To [John Canton7]
ALS: The Royal Society
March 9. 68
Dr. Priestly left these Specimens of the Circles with me to be produc’d to the Society. As I cannot be there this Evening, when I understand the Paper is to be read, 8 I inclose them to you. Those that look at them should be caution’d not to rub them, lest they should be defac’d before the Company have all had a Sight of them. I am, Yours &c.
7. The letter is among the Canton Papers (III, fol. 1) in the Royal Society, a fact that establishes the identity of the addressee. For John Canton, electrical experimenter, F.R.S., and twice winner of the Copley medal, see above, IV, 390 n.
8. Priestley’s paper was actually read on March 10: “an Account of Rings Consisting of All the Prismatic Colours, Made by Electrical Explosions on the Surfaces of Pieces of Metal,” Phil. Trans., LVIII (1768), 68–74. For Priestley see above, XIII, 185 n.