"That vibrations [in the air above London] which are nearly isochronous affect and modify one another, so as to become perfectly so, sufficiently corresponds to the phænomena of ideas, and therefore makes no objection to this doctrine."
— Priestley, Joseph (1733-1804)
See Hartley’s Theory of the Human Mind, on the Principle of the Association of Ideas; With Essays Relating to the Subject of It. By Joseph Priestley, LL. D. F. R. S. (London: Printed for J. Johnson, No. 72, St. Paul’s Church-Yard, 1775). <Link to ESTC>