A dissertation on the influence of gravitation considered as a mechanic power : explaining the reason why the effective power of the same quantity of matter, in descending the same height, is twice as great in its uniform descent, as in its accelerated fall /
Cumming, Alexander.
London :  printed by J. & E. Hodson, sold by G. & W. Nicol, 
1802.
A microfilm of the British Library copy.
Gravitation.