* 
Pe crs gt gee ay ee 
J. H. Lane on the Theoretical Temperature of the Sun. 57 
ing which these underlying beds were formed, but there would 
seem to have been a restoration of this southern border of the 
drift-swept region at least, to dry land once more, and this res- 
toration must have continued through a period of considerable 
leneth. It was followed by another movement of depression, 
during which the highest of the yellow clays, the latest forma- 
tion of the drift, were deposited. There seem materials in this 
line of facts for a more orderly division of the later formed de- 
posits of the post-tertiary than has heretofore been recognized. 
We also learn that mammalian life was associated with this 
intercalated period of vegetable growth. The mammoth and 
the mastodon subsisted on the coniferous wood which is repre- 
sented so largely here. The series of changes in level already 
referred to, must haye exterminated these earlier representatives 
of elephantine life, but we find the same species returning to 
their old dwelling places when the waters of the drift seas had 
finally abated. 
Art. IX.— On the Theoretical Temperature of the Sun ; under 
the Hypothesis of a Gaseous Mass maintaining its Volume by tts 
Internal Heat, and depending on the Laws of Gases as known — 
to sg ya Experiment; by J. Homer Lane, Washing- 
ton, D. U. 
[Read before the National Academy of Sciences at the session of April 13-16, 1869.] 
MAny years have passed since the suggestion was thrown out 
by Helmholtz, and afterwards by others, that the present vol- 
ume of the sun is maintained by his internal heat, and may be- 
come less in time. Upon this hypothesis it was proposed to - 
account for the ‘renewal of the heat radiated from the sun, by 
means of the mechanical power of the sun’s mass descendi 
toward his center. Calculations made by Prof. Pierce, and 
ve shown that this provides a supply of 
~ 
astronomical facts. Some years ago the question occurred to me 
in connection with this theory of Helmholtz whether the entire 
and whether Hersche 
