VOL. XXXV.] PHILOSOPHICAL TRANSACTIONS. 237 



which he could do safely and readily. And even blindness he observed, 

 had this advantage, that he could go any where in the dark much better than 

 those who can see ; and after he had seen, he did not soon lose this quality, 

 nor desire a light to go about the house in the night. He said, every new ob- 

 ject was a new delight, and the pleasure was so great, that he wanted ways to 

 express it ; but his gratitude to his operator he could not conceal, never seeing 

 him for some time without tears of joy in his eyes, and other marks of affec- 

 tion : and if he did not happen to come at any time when he was expected, he 

 would be so grieved, that he could not forbear crying at his disappointment. A 

 year after first seeing, being carried upon Epsom Downs, and observing a large 

 prospect, he was exceedingly delighted with it, and called it a new kind of 

 seeing. And now being lately couched of his other eye, he says, that objects 

 at first appeared large to this eye, but not so large as they did at first to the 

 other ; and looking on the same object with both eyes, he thought it looked 

 about twice as large as with the first couched eye only, but not double, that 

 they could any ways discover. 



An Explanation of the Instruments used, in a neiv Operation on the Eyes. By 

 the same, N° 402, p. 45 1 , 



A, B, fig. 2, 3, pi. 5, represent two eyes, on which a new operation was per- 

 formed, by making an incision through the iris, which had contracted itself in 

 both cases so close, as to leave no pupil open for the admission of light. 



The perforation in the eye a was made a little above the pupil, the closing 

 of which ensued on the putting down a cataract, which not knowing how low 

 it might be lodged, Mr. C. made the incision a little higher than the middle, 

 lest any part of it should lie in the way. 



The eye b was one that was couched not long before, where the patient had 

 been blind but a few years. At first he thought every object further from him 

 than it was; but he soon learned to judge the true distance, the cause of which 

 Mr. C. explains by fig. 4, in which let the circle abc represent the eye, a the 

 place where an image through the natural pupil b was represented from the 

 place E. Now the artificial pupil being at the place c, the object at D is now 

 painted at the place a, where the object e was also to be perceived ; therefore it 

 was, he supposes, that the patient mistook the place d for the place e. 



Fig. 5 represents a kind of needle with an edge on one side, which being 

 passed through the tunica sclerotis, is then brought forwards through the iris a 

 a little farther than f. This done, he turns the edge of the needle, and cuts 

 through the iris as he draws it out. The handle of this needle is half black and 



