AEROPLANES.                                 235
hour. The machine is made with its present great length so
as to give a man time to think ; its length makes it easies to
steer and to change its angle in the air. Its quantity of power
is so enormously great in proportion 10 its weight thai it will
quickly get its speed. It will rise in the air like a sea-gull if
the engine be :un at full speed while the machine is held fast
10 the track, and if it is then suddenly loosened and let go.
M. Maxim very judiciously refrained from furnishing
drawings or detailed descriptions of an apparatus which
was still in process of evolution, and which he might want
to modify as he proceeded in erection and trial. Indeed,
it is probable that he has varied considerably from the
various arrangements which he has patented from time to
time,* so that drawings and descriptions made from these
might be wide ot the mark.
The important, the vital feature, however, he recog-
nized to be the motor, and to perfecting this he gave his
first attention. In steam motors he seems to have accom-
plished wonderful results, hitherto quite unreached, and
in an article published in the Century Magazine for Octo-
ber, 1891, after describing and illustrating the experimen-
tal whirling machine with which he had gathered his pre-
liminary data, ,he gives the following account of what he
had accomplished up to that time with the motor :
I have come to the conclusion that the greatest amount of
force with the minimum amount of weight can be obtained
from a high-pressure compound steam engine, using « team tt
a pressure of from 200 lbs to 350 lbs. to the square inch, and
lately I have constructed two such engines, each weighing 300
lbs. These engines, when working under a pressure of 200
lbs. to the square inch, and with a piston speed of only 400 It.
per minute, develop in useful effect in push of screws over 100
horse power, the push of the screws collectively being over
1,000 lbs. By increasing the number of turns, and also the
steam pressure. I believe it will be possible to obtain from 200
horse power to 300 horse power from the same engines, and
with a piston speed no greater than 850 ft. per minute, t These
engines are made throughout of tempered steel, and are of
great strength and lightness. The new feature about my
motors, however, is the manner of generating steam. The
steam generator itself, without the casing about it, weighs only
350 lbs. ; the engine, generator, casing, pumps, cranks, screw-
shaft, and screws weigh 1,800 lbs., and the rest of tbe machine
as much more. With a supply of furl, water, and three men,
the weight will not be far from 5,000 lbs. As the foregoing
experiments have shown that the load may be 14 times the
push of the screw, it would appear that this machine ought to
carry a burden, including its own weight, of 14,000 lbs., thus
leaving   a   margin   of   9,000   lbs ,   provided  that   the   steam
* British patents Nos. 10,359 and 16,883, A'D* 1889 ; No. 19,228. a.d. 1891.
t The piston speed of an express locomotive is about 1,000 ft. per minute.