310 On the Energy expended in Propelling a Bicycle. 
In the other series of experiments made in July, 1882, a spring was placed 
directly under the treadle so that its compression was proportional to the vertical 
component of the force exerted by the foot. It moved the pencil horizontally by a 
bell-crank lever while the paper was carried up and down by a secondary crank 
fastened to the end of the crank of the bycicle. Thus the distances in one direc- 
tion 02 the indicator diagrams represent the vertical force of the foot, and distances 
at right angles represent the vertical heights of the end of the bycicle crank. The 
apparatus is represented in Figure 6, Pl. 40, the diagram it produces in Figure 7, 
Pl. 41, and the reduced indicator diagram in Figure 8, Pl. 41. The reduction was 
effected as before by the help of Figure 5, Pi. 40. It will be observed from the 
position of the rider, and since the vertical component of the foot’s pressure is 
what is registered, that the results furnished by this method cannot eaceed the 
truth. They are as follows, No. 29 of the series being that represented in Figure 7, 
Pl. 41. That the results of this series are so close to those of Table I. shows that 
both must be near the truth. 
“ee 
TABLE II. 
Serres IT. of Observations made in Summer with the Recording Spring attached to the Treadle. 
No. of accemaner Wyerey ve Velocity |} Coefficient 
Experi-| ~~ Mile I Rees a in Miles of Observations. 
ment. ¥ tet per Hour. | Resistances. 
17 16,000 1,850 7 ox Observations on dry hard gravelled path in Pal- 
18 20,500 3,600 10-4 st merston-park, down a trifling inclination of 1 
19 47,000 10,400 13:3 ahs in 160 ; calm. 
20 18,000 2,000 6-7 siz 
21 25,600 4,700 11-3 ar Up the same incline ; calm. 
22 45,000 10,400 14 aes 
23 36,000 6,000 10 wy Down the incline when wet ; calm. 
r On dry level road in Palmerston-park ; calm. 
ae Ae a a 4 Bo The road was in good order for roads in that 
° = ? 32) neighbourhood. 
26 24,300 3,300 8:2 qs 
27 28,000 4,600 9 37 On the same road, in the direction of a light wind. 
28 47,000 10,400 13-4 EF 
29 36,000 5,350 9 zo 
30 38,400 5,500 86 or On the same road, against light wind. 
31 51,200 9,000 10-4 sez 
= 33,000 5,100 9 as Average of the preceding experiments. 
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