Page:Ferrier's Works Volume 3 "Philosophical Remains" (1883 ed.).djvu/357

we cannot agree with them; we think that it is a fact as recondite and as worthy of being stated as many others that are emphatically insisted on in the science. Or else, though neither notorious nor familiar, it may have been stated by some one or by some few optical writers. If so, we should thank any one who would be kind enough to refer us to the works in which it is to be found. Or else, fourthly, it is a false fact, and admits of being demonstrably disproved. If so, we should like to see it done. Or else, lastly, it is true, and a new, and a demonstrable fact; and if so, we now call upon all optical writers, from this time henceforward, to adopt it. We do not pretend to decide which of these views is the true one. We look to Dr Brewster for a reply; for neither his, nor any other man's rationale of the inverted images, appears to us to be at all complete or satisfactorily made out without its admission.