4 ACCOUNT OF A BOY 



point of accuracy, very nearly to those which we are ac- 

 customed to form by means of the eye. I had once occasion 

 to witness the precision with which Mr Gough of Ken- 

 dal (by far the most intelligent and ingenious person, born 

 blind, whom I have happened to meet with) guessed at the di- 

 mensions of a large room, a few minutes after he entered it. 

 The error he committed was a mere trifle ; not exceeding what 



might 



push his argument against Cheselden so far as has been apprehended by some 

 later writers. In the following passages, he not only seems to admit the truth 

 of that optical principle whicli he has been generally understood to contro- 

 vert, but even points at tlie same explanation which I have already suggested, 

 of the apparent inconsistency between his own experience and that of his prede- 

 cessor. 



" I beg leave (says he) to add further, that on making inquiries of two chil- 

 dren, between seven and eight years of age, now under my care, both of 

 whom have been blind from birth, and on whom no operation has yet been per- 

 formed, I find that the knowledge they have of colours, limited as it is, is suf- 

 ficient to enable them to tell whether coloured objects be brought nearer to, 

 or carried farther from them ; for instance, whether they are at the distance 

 of two inches or four inches from their eyes. 



" I am aware, that these observations not only differ from those that are re- 

 lated of Mr Cheselden's patient, but appear, on the first statement, to oppose 

 a principle in optics, which I believe is commonlj/ and justly admitted, that the 

 senses of sight and feeling have no other connection but that which is formed 

 by experience ; and therefore, that the ideas derived from feeling, can have no 

 power to direct the judgment, with respect either to the distance or form of 

 visible objects. It should be recollected, however, that persons who have ca- 

 taracts in their eyes, are not, in strictness of speech, blind, though they are 

 deprived of all useful sight. The instances I have adduced prove, tliat the 

 knowledge they have of colours is sufficient to give them some idea of dis- 

 tance, even in their darkest state. When, therefore, their sight is cleared by 

 the removal of the opaque crystalline which intercepted the light, and the co- 

 lour of objects is thereby made to appear stronger, will it be difficult or un- 

 philosophical to conceive, that their ideas of distance will be strengthened, 

 and so far extended, as to give them a knowledge even of the outline and 

 figure of those objects with the colour of which they were previously ac- 

 <]uainted ?" 



