the near and distant Sight of different Persons. 331 
tisfactory information, by making inquiry in those places 
where a large number in these several classes are associated 
together. I have inquired, for instance, of the surgeons of 
the three regiments of foot guards, which consist of nearly 
ten thousand men; and the result has been, that near- 
sightedness, among ‘the privates, is almost utterly unknown. 
Not half a dozen men have been discharged, nor half a 
dozen recruits rejected, on account of this imperfection, in 
the space of nearly twenty years: and yet many parts of 
a soldier’s duty require him to have a tolerably correct 
view of distant objects; as of the movements of the fugle- 
man in exercise, and of the bull’s eye when shooting at 
the target; the want of which might furnish a_ plausible 
apology for a skulker to skreen himself from duty, or to 
get his discharge from the service. I pursued my inquiries 
at the military schoo] at Chelsea, where there are thirteen 
hundred children, and I found that the complaint of near- 
sightedness had never been made among them until I men- 
tioned it; and there were then only three who experienced 
the least inconvenience from it. After this, | inquired at 
several of the colleges in Oxford and Cambridge; and, 
though there is a great diversity in the number of students 
who make use of glasses in the various colleges, they are 
used by a considerable proportion of the whole number in 
both universities; and, in one college in Oxford, I bave 
a list of the names of not Jess than thirty-two out of one 
hundred and twenty-seven, who wore either a hand glass 
or spectacles, between the years 1803 and 1807. It is not 
‘improbable, that some of these were induced to do it solely 
because the practice was fashionable; but, I believe, the 
number of such is inconsiderable, when "compared with 
that of those whose sight received some small assistance 
from them, though this assistance could have been dis= 
pensed with, without inconvenience, if the practice had 
not been introduced. The misfortune resulting from the use 
of concave glasses is this, that the near- sightedness is not 
only fixed by it, but a habit of inquiry is induced with re- 
gard to the extreme perfection of vision; and, in conse- 
quence of this, frequent changes are made for glasses that 
are more and more concave, until at length the near- 
sightedness becomes so considerable, as to be rendered se- 
riously inconvenient and afflicting. It should be remem- 
bered, that, for common purposes; every near-sighted eye 
gan see with nearly equal accuracy through two glasses, 
one of which is one number deeper than the other; and 
though the sight be ina slight degree more assisted by the 
deepest 
