WS Epa be oP 
given, to thofe who are in want of 
afliftance from glaffes, in order fo 
to choofe their {pectacles, that they 
may fuit the itate of their eyes, is 
to prefer thofe which thew objects 
neareft their natural flate, neither 
enlarged nor diminifhed, the glaffes 
being near the eye, and that give a 
blacknefs and diftin€inefs to the let- 
ters of a book, neither ftraining the 
eye, vor caufing any unnatural ex- 
ertion of the pupil. 
_ For no fpeftacles can be faid to 
tbe properly accommodated to the 
‘eyes, which do not procure them 
gale and reft; if they fatigue the 
eyes, we may fefely conclude, either 
that we have no occafion for them, 
or that they are ill made, or not 
proportioned to our fight 
Though, in the choice of fpec- 
tacles, every one mult finally deter- 
mine for hbimfelf, which are thea 
oe through which he obtains 
e mot diftinct vifion; yet fome 
confidence fhould be placed in the 
judgment of the artift, of whom 
‘they are purchafed, and fome atten- 
tion paid to his direétions. By try- 
“ing many {fpedtacles the eye is fa- 
tigued, as the pupil varies in fize 
with every different glafs, and the 
eye endeavoprs to accommodate it- 
felf to every change that is pro- 
daced. Hence, the purchafer often 
fixes upon a pair of {pectacles, not 
the beit adapted to his fight, but 
thofe which feem to relieve him 
mott, while his eyes are in a forced 
and unnatural ftate; and confe- 
quently, when he gets home, and 
Bey are returned to their natural 
fare, he finds what he has chofen 
fatiguing and injurious to his 
fight. 
ROPHETS. 93 
Of Prefervers, and Rules for the 
Prefervation of the Sight. 
Though it may be impoffible to 
prevent the abfolute decay of fight, 
whether arifing from age, partial 
difeafe, or illnefs, yet by prudence 
and good management, its natural 
failure may certainly be retarded, 
and the general habit of the eyes 
ftrengthened, which good purpofes 
will be promoted by a proper atten- 
tion to the following maxims, 
1. Never to fit for any length of- 
time'in abfolute gloom, or expofed 
toa blaze of light. ‘The reafons 
on which this rule is founded, prove 
the impropriety of yoing haftily 
from one extreme to the other, 
whether of darknefs or of light, and 
fhew us, that a fouthern afpect is 
improper for thofe whofe fight is 
weak and tender. 
z. To avoid reading a {mall 
print. 
3. Not to read in the dufk; nor, 
if the eyes be difordered, by candle- 
light. Happy thofe who learn this 
leffon betimes, and begin to pre- 
ferve their fight, before they are 
reminded by pain, of the neceflity 
of {paring them; the frivolous az. 
tention to a quarter of an hour of 
the evening, has coft numbers the 
perfect and comfortable ufe of their 
eyes for many years: the mifchief 
is effected imperceptibly, the con- 
{equences are inevitable. 
4. The eye fhould not be per- 
mitted to dwell on glaring obje&s, 
more particularly on firft waking in 
a morning; the fun fhould not of 
courfe be fuffered to fhine in the 
room at that time, and a moderate 
quantity of light only be admitted, 
Jt is eafy to fee, that for the fame 
reafons, the furniture of a bed 
should be neither altogether of a 
white 
