The conservation of energy. Balfour Stewart ... With an appendix treating of the vital and mental applications of the doctrine. Stewart, Balfour, 1828-1887. Force and energy. QC73 .S84 1874a 531.6 STC Series title also at head of t.-p. New York : D. Appleton and company, 1874. 1874. 1874 Text viii, 236 p. : eng The international scientific series. [American ed. v. 7]