150 
EASTMAN. 
eral way estimate, that the solar motion can certainly not 
he less than that which the earth has in her annual orbit.” 
In this paper we have the first attempt to determine the 
direction and amount of Solar motion; and, though the 
problem was not subjected to any real mathematical analysis, 
it is remarkable thalt the concluded direction of motion com¬ 
pares favorably with the later determinations from a rigid 
mathematical treatment of a far greater amount of data. 
During the remainder of the eighteenth century nothing of 
importance was added to the subject. 
In 1805, Herschel 8 resumed the study of the problem, and 
with wider experience, and more and better data, he was 
led to believe that he had determined with greater accuracy 
the position of the solar apex, and gave its right ascension 
as 245° 52' 30" and its north polar distance 40° 22'. 
In the following year Herschel 9 presented to the Royal 
Society the results of an extensive investigation of the 
“Quantity and Velocity of the Solar Motion,” in the follow¬ 
ing terms:— 
“ It appears, therefore, that in the present state of our 
knowledge of the observed proper motions of the stars, we 
have sufficient reason to fix upon the quantity of the solar 
motion to be such as by an eye placed at right angles to its 
direction and at the distance of Sirius from us, would be seen 
to describe annually an arc of 1".116992 of a degree; and 
its velocity, till we are acquainted with the real distance of 
this star, can therefore only be expressed by the proportional 
number of 1116992.” 
About the beginning of the nineteenth century astrono¬ 
mers began to consider analytical methods of discussing the 
data at hand, and a new epoch was reached in the progress 
of the investigation. Kliigel 10 had already developed special 
Trigonometrical formulae but had not employed them in any 
computation. In 1809, Burckhardt * 11 presented an ingenious 
8 Herschel, William. Philosophical Transactions, 1805; 233. 
9 Herschel, William. Philosophical Transactions, 1806 ; 205. 
10 Kliigel, Gr. S. Astronomisches Jahrbueh, 1789 ; 214. 
11 Burckhardt, J. C. Connoissance des Temps, 1809 ; 377. 
