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Prof. Loomis on the Satellites of Uranus. 405 
Arr. XXXVIIL—On the Satellites of Uranus; by Enaas 
Loomis, Professor of Mathematics and Natural Philosophy in 
the University of the city of New York. 
Uranus was discovered to be a planet by Sir William Herschel 
in 1781; and in 1787 he discovered two satellites whose periods 
were satisfactorily determined by his subsequent observations. 
In 1797 he announced the discovery of four additional satellites, 
viz., one within the orbits of both the former two; one interme- 
diate between the two; and two exterior to both of them, but the 
periods of these satellites he acknowledged to be very uncertain. 
In his lgst paper on this subject communicated to the Royal So- 
ciety in 1815, he says, “that there are additional satellites besides 
the two principal large ones, I can have no doubt; but to deter- 
mine their number and situation, will probably require an increase 
of illuminating power in our telescopes.” ee 
In 1834, Sir John Herschel published a paper contaming a 
thorough discussion of his father’s observations, together with his 
own, upon the two satellites first discovered ; and he adds, “ of 
other satellites than these two I have no evidence.” 
In the year 1838, Dr. Lamont of Munich published a few ob- 
servations of the two brighter satellites of Uranus, and stated that 
he had seen only one additional satellite and that in but a single 
instance. This satellite he considered to be the most remote of 
At last in the autumn of 1947, Mr. Lassell of Liverpool and M. 
Struve at Pulkova, obtained unequivocal evidence of the exist- 
ence of a third satellite. The orbit of this satellite was evidently 
smaller than that of either of the two bright ones; yet the pee 
indicated by Lassell’s observations did not agree with a 2 
duced by Struve; and both differed from the interior satel aa 
Sir William Herschel. While Lassell’s observations indicated a 
period of about two days, Struve deduced from his “a sopeagiey 
@ period of four days; and the oe assigned by Herschel to his 
interior satellite was nearly six days. he qt 
involved in total contasive) and the honest inquirer might 
be puzzled to decide whether there existed three satellites, or only 
Ohe, interior to the two brighter ones. 
i 
oT 
Stcony Spies, Vol. XIV, No. 42.—Nov., 1552. 52 
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