truth, and truth slowly but irrevocably prevails.[73] Theirs is the logic of discovery,[74] the demonstration of the advance of knowledge and the development of ideas, which as the earthly wants and passions of men remain almost unchanged, are the charter of progress, and the vital spark in history. And they often give us invaluable counsel when they attend to their own subjects and address their own people. Remember Darwin, taking note only of those passages that raised difficulties in his way; the French philosopher complaining that his work stood still, because he found no more contradicting facts; Baer, who thinks error treated thoroughly, nearly as remunerative as truth, by the discovery of new objections; for, as Sir Robert Ball warns us, it is by considering objections that we often learn.[75] Faraday declares that "in