mapped a larger extent of territory than any other of the numerous
surveyors employed on the work. There are yet in the archives of Sweden
detailed maps of upwards of fifty square miles made by his hand.

Neither the great labors attending these surveys, nor his military
duties, could give sufficient employment to the energies of the young
officer. In connection with a German engineer, Major Pentz, he now
began the arduous task of compiling a work on Canals, to be illustrated
by sixty-four large plates, representing the various buildings,
machines, and instruments connected with the construction of such
works. The part assigned to him in this enterprise was nothing less
than that of making all the drawings, as well as of engraving the
numerous plates; and as all the plates were to be executed in the style
of what is called machine-engraving, he undertook to construct a
machine for the purpose, which he successfully accomplished. This work
he prosecuted with so much industry, in the midst of his other various
labors, that, within the first year of its commencement, he had
executed eighteen large plates, which were pronounced by judges of
machine-engraving to be of superior merit.

While thus variously occupied, being on a visit to the house of his
Colonel, Ericsson on one occasion showed his host, by a very simple
experiment, how readily mechanical power may be produced, independently
of steam, by condensing flame. His friend was much struck by the beauty
and simplicity of the experiment, and prevailed upon Ericsson to give
more attention to a principle which he considered highly important. The
young officer accordingly made sonic experiments on an enlarged scale,
and succeeded in the production of a motive power equal to that of a
steam-engine of ten-horse power. So satisfactory was the result, from
the compact form of the machine employed, as well as the comparatively