Of clustered bodies in empty space, each will move along a line which is the resultant of the tractive forces exercised by all the rest, modified from moment to moment by the acquired motion; and the aggregation of such clustered bodies, if it eventually results at all, can result only from collision, dissipation, and the formation of a resisting medium.
"Essays: Scientific, Political, & Speculative, Vol. I"
Herbert Spencer
These platforms enable the tank to overcome all obstacles as the caterpillar tread is curved up in the arc of a huge circle at the front which gives the vehicle its wonderful tractive powers.
"Kelly Miller's History of the World War for Human Rights"
Kelly Miller
She was suddenly roused from her painful reverie by the pulling up of Helen's ponies, with much clatter and wriggling recoil, close beside her, making more fuss with their toy-carriage than the mightiest of tractive steeds with the chariot of pomp.
"Paul Faber, Surgeon"
George MacDonald