ulation of his car, the stronger
becomes the desire to fly further and stay in the air longer than the
rest of his brethren. This necessitates larger, more powerful, and more
expensive machines as the work of the germ progresses.

Speed Affects Weight Capacity.

Don't overlook the fact that the greater speed you can attain the
smaller will be the surface area you can get along with. If a machine
with 500 square feet of sustaining surface, traveling at a speed of
40 miles an hour, will carry a weight of 1,200 pounds, we can cut the
sustaining surface in half and get along with 250 square feet, provided
a speed of 60 miles an hour can be obtained. At 100 miles an hour only
80 square feet of surface area would be required. In both instances the
weight sustaining capacity will remain the same as with the 500 square
feet of surface area--1,200 pounds.

One of these days some mathematical genius will figure out this problem
with exactitude and we will have a dependable table giving the maximum
carrying capacity of various surface areas at various stated speeds,
based on the dimensions of the advancing edges. At present it is largely
a matter of guesswork so far as making accurate computation goes.
Much depends upon the shape of the machine, and the amount of surface
offering resistance to the wind, etc.

CHAPTER IX. SELECTION OF THE MOTOR.

Motors for flying machines must be light in weight, of great strength,
productive of extreme speed, and positively dependable in action.
It matters little as to the particular form, or whether air or water
cooled, so long as the four features named are secured. There are at
least a dozen such motors or engines now in use. All are of the gasolene
type, and all possess in greater or lesser degree the desired qualities.
Some of these motors are:

Renault--8-cylinder, air-cooled; 50 horse power; weight 374 pounds.

Fiat--8-cylinder, air-cooled; 50 horse power; weight 150 pounds.

Farcot--8-cylinder, air-cooled; from 30 to 100 horse power, according to
bore of cylinders; weight of smallest, 84 pounds.

R. E. P.--10-cylinder, air-cooled; 150 horse power; weight 215 pounds.

Gnome--7 and 14 cylinders, revolving type, air-cooled; 50 and 100 horse
power; weight 150 and 300 pounds.

Darracq--2 to 14 cylinders, water cooled; 30 to 200 horse power; weight
of smallest 100 pounds.

Wright--4-cylinder, water-cooled; 25 horse power; weight 200 pounds.

Antoinette--8 and 16-cylinder, wat