on the idea of the solar
engine, and it may be that a practicable solution of the problem will
be found.

Ericsson's lasting imprint on engineering practice, curious as it may
seem, was made in his earlier and middle life, rather than in his later
years, and we have even more in the way of permanent acquisition from
his earlier than from his middle years. This results from the fact that
in middle life he was largely engaged on warship designs, admirably
adapted to the needs of the time and to the possibilities of the age,
but no longer suited to either, while in later life he no longer found
it necessary to work at problems which would produce a direct financial
return, and therefore interested himself in a variety of questions
somewhat farther removed from the walks of every-day engineering
practice than those with which he was occupied in earlier life.

In personality Ericsson possessed the most pronounced and self-centred
characteristics. Professionally he felt that to him had been granted a
larger measure of insight than to others into the mysteries of nature as
expressed in the laws of mechanics, and he was therefore little disposed
to listen to the advice or criticism of those about him. This was
undoubtedly one of Ericsson's most pronounced professional faults. He
did not realize that with all his insight into the laws of mechanics and
all his capacity for applying these laws to the solution of the problems
under consideration, he might well make some use of the work of his
fellow-laborers in the same field. So little disposed was he to thus use
the work of others that a given device or idea which had been in
previous use was often rejected and search made for another, different
and original, even though it might involve only some relatively trivial
part of the work. He was simply unwilling to follow in the lead of
others. He must lead or have none of it, and thus the fact that a device
or expedient was in common use would furnish an argument against rather
than for its adoption. His natural mode of work was utterly to disregard
precedent and to seek for fundamental solutions of his problems, having
only in view the conditions to be fulfilled, the laws of mechanics, and
the engineering materials of construction. This habit of independence
and of seclusion within the narrow circle of his own work so grew upon
him in later years that mechanical science made many advances of which
he took little or no note, and of