e itself into three or
four,--that three or four spots would often unite themselves into
one,--and that all the spots revolved regularly with the sun, which
appeared to complete its revolution in about twenty-eight days.

[16] Professor Rigaud is of opinion that Galileo had discovered the
solar spots at an earlier period than eighteen months before May
1612.

Previous to the invention of the telescope, spots had been more than
once seen on the sun's disc with the unassisted eye. But even if these
were of the same character as those which Galileo and others observed,
we cannot consider them as anticipations of their discovery by the
telescope. As the telescope was now in the possession of several
astronomers, Galileo began to have many rivals in discovery; but
notwithstanding the claims of Harriot, Fabricius, and Scheiner, it is
now placed beyond the reach of doubt that he was the first discoverer of
the solar spots. From the communication which I received in 1822 from
the late Dr Robertson, of Oxford,[17] it appeared that Thomas Harriot
had observed the solar spots on the 8th of December 1610; but his
manuscripts, in Lord Egremont's possession,[18] incontestably prove that
his regular observations on the spots did not commence till December 1,
1611, although he had seen the spots at the date above mentioned, and
that they were continued till the 18th of January 1613. The
observations which he has recorded are 199 in number, and the accounts
of them are accompanied with rough drawings representing the number,
position, and magnitude of the spots.[19] In the observation of Harriot,
made on the 8th December 1610, before he knew of Galileo's discovery, he
saw three spots on the sun, which he has represented in a diagram. The
sun was then 7 deg. or 8 deg. high, and there was a frost and a mist, which no
doubt acted as a darkening glass. Harriot does not apply the name of
spots to what he noticed in this observation, and he does not enumerate
it among the 199 observations above mentioned. Professor Rigaud[20]
considers it "a misapplication of terms to call such an observation a
discovery;" but, with all the respect which we feel for the candour of
this remark, we are disposed to confer on Harriot the merit of an
original discoverer of the spots on the sun.

[17] See page 40.

[18] These interesting MSS. I have had the good fortune of seeing
in the possession of my much valued friend, the late