16 Biographical Account of Dr Wilson. 



manner by which the motion of light would be affected by re- 

 flecting and refracting media, themselves moving with great ve- 

 locity, (a most interesting field in optics then wholly unculti- 

 vated,) that two principles came into view, either of which may 

 possibly serve us in detecting a general motion belonging to the 

 solar system, relatively to the surrounding fixed stars, or in 

 proving a negative with regard to it. Of these, a very sum- 

 mary account has been given in the historical part of the Edin- 

 burgh Philosophical Tra7isactions, vol. i. But, should they be 

 successful in discovering such a concealed motion, the same 

 pnnciples cannot fail of determining the velocity and direction 

 of it ; and in process of time, whether such a translation of the 

 whole system be in a straight line or a curve, and if in a curve, 

 whether it be of a such a kind as may indicate a periodical re- 

 volution. And it needs scarce be mentioned, that if such a 

 thing should actually be made out, besides enriching astronomy 

 with that knowledge which depends upon measureable paral- 

 laxes in the sphere of the starry firmament ; it would also be- 

 stow a very high authority upon Dr Wilson's suggestions, of 

 what possibly may be the plan of nature in upholding the 

 universe. 



At the time of the last-mentioned publication, he was sixty- 

 three years old, but still continued to enjoy the blessings of an 

 uninterrupted state of good health. In the year 1784, at the 

 recommendation of the university, his Majesty was graciously 

 pleased to nominate and appoint Patrick Wilson, A. M. Dr 

 Wilson's second son, to be assistant and successor to his father 

 as professor of practical astronomy and observer; a circum- 

 stance which heightened the consolations he enjoyed during 

 the evening of life. 



In March and April 1786, when he had nearly completed 

 his seventy-second year, it became apparent to his family and 

 friends, that his constitution and strength were fast declining. 

 After a gradual and easy decay, which lasted throughout the 

 whole of that summer and autumn, and which he bore with 

 the utmost composure and resignation, amidst the tender soli- 

 citudes of his surrounding family, he at last expired in their 

 arms, on the 16th day of October. 



The private character of Dr Wilson was amiable to an un- 



