E2L6
Lemma — Part II
Latin
English (Elwes 1883)
If certain bodies composing an individual be compelled to change the motion, which they have in one direction, for motion in another direction, but in such a manner, that they be able to continue their motions and their mutual communication in the same relations as before, the individual will retain its own nature without any change of its actuality.
Modern English
If certain bodies composing an individual are forced to redirect the motion they had in one direction toward another direction, but in such a way that they can continue their motions and communicate them to one another in the same proportion as before, the individual will likewise retain its nature without any change of form.