An Admonitory Letter to the Calumniator.

Look here, Mersenne: see and behold Robert Fludd—whom you have so sharply provoked and challenged into the public arena of competition with slanders and insults—now coming forth. You deigned, first of all, to pore over his volumes strictly and by an analytical path, even with (as they say) the eyes of a Lynx original: "oculis... Lynceis." A classical reference to Lynceus the Argonaut, who was said to have sight so keen he could see through stone or into the earth.. By this diligence of yours, you have done him a very welcome service; for you have accurately inspected their method, and like an index, you have corrected and refuted errors: you have detected the marks of atheism, heresy, and magic within them with unheard-of caution. You have done well, if it was well enough, and as becomes a just and religious man—if it was done justly and religiously enough.

If, therefore, by returning like for like original: "par pari referendo." and compensating you with a similar measure of favor and diligence, Robert should lightly run through that volume of yours (all incivility set aside); if he should seek out certain errors in it and, with your leave, correct those he finds; if he should perhaps detect the stigmas of atheism, or at least of a true and not imaginary heresy; and if he should then afterwards revisit your observations on his own works—would anyone suppose that you, Marin, a man so Catholic and religious, indeed an imitator of Christ, and consequently by office humble, mild, and gentle, would rage beyond measure with unjust indignation? We call that man ungrateful who does not return a favor to one who deserves it; therefore, if it goes well enough, it will go well with you; but if ill, malice too will seek its own reward. Meanwhile, be wise and be well.

Rob. Fludd.