Internal and external sensation, "These alone, as far as I can discover, are the windows by which light is let into this dark room: For methinks the understanding is not much unlike a closet wholly shut from light, with only some little openings left, to let in external visible resemblances, or ideas of things without"
— Locke, John (1632-1704)
I find over 25 entries in the ESTC (1690, 1694, 1695, 1700, 1706, 1710, 1715, 1721, 1726, 1731, 1735, 1741, 1748, 1753, 1759, 1760, 1765, 1768, 1775, 1777, 1786, 1788, 1793, 1795, 1796, 1798). See also the many abridgements issued in the period.
First published as An Essay Concerning Humane Understanding. In Four Books. (London: Printed by Eliz. Holt, for Thomas Basset, at the George in Fleetstreet, near St. Dunstan's Church, 1690). <Link to EEBO><EEBO-TCP>
Searching first in a Past Masters edition based on the 12th Edition of Locke's Works and proofread against the 1959 Fraser edition. More recent searches in EEBO-TCP.
Reading John Locke's An Essay Concerning Human Understanding, ed. Peter Nidditch (Oxford, Oxford UP, 1975)--against which I have checked the text searched in Past Masters. Note, Nidditch's text is based on 4th ed. of 1700.