Observations on Inclined Planes. 11t 
* Experiment 2d, on friction.—Length of plane 1164 feet; per- 
fectly straight, with a uniform and regular descent of 1 yard in 104.24; 
edge rail of Losh and Stevenson’s patent, 24 inches broad. at top. 
The carriages were allowed to descend freely. by their gravitating 
force, and the space they passed over ascertained by a stop watch, 
_ Four loaded carriages, each weighing 9408 lbs. descended ts the plane 
in 120 seconds,” The value of x in equation A, from these data, 
is .15, and f=42.79 lbs. for the resistance of friction of each car- 
riage, being nearly the 220th part of the weight. By Mr. Wood’s 
formula, we have, in this case, f=39.35 lbs. The difference in re- 
sults may be caused by the resistance of inertia not being included’ 
in the latter value of f. 
“* Experiment 19th.—Upon the Killingworth rail road: self-acting 
plane, with a rope-roll, round which the rope winds, one end of 
which is attached to the descending, the other to the ascending car- 
riages; length of plane 715 yards, descent 574 feet. Six loaded- 
carriages, each weighing 8764 lbs. descended by their gravitating 
force, and drew up seven empty carriages, each weighing 2800 Ibs. — 
on a mean of several times, in 180 seconds; weight of the r 
Ibs.; weight of the sheaves 3297 Ibs.; weight of the rope-roll 4686 
lbs. ‘The descent of this plane is not regular, being greater at the 
top than at the bottom, the line of the road perfectly straight.” Ta- 
king, in this case, f= the 200th part of the weight, we find F’, from 
equation D, equal to 212 Ibs. Mr. Wood gives, in this instance, 
F=204 lbs. 
““ Example.—Suppose a descending plane, the length of while is 
1800 yards, down whieh it is intended to pass 9 loaded carriages at 
a each weighing 4 tons, which drag up 9 empty carriages, each 
24 cwt.; ired the height of the plane, or inclination, - 
shal will cause the descent in 400 seconds. Weight of rope 5562. 
lbs.; weight of the sheaves 5400 Ibs.; rope-roll 454 Ibs.” In this 
case, taking f= the 200th part of the weight of the carriages, and 
1099 
F=,,(¢+m+p+~—-) = 228-4 
1099 d swe 
in equation D, $28} aT Beye 
is, the plane rises 1 in 513. The ines of Mr. Wood gives 1 in 
50; for the elevation of the plane. It should be observed, that ¢ has 
‘been taken equal to % of 400, a correction adopted by Mr. Wood, 
in order to manee: the descent within the required ere in alt states 
of the weather. 
2 we oP by substitution 
erat ds which gives n= 51%; that 
