In response to the question, "What is the use of having two eyes?" the answer has been given, "To have one left if the other is hurt." Much as we may admire the sagacious foresight of this youthful physiologist, it will not be found sufficient to rest contented with his ultimatum. He had evidently not tried his skill to flnd how unexpectedly he would miss the inkstand while endeavoring to dip his pen into it at arm's length, with one eye closed. He had not thought of holding his finger a few inches in front of his face to flnd what part of the wall it would hide from each eye in succession, or how differently it would look when regarded from those two pointe of view separately, how much thi kei it would appeai1 when both eyea were open, how readily he could examine three sides of it at once, how much more deünitely he could judge lts distance, in a word how much more comprehensivo was the information given by two eyes if used at the same moment. Assuming1 that he knows exaotly how to account for the inversión of the retinal image and the erect appearance of theobjeotthere pictured, how our visïial perceptions are only signs of what we momentarily feel on the retina, signs that generally represent the realities with a fair degree of accuracy, but may sometimes represent almost anything else on demand. how, if the eves be healthy, we have no consciousness of possessing any retina at all, but instantly and unconsciously refer every retinal sensation to some external body whose exiatence we are obliged to assume, unless there be special arguments to convince us to the contrary - granting all this, our young physiologist has not thought oí inquiriug how it is that, although two retinal images are produced, we see but a single object, and this despite the fact that, like photographsol' the same body simultaneously taken from different stand-points, these two images are necessarily dissimilar. - Popular 8aien.ce Monthly. Geo. Otto Trevelyan, the new Chief Seoretary for Ireland, is a nephew of the late Lord Macaulay, and 'm best known in this country as the editor of Macaulay's Life and Letter.-. For the last iew years )ip bas beeu Secretary of the Admiralty, the office filled by Samuel Pepys in the time of CharleB il and hia brother James. He represent the district of Har wiek, Scotland, and ranks as Liberal in Parliament.