Source, in full
His well-known advice to the young William Crookes, who had asked him the secret of his success as a scientific investigator, as quoted in Michael Faraday (1874) by John Hall Gladstone, Section IV : His Method of Working, p. 123<!-- Full statement in that work
Notes from Wikiquote
It is on record that when a young aspirant asked Faraday the secret of his success as a scientific investigator, he replied, “The secret is comprised in three words — Work, Finish, Publish.”
Each of these words, we may be sure, is full of meaning, and will guide us in a useful inquiry. | also quoted with William Crookes specifically identified as the aspirant in other works, such as Michael Faraday : His Life and Work (1898) by Silvanus P. Thompson, p. 267 -->; this is also often rendered: "Work. Finish. Publish."