TRAVELING AT HIGH SPEEDS—HELE-SHAW. 635 
by that of steam and the other forces of nature, the origin of the 
wheel being absolutely lost in antiquity. 
From the models which I now show will be noticed the way in 
which the wheel acts and how it overcomes the defect of animal 
locomotion, giving a rotary and continuous movement instead of a 
reciprocating and variable one. At one and the same time the wheel, 
therefore, does away with the three causes of loss shown in the 
diagram as occurring with animal locomotion. The mere use of the 
wheel has enabled man himself, by his own muscular effort, enor- 
mously to increase his individual power of locomotion. The top 
curve on figure 2 shows, in comparison with the other curves of 
walking and running, his unpaced records on a bicycle, in using 
which it will be realized that all three causes of loss which occur in 
running and walking are obviated. You will notice a similar differ- 
ence in speed as the distance varies to that which is made evident in 
the curves for walking and running. For the distance of 100 miles 
the average speed is thus only 21 miles an hour, while that for a one- 
fourth mile is more than 35 miles an hour. In view of the results 
shown by the curve, it is not surprising that the bicycle has entered 
largely into the conditions of modern life. Iam not able to give you 
any exact figures of the quantity of bicycles turned out each year in 
this country,-but I can tell you that in the post office alone there are 
now 12,000 bicycles employed, and their number is always on the 
- increase; the distance covered on them by men and boys in the year 
is more than 120,000,000 miles. 
I have not dealt with paced bicycle records, as such are not the 
result of muscular effort, but of being pushed along by the current 
of wind which follows up the pacing machine, such as occurs when a 
man on a “‘push”’ bicycle is paced by a motor vehicle. Ina record 
first set up in America for 60 miles an hour on a bicycle, a man was 
paced by a locomotive engine, running at 60 miles an hour along a 
special track; the rider was nearly killed when he tried to drop 
‘behind, owing to the whirlwind which was being dragged along by 
the engine; ultimately his life was saved by his being lifted bodily 
off his bicycle onto the locomotive. There is no record as to what 
became of the bicycle. 
Curiously enough, records for ice skating and roller skating are 
almost the same, and far below that on the bicycle, which I think 
proves distinctly that the reciprocating movement of the limbs limits 
man’s powers, whether he is sliding on the ice or using wheels as with 
roller skates. This is so, notwithstanding that he carries along 
with him when on a bicycle the extra weight of the bicycle, but the 
reciprocating movement of his legs is so slow, owing to the gearing 
up of the driving wheel, as to give him the material advantage shown 
by the respective curves. Further, in skating, there is no doubt that 
