ON RAIL ROADS.

183

mechanical force required to move the bodyforward, at different velocities, will be asfollows :—

III.

Velocities - 1

Spaces - - 1

Times - - - 1

Resistance - 1

Mechanical force required, ) jacting for the above time VMechanical force required, ) jfor any given distance j

I would not have been thus particular in myelucidation of the effects of friction, had I notfound that considerable ambiguity existed onthe amount of resistance at different velocities.—I trust the foregoing explanation, if it donot dispel the ambiguity, will at least makethe reader acquainted with the sense in which1 shall hereafter use it in the work.

2 3 4

l l ll l 14 9 16

8 27 644 9 16

Experiments made at Killingsworth Colliery,zoith the dynamometer, to ascertain the frictionor resistance of carriages moved along Rail­ roads .

The rails were of cast-iron. Edge-rails ofMessrs. Losh and Stephenson’s plan, Fig. I.