2 
Mr. Home's Lecture on the Power of the Eye, 
without availing myself of this opportunity of paying that tribute 
of gratitude to his memory, which feelings of delicacy prevented 
me from offering to him while alive. It is unnecessary here to 
mention his genius, his merits, or his exertions for the promo- 
tion of science; these are equally well known to every member 
present, as to myself. It is only my individual obligations, in 
the prosecution of inquiries connected with the objects of this 
learned Society, that are meant to be taken notice of. 
To his friendly and zealous assistance I am indebted for the 
information which was necessary to enable me to prosecute 
investigations upon the subject of vision ; and, without such 
assistance, I should have shrunk from the inquiry. It is also 
to his early friendship, and his readiness to communicate to me 
his knowledge, that I look back, as among the sources of my 
early exertions, and love of philosophical pursuits. 
In the year 1794, I laid before this learned Society some 
experiments, suggested and made by Mr. Ramsden, upon the 
comparative powers of adjustment of the eye, when in a perfect 
state, and when deprived of the crystalline lens. From the 
result of these experiments it appeared, that the removal of the 
lens did not deprive the eye of the power of seeing distinctly at 
different distances. As the person upon whom the experiments 
were tried did not see very distinctly, without a substitute for 
the lens, in making them, a double convex glass, of sf inches 
focus, was placed before his eye ; and, to render the image dis- 
tinct, by correcting the spherical aberrations, the aperture was 
diminished to - 3 -ths of an inch ; a less degree of diminution 
not answering that purpose. 
The subject of these experiments was Benjamin Clerk, 
twenty-one years of age; one of his eyes was in a very perfect 
