186 Review of Recent Geological Literature. 
remains only an aching void for a new one, which it would be unkind 
to withhold, since the material is so abundant, being in most cases 
'such stuff as dreams are made of,' and yet in our day dreams we 
sometimes catch glimpses of thoughts that lead us into the very pres- 
ence of truth." 
The new theory of the author starts with a further postulate, viz: 
light and heat are essential elements of the universe, and their exist- 
ence is not to be explained nor called in question. They are converti- 
ble into all other forms of energy, but they cannot be lost. They can- 
not wander beyond the confines of the universe, for this is boundless. 
The real problem is, How are the light and heat given out by the sun, or 
an equivalent for the same, reconcentrated in that luminary? 
Briefly stated the author's theory assumes heat as the primal, un- 
specialized, essential condition of universal matter, matter also unspec- 
ialized and nebular. All other forms of energy are modified conditions 
of heat. Heat is converted into light, motions of various kinds, chemical 
aflBnity, electricity, and even vital energy^ Heat as such is constantly 
dying out, but it dies as the seed does on being committed to the ground, 
to reappear in new and wonderful forms. Heat that leaves the sun, and 
without doubt also other suns that inhabit space, traveling on the vi- 
brations of the all-embracing ether, cannot dwindle into non-existence 
because if it did the grandest discovery of modern times, the conser- 
vation of force, disappears with it. What becomes of it? The author 
conceives of it as lurking as other forms of force in every part of the 
universe, changed by circumstances sometimes to mechanical force 
(or gravitation), stored up in chemical compounds, or developed into 
electricity, magnetism, or vital energy. It is thus not lost. It returns 
to the sun specialized as mechanical force, electricity, etc. "He sends 
it forth again in the general unsifted form of radiant light and heat." 
The etheral ocean is full of the undulations of heat, or the elements of 
heat, passing in all directions from sun to planet and to distant suns. 
The suns supply the ether, and the ether supplies the suns. "Since 
the dawn of creation heat has been undergoing ti'ansformations and 
retransformations, but neither annihilation nor re-creation." It is 
diffused in all directions, as well toward the suns as from them. 
[to be continued.] 
Lts geologues et la geologic du Jura, ju»qu''(n 1870. Par Jules Mar- 
cou. (Ext. des Mem. de la Soc. d'Emulation du Jura, 1S89. These 
memoirs, comprising only the creative period of the geology of the Ju" 
ra, extend only to the year 1870. They detail some of the personal 
labors and intercourse of M. Marcou with Dr. Germain, Pidancet, Thur- 
mann, Pictet, Dr. William Roux, Agassix, Fraas, Lory and others; 
specifying the various advances in the knowledge of the Jura wrought 
out by their joint labor. It also contains a chronologic review of the 
earliest geological work on the same, beginning with that of Charbaut 
in 1818. 
First report on the Iron mines and Iron ore districts in the state of New 
