er's _Journal_, and I send it to
you, hoping that you will have it engraved and perpetuated in your
valuable paper. It is a peculiar combination of Savery's invention and
Papin's piston engine, suggested for another purpose, and is a decided
improvement on Huyghens' powder engine.

[Illustration: PAPIN'S STEAM ENGINE.]

A is the boiler for the generation of the steam, provided with a
safety valve (an invention of Papin). On opening the stopcock, C, the
steam passes through B into the cylinder, D, and by its expansion
drives the plunger, E, against the water contained in the cylinder, D,
which is thus forced into the chamber, F, compressing strongly the
air, which in turn expels the water through the pipe, G, to the height
desired. K is a funnel for the fresh supply of water, and at I and H
are valves opening upwards and downwards. After the condensation of
the steam in D, a renewed supply of water, through K, forces the
plunger, E, to the top of the cylinder, ready for the next action of
steam. The strokes of such a pump could not be frequent, and it would
not compare very favorably with the wonderful machinery exhibited in
Philadelphia last summer; but it contains the germ of the idea, and is
worthy of all honor. Having often seen it stated that Papin had
invented a steamboat, I resolved during a recent visit to Germany to
investigate the matter, and especially to search for the
correspondence between Papin and Leibnitz in the library at Hanover.
It will be borne in mind that two hundred years ago, on December 4,
1676, Leibnitz was appointed to take charge of the library in Hanover,
and that he remained in this position until his death in 1716. He
bequeathed his manuscripts to the library; and as he had the habit of
writing upon all manner of loose scraps of paper, it has cost much
labor to assort and classify them.

On making my application to the librarian to be permitted to see the
correspondence between Papin and Leibnitz, my request was at once
granted; and a table having been assigned me, I was able to examine
these precious relics at my leisure. I was also shown a copy of an
original treatise on the steam engine by Papin, which contained
numerous marginal notes by Leibnitz. In one place, Leibnitz criticized
Papin's method for condensing steam, and makes a drawing on the
margin, showing a piston and valve which he thought would be more
practical. It is somewhat remarkable that the Germans have not caused
a fa