whereupon he said that immediately on opening his eye he had discovered a difference in the two objects, the cube and the sphere, placed before him, and perceived that they were not drawings; but that he had not been able to form from them the idea of a square and a disk, _until he perceived a sensation of what he saw in the points of his fingers_, as if he really touched the objects. When I gave the three bodies, the sphere, cube, and pyramid, into his hand, he was much surprised that he had not recognized them as such by sight, as he was well acquainted with them by touch. These experiments prove the correctness of the hypothesis I have advanced elsewhere on the well-known question put by Mr. Molyneux to Locke, which was answered by both these gentlemen in the negative. "_Fourth Experiment._--In a vessel containing water to about the depth of one foot was placed a musket-ball, and on the surface of the water a piece of pasteboard of the same form, size, and color as the ball. The patient could perceive no difference in the position of these bodies; he believed both to be upon the surface of the water. Pointing to the ball, I desired him to take up this object. He made an attempt to take it from the plane of the water; but, when he found he could not grasp it there, he said he had deceived himself, the objects were lying in the water, upon which I informed him of their real position. I now desired him to touch the ball which lay in the water with a small rod. He attempted this several times, but always missed his aim. He could never touch the object at the first movement of his hand toward it, but only by feeling about with the rod. On being questioned with respect to reflected light, he said that he was always obliged to bear in mind that the looking-glass was fastened to the wall in order to correct his idea of the apparent situation of objects behind the glass.