J. R. Mayer on Celestial Dynamics. 187 
Art. XV.—On Celestial Dynamics; by Dr. J. R. MAYER. 
THE movements of celestial bodies in an absolute vacuum 
would be as uniform as those of a mathematical pendulum, 
whereas a resisting medium pervading all space would cause the 
planets to move in shorter and shorter orbits, and at last to fall 
into the sun. 
Assuming such a resisting medium, these wandering celestial 
bodies must have on the periphery of the solar system their 
cradle, and in its centre their grave; and however long the 
duration, and however great the number of their revolutions 
may be, as many masses will on the average in a certain time 
arrive at the sun as formerly in a like period of time came 
within his sphere of attraction. k 5 
‘All these bodies plunge with a violent impetus into their 
common grave. Since no cause exists without an effect, each of 
these cosmical masses will, like a weight falling to the earth, 
produce by its percussion an amount of heat proportional to its 
vis viva. 
From the idea of a sun whose attraction acts throughout 
Space, of ponderable bodies scattered throughout the universe, 
] 
Concerning subjects so distant from us in tim 
and confine our attention exclusively : 
m the observation of the existing state of things. 
_ Besides the fourteen known planets with their eighteen satel- 
lites, a great many other cosmical masses move within the space 
of the planetary system of whi h the comets deserve to be men- 
tioned first, 
: Kepler's celebrated statement that “there are more comets m 
| ? Continued from vol. xxxvi, p. 266. +“ 
