BLINDNESS. 



tions of the organs of sight, or from an 

 entire deprivation of them. 



This defect may arise from a variety of 

 causes, existing either in the organ of 

 sight, or in the circumstances necessary 

 to produce vision. Blindness will be 

 complete, when the light is wholly ex- 

 cluded ; or partial, when it is admitted 

 into the eye so imperfectly, as to convey 

 only a confused perception of visible ob- 

 jects. Blindness may again be distin- 

 guished into periodical or permanent, 

 transient or perpetual, natural or acci- 

 dental, &c. but these distinctions do not 

 serve to communicate any idea of the 

 causes of blindness. 



We find various recompenses for blind- 

 ness, or substitutes for the use of the eyes, 

 in the wonderful sagacity of many blind 

 persons, recited by Zahnius, in his " Ocu- 

 lus Artificialis," and others. In some, the 

 defect has been supplied by a most ex- 

 cellent gift of remembering what they 

 had seen ; in others by a delicate nose, 

 or the sense of smelling; in others, by 

 an exquisite touch or a sense of feeling, 

 which they have had in such perfection, 

 that, as it has been said of some, they 

 learned to hear with their eyes ; as it may 

 be said of these, that they taught them 

 selves to see with their hands. Some 

 have been enabled to perform all sorts of 

 curious and subtle works in the nicest and 

 most dexterous manner. 



Aldrovandus speaks of a sculptor who 

 became blind at twenty years of age, 

 and yet, ten years after, made a perfect 

 marble statue of Cosmo IT. de Medicis ; 

 and another of clay like Urban VIII. 



Burtholin tells us of a blind sculptor in 

 Denmark, who distinguished perfectly 

 well, by mere touch, not only all kinds of 

 wood, but all the colours ; and F. Gri- 

 maldi gives an instance of the like kind ; 

 besides the blind organist, living in Pa- 

 ris, who is said to have done the same. 

 The most extraordinary of all is a blind 

 guide, who, according to the report of 

 good writers, used to conduct the mer- 

 chants through the sands and deserts of 

 Arabia. 



James Bernouilli contrived a method of 

 teaching blind persons to write. 



An instance, no less extraordinary, is 

 mentioned by Dr. IJew, in the " Transac- 

 tions of the Manchester Society." It is 

 that of a person, whose name is John 

 Melcalf, a native of the neighbourhood of 

 Manchester, who became blind at so ear- 

 ly an age as to be altogether unconscious 

 of light and its various effects. His em- 

 ployment in the younger period of his 



life was that of a wagoner, and occasion- 

 ally as a guide in intricate roads during 

 the night, or when the common tracks 

 were covered with snow. Afterwards 

 he became a projector and surveyor of 

 highways in difficult and mountainous 

 parts ; and in this capacity, with the as- 

 sistance merely of a long staff, he tra- 

 verses the roads, ascends precipices, ex- 

 plores vallies, and investigates their seve- 

 ral extents, forms, and situations, so as to 

 answer his purpose in the best manner. 

 His plans are designed, and his estimates 

 formed, with such ability and accuracy, 

 that he has been employed in altering 

 most of the roads over the peak in Der- 

 byshire, particularly those in the vicinity 

 of Buxton, and in constructing a new one 

 between Wilmslow and Congleton, so as 

 to form a communication between ihe 

 great London road, without being obliged 

 to pass over the mountain. 



Although blind persons have occasion, 

 in a variety of respects, to deplore their 

 infelicity, their misery is in a consider- 

 able degree alleviated by advantages pe- 

 culiar to themselves. They are capable 

 of a more fixed and steady attennon to 

 the objects of their mental contempla- 

 tion, than those who are distracted by 

 the view of a variety of external scenes. 

 Their want of sight naturally 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 disre- 

 gard. 



Many contrivances have also been de- 

 vised by the ingenious for supplying the 

 want of sight, and for facilitating those 

 analytical 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 with- 

 out mechanical helps, the blind have not 

 distinguished themselves. 



The case of Professor Saunderson at 

 Cambridge is well known. His attainments 

 and performances in the languages, and 

 also as a learner and teacher in the ab- 

 stract mathematics, 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 



