrow them from one of the most celebrated
correspondents of the Academy--from Sir John Herschel.

The ascent of Mont Blanc, starting from the valley of Chamounix, is
justly considered as the hardest work that a man can accomplish in two
days. Thus the maximum mechanical work of which we are capable in twice
twenty-four hours is measured by transporting the weight of our body to
the elevation of Mont Blanc. This work or its equiv