t, while four others of older
type have been somewhat modernized, and there are three monitors
building at the present time. It may be doubted, however, if they will
be followed by others, at least so long as the conditions of naval
warfare and the spirit of public policy remain as they now are.

The monitor type was a perfect solution of the problem of its day, and
nobly it answered the calls made on it. The problem has now changed, the
conditions affecting its solution have also changed, and it is no
discredit to the original type that it now seems to have had its day,
and that it must give way to other forms more perfectly expressing the
spirit of the present age, and the means available for the solution of
present-day problems in the art of naval war.

In many ways, however, the influence of Ericsson's work still lives in
the modern battleship, and while in our modern designs we have gotten
far away from the essential features of the monitor type, yet it is not
too much to say that the germ of the modern battleship is in many ways
found in the "Monitor," especially as expressed in terms of
concentration of heavy gun-fire and localized protection of gun
positions; and in more ways than may be suspected, the influence of
Ericsson and of his work had its part in the developments which have led
to the splendid designs of the present day.

Returning again to our note of the dependence of the present age on
Ericsson, mention may be made of the blower for forcing the combustion
in steam-boilers as a well-established feature of standard marine
practice, and one absolutely essential to the development of the highest
attainable speeds, such as are required in warships, and especially in
those of the torpedo and modern "Destroyer" types. Likewise the use of
the fan for ventilation, as used by him in his early practice, has
become a necessity of modern conditions both on naval and passenger
ships, for the health and comfort of both passengers and crew. His long
series of experiments and his years of labor on air and other forms of
"caloric" engine are only represented by the "Ericsson air-engine" now
on the market, and having its fair share of service in locations where
simplicity of operation and scarcity of water may naturally suggest
its use.

Of his labors in connection with a solar engine, and with other
questions which occupied much of the time of his closing years, we have
but little direct result. Others are at work