On the Law of Rotation of the Primary Planet. 397 
The great discrepancies, however, in Prof. L.’s estimates result 
in part from his assuming a period of twenty-seven hours as the 
time of rotation of “the asteroid planet.” His authority for this 
| assumption is the fact that Schreeter from some of his ae 
i supposed Juno to complete a revolution in that time. If we 
mit the correctness of Schreeter’s inference (which is doubtfal), 
it can afford no evidence whatever, that the original planet re- 
volved in the same or nearly the same — 
In regard to the values of the constant —;, for Mars and Jupi- 
D: 
ter, it is sufficient to say that by using the received masses of these 
bodies, and certain values of the mass, distance and time of ro- 
tation of the intervening planet, involving no absurdity, they per- 
fectly harmonize with the law of rotation. In the case of Saturn 
there is no discrepancy worthy of noti 
The objection drawn from the poate observed in the plan- 
etary system may be stated as follows: The eight principle pri- 
mary planets consist of two distinct classes : the ‘members of each 
exhibiting “a strong family likeness.” Uranus is included in the 
same class with Jupiter and Saturn; hence the probability that 
his period of rotation does not differ very much from theirs. The 
class of minor planets includes Mercury, Venus, the Earth and 
Mars. Of these the periods of rotation are nearly the same; va- 
rying between 23h. 2Um. and 24h. 40m. Now “if we suppose 
the asteroids to have been once united in a single body, probably 
no one would hesitate to assign it” to the last of these classes. 
The argument here urged against the truth of my law, is, that 
it makes the period of foinig of the original body between 
Mars and Jupiter, as well as that of Uranus, entirely different 
from those of all the dete whose rotary velocity as been as- 
certained. It is a remarkable fact, however, that in other respects 
geal iad peculiarities in the primitive constitution of those 
o bodies unquestionably obtained. I refer to the unknown 
a which produced the avulsion of the ancient gt and 
the anomalous motions of the satellites ee Uranus. 
_ Prof. L.’s discrepancy in the values of "for Venus and the 
nD? 
ae Farth results in part from his employing Encke’s mass of Mercu- 
ry, confessedly only an approximation. The mass adopted by 
rof. Walker is ip. mean of this value and the first and second 
masses of Leverr 
With regard, thee: to the wn/:nown mass and period of is hy- 
*Pothetical alsnpk and the rotation of Uranus, discussion would 
oak to useless, That my formula harmonizes with the known 
elements of the solar system as exactly as even recent determina~ 
tions of the masses of pee by different astronomers agree 
ee 5 
