"Although there may be some few exceptions, yet in general it holds, that when the bent of the mind is wholly directed towards some one object, exclusive, in a manner, of others, there is the fairest prospect of eminence in that, whatever it be. The rays must converge to a point, in order to glow intensely."
— Blair, Hugh (1718-1800)
(Vol. I, Lecture III, pp. 49-50; pp. 23-4 in SIUP ed.)
See Lectures on Rhetoric and Belles Lettres. By Hugh Blair (London: Printed for W. Strahan; T. Cadell; and W. Creech, in Edinburgh, 1783): <Link to ESTC>. See also Dublin edition of same year in ECCO-TCP: <Link to Vol. I><Vol. II><Vol. III>. Revised and corrected for second edition of 1785.
Reading Lectures on Rhetoric and Belles Lettres, eds. Linda Ferreira-Buckley and S. Michael Halloran (Carbondale: Southern Illinois UP, 2005). Text based on second edition of 1785.