15 OCTOBER 1831, Page 20

Mr. FE ARN, the metaphysician, whose labours have been but

very scantily appreciated, because, though he had consented to give all his life to metaphysical investigations, he has utterly neglected to provide a popular medium of conveying them to the world—viz. that arrangement of words which is called style—has just published a pamphlet, entitled Colour Images in the .Brain. It is a sequel of a pamphlet on the same subject which appeared in the course of the year. The experiments which were then detailed, are perhaps the most important that have ever been made in optics; and it is certainly the duty of every man who pretends to optical knowledge, instantly to proceed to the repetition and confirmation of them; they are of the very simplest kind in themselves, but in their results perhaps none can be more important. The simple experiment may be thus explained : if two objects (for instance, a sovereign and a shilling) be placed in a case or spectrum, the one before one eye and the other before the other eye, in such a manner that the nose intervenes and prevents the right eye from perceiving the left object, and vice versa,—then will the left object be seen in the right eye, and the right object in theleft eye,—showing, as plainly as experiment can show, that the sight of the right eye catches the left object through the left eye, or in other words, that sight is in the brain. These experiments nave been presented to the Royal Society, and a report has been made upon them, which has drawn forth this pamphlet. Judging from Mr. FEARN'S quotation from the production under the sanc- tion of the Royal Society, it does appear plain that the reporter either would not or could not understand the nature of the ex- periment or the object of his reasoning. These experiments only require to be known, at least to meet with attention.