6 ' 
Mr. Home's Lecture 
although inconvenient to himself, till they were Completed ; 
the greater part of them were instituted by Mr. Ramsden, and 
ail of them carried through under his direction. 
The experiments were begun on the 22d of December, 1 793, 
at which time the following observations were made upon the 
imperfect eye. The eye bore the light of the day very well ; 
but was fatigued by strong sunshine, or the glare of candle- 
light. In weak lights objects were not seen at all by the im- 
perfect eye, but in strong lights they presented a faint image, 
which appeared at the same distance with that seen by the 
perfect eye, and close to it, or nearly so, but always to the 
left. 
The imperfect eye, unassisted by glasses, could see objects, 
but it was with a degree of indistinctness ; and this indistinct 
vision only took place at a distance between six and nine 
inches. With a double convex glass, the radius of one sur- 
face an inch and an half, of the other six inches, the flat side 
towards the eye, having’ a focus of 2^ inches, objects ap- 
peared most distinct at 4^ inches, and the extremes were 2^ 
inches, and inches. The different distances were ascertained 
by placing one end of a foot rule against the man's fore- 
head, and giving him the book in his own hand, desiring 
him to carry it to the distance at which he saw best, and 
afterwards to the two extremes of distinct vision, the upper 
end of the book being always in contact with the rule; so 
that the moment he adjusted the book, the distance was read 
off from the scale. The accuracy with which he brought it 
to the same point in repeating the experiments, proved his eye 
to be uncommonly correct ; for as he did not himself see the 
scale, there could be no source of fallacy. 
