’ J. R. Mayer on Celestial Dynamics. 407 
ingly subtract the vis viva of the axial rotation from the whole 
effect of the collision and mechanical combination, in order to 
obtain the quantity of heat generated. The rotatory effect, how- 
ever, is only a small quantity in comparison with the interior heat 
of the earth. It amounts to about 4400xT kilogrammetres, (T 
being the weight of the earth in kilograms) which is equivalent 
: units of heat, if we assume the density of the earth 
sequence of the action of a resisting medium, or from some other 
raised some thousands of degrees in temperature, and conse- 
quently the surface of the earth would be converted into a fiery 
ocean. At the same time, the velocity of the earth’s axial rota- 
tion would be somewhat accelerated, and the position of its axis 
with regard to the heavens, and to its own surface, slightly al- 
tered. If the earth had been a cold body without axial rota- 
tion, the process of its combining with the moon would have im 
parted to it both heat and rotation. Sen a 
It is probable that such processes of combination between dif- 
ferent parts of our globe may have repeatedly happened before 
the earth attained its present magnitude, and that luxuriant 
vegetation may have at different times been buried under the 
fiery debris resulting from the conflict of these masses. 
creasi per t 
earth’s crust, must have caused frequent disturbances and revo- 
lutions on its surface, accompanie gh 
Masses and the formation of protuberances; on the other han 
tation are closely connected, it is clear that the youth o our 
planet must have been distinguished by continual violent trans- 
formations of its crust, and a perceptible acceleration of the ve- 
