In fact, a man born blind was found in 1729, by whom this question was indubitably decided. The famous Cheselden, one of those celebrated surgeons who join manual skill to the most enlightened minds, imagined that he could give sight to this blind man by couching, and proposed the operation. The patient was with great difficulty brought to consent to it. He did not conceive that the sense of sight could much augment his pleasures, except that he desired to be able to read and to write, he cared indeed little about seeing. He proved by this indifference that it is impossible to be rendered unhappy by the privation of pleasures of which we have never formed an idea--a very important truth. However this may be, the operation was performed, and succeeded. This young man at fourteen years of age saw the light for the first time, and his experience confirmed all that Locke and Berkeley had so ably foreseen. For a long time he distinguished neither dimensions, distance, nor form. An object about the size of an inch, which was placed before his eyes, and which concealed a house from him, appeared as large as the house itself. All that he saw seemed to touch his eyes, and to touch them as objects of feeling touch the skin. He could not at first distinguish that which, by the aid of his hands, he had thought round from that which he had supposed square, nor could he discern with his eyes if that which his hands had felt to be tall and short were so in reality. He was so far from knowing anything about magnitude that after having at last conceived by his sight that his house was larger than his chamber, he could not conceive how sight could give him this idea. It was not until after two months' experience he could discover that pictures represented existing bodies, and when, after this long development of his new sense in him, he perceived that bodies, and not surfaces only, were painted in the pictures, he took them in his hands and was astonished at not finding those solid bodies of which he had begun to perceive the representation, and demanded which was the deceived, the sense of feeling or that of sight. Thus was it irrevocably decided that the manner in which we see things follows not immediately from the angles formed in the eye. These mathematical angles were in the eyes of this man the same as in our own and were of no use to him without the help of experience and of his other senses. The adventure of the man born blind was known in France towards the year 1735. The author of the "Elements of Newton," who had seen a great deal of Cheselden, made mention of this important discovery, but did not take much notice of it. And even when the same operation of the cataract was performed at Paris on a young man who was said to have been deprived of sight from his cradle, the operators neglected to attend to the daily development of the sense of sight in him and to the progress of nature. The fruit of this operation was therefore lost to philosophy.