Dr. Wells's Observations 
S 8S 
of distances, as those who enjoy the most perfect vision. At 
the age of fifty, however, he began to observe, that distant 
objects, though viewed through his glasses, appeared indis- 
tinct, and he was hence led to fear, that his eyes were affected 
with some disease. But happening one day to take up, in an 
optician’s shop, a single concave glass, and to hold it before 
one of his eyes, while his spectacles were on, he found to his 
great joy, that he had regained distinct vision of distant objects. 
With regard to such objects, therefore, he had lately become 
shorter-sighted than he had formerly been. But along with 
this change, another occurred of a directly opposite kind. For 
when he wished to examine a minute object attentively, such 
as he used to see accurately by means of his spectacles, he 
now found it necessary to lay them aside, and to employ his 
naked eye. He had become, therefore, in respect to near 
objects longer-sighted. The power, consequently, in this 
gentleman, to adapt the eye to different distances, is either 
totally lost or much diminished ; but the point, or small space 
to which his perfect vision is now confined, instead of being 
the most remote to which he could formerly accommodate 
his eyes, as is commonly the case with the ordinarily sighted 
when they are becoming old, is now placed between the two 
extremes of his former range of accurate vision. The eyes 
of the other short-sighted person, a physician of considerable 
learning, whose vision has been altered by age, have been 
affected in a similar manner, but not in so great a degree. 
As the only change, which had occurred from age in the 
sight of such of my acquaintance as were considerably myopic 
was a lessening, on both sides, of their range of perfect vision, 
I conceived that this might be the ordinary procedure of 
