of Mr Charles Bell 265 



as no objection was stated to his views, he had reason to believe 

 from this, as well as from other causes, that there was not one 

 of the numerous members then present, who did not concur in 

 the refutation which he had given of Mr Bell's paper. 



As Mr Bell had now embalmed his erroneous views in the 

 Transactions of the Royal Society of London, and in the Me- 

 mory of the Royal Society of Edinburgh, the two great sci- 

 entific bodies of the kingdom, and by publishing a defence 

 of his doctrines, had evinced a resolution to maintain them at 

 all hazards, it might have been thought advisable to put 

 down, with a strong hand, a philosophical heresy, which had 

 assumed such an obtrusive character, and which had come be- 

 fore the world apparently under such imposing patronage. 

 We, however, had resolved not to disturb its repose. Scienti- 

 fic truth, when once clearly expressed, forces its way in silence 

 to the judgment-seat of time ; and her march is rendered only 

 more quick, and more steady, by the clamours and the imperti- 

 nences with which she may be assailed. 



Under such feelings we had determined to be silent. But, 

 while perusing Dr Wells's Essay upon Single Vision with Two 

 Eyes, published at London in 1792, we were surprised to 

 find that the experiments and conclusions, brought forward 

 by Mr Bell as his own, were given in the most minute man- 

 ner by Dr Wells. We felt ourselves, therefore, called upon 

 to resume the subject, and to point out the fallacies by which 

 this distinguished writer was led to maintain, and to apply to 

 the explanation of the phenomena of vision, opinions so con- 

 trary to reason and experiment. 



The following are the passages in which Dr Wells has record- 

 ed his opinions : 



" When we have looked steadily for some time at the flame of a candle, 

 or any otber luminous body, a coloured spot will appear upon every object 

 to which we shortly after direct our eyes, accompanying them in all their 

 motions, and exactly covering the point which we desire to see the most 

 accurately. Whatever can, therefore, be proved concerning the apparent 

 direction of such a spot, in any given position of the eyes, must likewise be 

 true in the same position of the eyes, with regard to the apparent direction 

 of an object situated at the concurrence of the optic axes, as its pictures 

 must occupy, in this case, the very parts of the retinas, upon the affections 

 of which the illusion of the spot depends. This being premised, I shall 

 now relate one or two observations respecting the apparent directions of the 



