las 
MINUTES OF PROCEEDINGS OF 
TRACTION. 
BY 
MAJOR W. KEMMIS, R.A. 
In a previous paper, “Principles of Construction of Wheels and 
Axles/"’ (“Proceedings, R.A. Institution,"” Yol. VIII. p. 369), the 
relations between the forces which act upon the wheel and axle when 
upon the point of motion have been stated as follows :— 
JF = half weight of axle and load, 
P = traction, or moving power, its direction making an angle /3 
with the horizontal, 
R = resultant of P and fF, its direction making an angle 0 with the 
vertical, 
W = weight of the wheel, 
R! = resultant of R and W' } its direction making an angle O’ with the 
vertical, 
(}> = limiting angle of resistance between the pipe-box and axletree- 
arm, 
y = angle of slope of the ground, 
AC — radius of the pipe-box, 
BC = radius of the wheel. 
Then 
P . cos F — R • sill 0, .. 
P . sin F + R . cos 6 = W 9 . 
R . sin 0 = R! . sin O', . 
R . cos 0 + W = R !. cos . 
. A AC' sin O' .sin 6 
sm 6 — pTg gin (g' — y) 
0 ) 
( 2 ) 
(3) 
(4) 
(5) 
Proceeding from these equations to obtain the value of P ; by com¬ 
bining (1) with (2), 
sin 0 = 
P . COS F 
Cm + P 3 - 2P . fiPTsin F 1 
( 1 ') 
