1878.] ; 701 
[Chase, 
length M. .166; of the head, .035 ; to origin of ventral fin, .063 ; of anal 
fin .090 ; of second dorsal fin, .096 ; of caudal fin, .141. 
Besides the generic characters mentioned, this species differs from the 
Protistius semotilus of the same region, in the larger number of soft rays, the 
smaller eye, narrower interorbital space, ete. The lateral line is better de- 
fined in this species, but isnot continued beyond the anal fin; a few iso- 
lated tubes occur on scales on other parts of the sides. 
The color of the Gastropterus archwus is silvery, darker shaded on the 
upper surfaces, and without spots on the body or fins. 
Two specimens ; coll. of 1874; obtained by Prof. Orton, at Arequipa on. 
the Pacific slope at an elevation of 7500 feet. 
Radiation and Rotation. 
By Purny Earue Cuassz, LL.D., 
PROFESSOR OF PHILOSOPHY IN HAVERFORD COLLEGE. 
(Read before the American Philosophical Society, June 21, 1878.) 
Among the most interesting of the unsolved astronomical problems, are 
the questions as to the origin of solar radiation and of cosmical rotation. 
These two problems, as I have already shown, are intimately connected, 
at the centre of our system, by the ultimate equality which exists between 
the velocity of light, the limiting centrifugal velocity of solar rotation, and 
the velocity of complete solar dissociation. 
It has been commonly assumed that physical forses tend to ultimate equi- 
librium and consequent complete stagnation. The imperfections of any 
plan which looks to such a final result, have led some writers to suppose 
that there may be some compensating provisions, hitherto undiscovered, for 
a renewal of activity. In the search for such provisions, the equality of: 
action and reaction and the possibility that the compensation is continually 
furnished, by Him who is ever ‘‘upholding all things by the word of His 
power,’’ seem to have been wholly overlooked. 
If we assume the existence of a luminiferous ether, whether as a reality, or 
as a convenient representative of co-ordinated central forces, its undulations, 
when obstructed by inert centres, would necessarily lead tosuch phenomena 
as those of gravitation, light, heat, electricity, magnetism, etc. Confining 
ourselves for the present to the action of gravitation, it is well known that 
the limiting velocity of possible gravitating action and consequent cen- 
trifugal reaction, at any given point, i842 gr, the velocity varying as —— 
r 
If, according to the hypothesis of Mossotti, each particle is provided with a 
