1882.J 
Pleading for a Geological Idea. 
! 4 I 
IV. PLEADING FOR A GEOLOGICAL IDEA. 
By 0 . Reichenbach.* 
Amendment to Laplace's Nebular Theory. 
t NEBULA with unconfined room for expansion has 
no high temperature. The generation of a stellar 
system requires centres, solid atoms, to begin with, 
which, by exchange of attraction and repulsion, assign limits 
to the nebula, and by concentration of matter and increase 
of empty space produce oscillations of temperature, regu- 
larity of motions, composition, decomposition, and trans- 
formation of atoms and molecules. The beginning of a 
solar system is therefore not the concentration of a sun 
within detaching rings rolling up to planets, but the opposi- 
tion of solar and planetary centres, round which matter gets 
grouped into rings divided by more or less empty spaces, 
and into strata separated by nodal bands. 
A nebula must be either a collection of smallest spaces 
growing force from nothing, or a collection of such spaces 
set free by the collapse and death of such systems productive 
of heat, of high molecular centrifugality, of decomposition 
of mass, and of compound and simple molecules and atoms. 
Such a nebula, with re-incipient evolution, will produce heat 
and light by again passing into condensation, transformation, 
and combining motions. 
Spectral analysis therefore confirms that the more diffuse 
and without centres a nebula appears, the more backward it 
is in evolution, the more primitive are the substances com- 
posing it, and the less is its volume of motion, the volume 
described by its translatory motion in space, and the velocity 
of such motion. 
Generation of a Solar System. 
A solar system is engendered by the acftion of two or 
more systems on nebula in its nascent state. The planetary 
mass of our system, opposed to the solar mass, became 
* As contained in “ Some Properties of the Earth,” by O. Reichenbach, 
published by Wertheimer and Lea, Finsbury Plgce. 
