Inventor and astronomer. Born in Garvald (East Lothian). Blair became the first Professor of Astronomy at the University of Edinburgh. He was the inventor of the aplanatic telescope, which does not suffer from spherical aberration. He investigated substitutes for flint glass and methods of removing secondary spectra. He used hollow lenses, filled with a solution of hydrochloric acid and salt. Sir David Brewster (1781 - 1868) was a contemporary, and praised Blair's work.
Blair also helped banish scurvy in the Royal Navy.