Moving Force. 19} 
spent in producing change of figure in non- 
elastic bodies, can ever be restored. 
_I believe Mr. Smeaton was. the first who 
subjected to actual admeasurement. the force 
spent in producing change of figure in the 
collision of non-elastic bodies.* He appears to 
have been led to this investigation, not by 
curiosity merely, but by a conviction of the 
insufficiency of the prevailing doctrines of 
forces to account for the facts which were _ 
constantly presented to him in. his ordinary 
occupations, and particularly, as I have before 
observed, in the action of water on water 
wheels. It is very remarkable, that while 
Mr. Smeaton’s other dissertations . on. the 
principles of moving force, haye met with 
considerable attention abroad as well as at 
home, this last treatise on the collision of 
bodies, (which he himself considered a most 
important one, as containing the best confir- 
mation of his former conclusions) has been. 
almost totally neglected by all succeeding 
writers. It is impossible for me to. do justice 
to it by giving an abstract of it; but I would 
earnestly recommend the entire treatise to the 
attention of all those who.take an interest in 
investigations of this kind. 
«With regard to the collision of bodies. which 
are supposed to be perfectly hard as well as 
an # Philos. Trans. 1782, 
