BLINDNESS. 
'cd, with such ability and accuracy, that he 
has been employed in altering most of the 
roads over the Peak in Derbyshire, particu- 
larly those in the vicinity of Buxton, and 
in constructing a new one between Wilm- 
slow and fiongleton, so as to form a com- 
munication between the great London road, 
without being obliged to pass over the 
.mountain. 
Although blind persons have occasion, in 
a variety of respects, to deplore their in- 
felicity, their misery is in a considerable 
degree alleviated by advantages peculiar to 
themselves. They are capable ot a more 
fixed and steady attention to the objects of 
their mental contemplation, than those who 
are distracted by the view of a variety of 
external scenes. Their want of sight natu- 
rally leads them to avail themselves of their 
other organs of corporeal sensation, and 
with this view to cultivate and improve 
them as much as possible. Accordingly 
they derive relief and assistance from the 
quickness of their hearing, the acuteness of 
their smell, and the sensibility of their 
touch, which persons who see are apt to dis- 
regard. 
Many contrivances have also been de- 
vised by the ingenious for supplying the 
want of sight, and for facilitating those ana- 
lytical or mechanical operations, which 
would otherwise perplex the most vigorous 
mind and the most retentive memory. By 
means of these they have become eminent 
proficients in various departments of science. 
Indeed there are few sciences in which, 
with or without mechanicai helps, tire blind 
have not distinguished themselves. 
The case of Professor Saunderson at Cam- 
bridge is well known. His attainments and 
performances in the languages, and also as 
a learner and teacher in the abstract ma- 
thematics, in philosophy, and in music, have 
been truly astonishing ; and the account of 
them appears to be almost incredible, if it 
were not amply attested and confirmed by 
many other instances of d similar kind, both 
in ancient and modern times. 
Cicero mentions it as a fact scarcely cre- 
dible, with respect to his master in philoso- 
phy, Diodotus, that “he exercised him- 
self in it with greater assiduity after he be- 
came blind ; and which he thought next to 
impossible to be performed without sight; 
that he professed geometry, and described 
his diagrams so accurately to his scholars, as 
to enable them to draw every line in its 
proper direction.” 
Jerom relates a more remarkable instance 
of Didymus in Alexandria, who, “ though 
blind from his infancy, and therefore igno- 
rant of the letters, appeared so great a mi- 
racle to the world, as not only to learn lo- 
gic, but geometry also to perfection, which 
seems (he adds) the most of any thing to 
require the help of sight ” 
Professor Saunderson, who was deprived 
of his sight by the small pox, when he was 
only twelve months old, seems to have ac- 
quired most of his ideas by the sense of 
feeling; and though he could not distin- 
guish colours by that sense, which, after re- 
peated trials, he said was pretending to 
impossibilities, yet he was able, with the 
greatest exactness, to discriminate the mi- 
nutest difference of rough and smooth in a 
surface, or the least defect of polish. In a 
set of Roman medals, he could distinguish 
the genuine from the false, though they had 
been counterfeited in such, a manner, as to 
deceive a connoisseur, w'lio judged of them 
by tire eye. His sense of feeling was so 
acute, that he cotdd perceive the least va- 
riation in the state of the air ; and, it is 
said, that in a garden where observations 
were made on the sun, he took notice of 
every cloud that interrupted the observa- 
tion, almost as justly as those who could see 
it. He could tell when any thing was held 
near his face, or when he passed by a tree 
at no great distance, provided the air was 
calm, and there was little or no wind : this 
he did by the different pulse of air upon his 
face. He possessed a sensibility of hearing 
to such a degree, that he could distinguish 
even the fifth part of a note ; and, by the 
quickness of this sense, he not only discri- 
minated persons with whom he had once 
conversed so long as to fix in his memory 
the sound of their voice, but he could judge 
of the size of a room into which he was in- 
troduced, and of his distance from the wall ; 
and if he had ever walked over a pavement 
in courts, piazzas, &c. which reflected a 
sound, and was afterwards conducted thi- 
ther again, he could exactly tell in what part 
of the walk he was placed, merely by the 
note which it sounded. 
Sculpture and painting are arts which, 
one would imagine, are of very difficult and 
almost impracticable attainment to blind 
persons; and yet instances occur, which 
shew that they are not excluded from the 
pleasing, creative, and extensive regions of 
fancy. 
De Piles mentions a blind sculptor, who 
thus took the likeness of the Duke de Brac- 
ciano iu a dark cellar, and made a marble 
