274, Mr. J. S. Stuart Glennie on the 
their orbits by the disturbances of the external satellites. The 
increased temperature originating from this cause, must not only 
permit the existence of fluids im the extensive fields of floating 
matter, but also maintain an atmospheric covering of vapour, to 
give more continuity and symmetry to the annular appendage. 
If the physical characters of Saturn’s rmgs be such as matter, 
not having an improbably great density, must necessarily assume 
in the region which they occupy, the independent movements of 
its parts may be regarded as a continual source of heat, which 
may perhaps in some degree mitigate the sway of intolerable 
cold in the frigid zone of the solar system. 
Cincinnati, Feb. 19, 1861. 
XLIII. On the Principles of Energetics.—Part I. Ordinary Me- 
chanics. By J. 8. Stuart Guenniz, M.A., F.R.AS* 
his | fee the introductory paper, “On the Principles of the 
Science of Motion,” I suggested that this name might 
be given to a new general science, rankmg with the similar 
science of Growth, and not be used merely as a general name for 
the sciences of Ordinary + Mechanics (Stereatics and Hydraties) 
and Molecular Mechanics (Physics and Chemics{). The science 
of Motion would, as a distinct science, or as a philosophy of the 
Mechanical Sciences, consider, first, the relations of motions, as 
motion, and without reference to their originating or determi- 
ning causes or forces; and secondly, the conditions, and corre- 
lations of the conditions, of Pressure, bodily, or molecular, to 
which modern experiment and analysis give us the hope of being 
able to refer all the forces of motion. ‘To the former section of 
General Mechanics I would give the name, coined or made cur- 
rent by Ampére, Kinematics§; for the latter section I would 
adopt the term Energetics ||,already introduced by Rankine witha 
similar meaning to that given by the above statement of its object. 
2. It is proposed in the following papers partially to develope 
the conceptions of the introductory paper, by stating the funda- 
mental principles of the proposed Science of Energetics, with 
their applications to the mechanical interpretation of phenomena. 
The justification and development of these principles is the work 
of the sciences of Mechanics, Physics, and Chemics respectively. 
3. The science of Energetics may be defined as the theory of 
* Communicated by the Author. 
+ Would there not be a more definite distinction between the two 
branches of Mechanics by means of the adjectives Corporal and Molecular? 
{ Phil. Mag. January 1861, p. 54. 
§ Essai sur la Philosophie des Sciences. 
|| “A science whose subjects are material bodies, and physical pheno- 
mena in general,” Edinb. Phil. Journ. N. S. ii, 1855, p. 125. 
