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XVI. On the Direction and Velocity of the Motion of the Sun, and 
Solar System . By William Herschel, LL. D . F. R. S. 
Read May ifi, 1805. 
Our attention has lately been directed again to the construc- 
tion of the heavens, on which I have already delivered several 
detached papers. The changes which have taken place in the 
relative position of double stars, have ascertained motions in 
many of them, which are probably of the same nature with 
those that have hitherto been called proper motions. It is well 
known that many of the principal stars have been found to 
have changed their situation, and we have lately had a most 
valuable acquisition in Dr. Maskelyne's Table of proper 
motions of six and thirty of them. If this Table affords us a 
proof of the motion of the stars of the first brightness, such as 
are probably in our immediate neighbourhood, the changes of 
the position of minute double stars that I have ascertained, many 
of which can only be seen by the best telescopes, likewise 
prove that motions are equally carried on in the remotest parts 
of space which hitherto we have been able to penetrate. 
The proper motions of the stars have long engaged the 
attention of astronomers, and in the year 1783, 1 deduced from 
them, with a high degree of probability, a motion of the sun 
and solar system towards A Herculis. The reasons which 
were then pointed out for introducing a solar motion, will now 
be much strengthened by additional considerations ; and the 
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