mind and the acquisition of knowledge. He was sent when very young to the free school at Penistone, in the neighbourhood of his native place; and here, notwithstanding the mighty disadvantage under which it would seem that he must have contested with his school-fellows, he soon distinguished himself by his proficiency in Greek and Latin. It is to be regretted that we have no account of the mode of teaching that was adopted by his master in so singular a case, or the manner in which the poor boy contrived to pursue his studies in the absence of that sovereign organ to which the mind is wont to be chiefly indebted for knowledge. Some one must have read the lesson to him, till his memory, strengthened by the habit and the necessity of exertion, had obtained complete possession of it, and the mind, as it were, had made a book for itself, which it could read without the assistance of the eye. At all events, it is certain that the progress he made in this part of his education, was such as is not often equalled, even by those to whom nature has given all the ordinary means of study; for he acquired so great a familiarity with the Greek language, as to be in the habit of having the works written in it read to him, and following the meaning of the author as if the composition had been in English; while he shewed his perfect mastery over the Latin, on many occasions in the course of his life, by both dictating and speaking it with the utmost fluency and command of expression.

Saunderson's acquirements were due in a great degree to his power of memory; but as this power was in reality a result of cultivation, the wonder is not materially lessened.

As is very properly observed by the writer of Saunderson's memoir, the faculty of memory, like all other accomplishments, may be invigorated by exertion to a degree of which its ordinary power seems to give no promise. In blind men this faculty is almost always powerful. Not having the same opportunities which others enjoy, of frequent or of long continued observation in regard to things with which they wish to make themselves acquainted, or of repeated reference to sources of information respecting them—their knowledge coming to them mostly in words, and not through the medium of the eye, which in general can both gather what it may desire to learn more deliberately, and recur at any time for what may have been forgotten to some permanent and ready remembrancer-they are obliged to acquire habits of more alert and watchful attention than those who are beset by so many temptations to an indolent and relaxed use of their faculties, as well as to give many matters in charge to their memory, which it is not commonly thought worth while to put it to the trouble of treasuring up. Their reward for all this is an added vigour of that mental power, proportioned to the labour they give it to perform But any one of us might improve his memory to the same extent by a voluntary perseverance in something like the same method of discipline in regard to it, to which a blind man is obliged to resort. The memory is not one of the highest faculties of the mind, but it is yet a necessary instrument and auxiliary, both in the acquisition and application of knowledge. The training, too, it may be observed, which is best adapted to augment its strength, is exactly

that which, instead of being hurtful to any of our other faculties, must be beneficial to them all.

On being brought home from school, young Saunderson was taught arithmetic by his father, and soon evinced as remarkable an aptitude for this new study as he had done for that of the ancient languages. A gentleman residing in the neighbourhood of his native village gave him his first lessons in geometry; and he received additional instruction from other individuals, to whose notice his unfortunate situation and rare talents introduced him. But he soon got beyond all his masters, and left the most learned of them without anything more to teach him. He then pursued his studies for some time by himself, needing no other assistance than a good author, and some one to read to him. Saunderson was still without a profession, or any apparent resource by which he might support himself through life, although he had already reached his twenty-fourth or twentyfifth year. His own wish was to go to the university; but the circumstances of his father, who held a place in the Excise, did not enable him to gratify this ambition. At last, however, it was resolved that he should proceed to Cambridge, not in the character of a student, but to open classes for teaching mathematics and natural philosophy. Accordingly, in the year 1707, he made his appearance in that university, under the protection of a friend, one of the fellows of Christ's College. That society, with great liberality, immediately allotted him a chamber, admitted him to the use of their library, and gave him every other accommodation they could for the prosecution of his studies. It is to be recorded,

likewise, to the honour of the eccentric Whiston, who then held the Lucasian professorship of mathematics in the university—a chair in which he ha succeeded Sir Isaac Newton, having been appointed at the express recommendation of that great man-that, on Saunderson opening classes to teach the same branches of science upon which he had been in the habit of reading lectures, he not only shewed no jealousy of one whom a less generous mind might not unnaturally have regarded as a rival and intruder, but exerted himself, in every way in his power, to promote his success. Saunderson commenced his lectures with Newton's Optics -a strange subject to be ventured upon by a person who had been blind almost from his birth. The disadvantage, however, under which Saunderson here laboured, was merely that he did not know experimentally the peculiar nature of the sensations communicated by the organ of vision. There was nothing in this to prevent him from apprehending perfectly the laws of light. He was not, it is true, able to see the rays, or, rather, to experience the sensation which they produce by falling upon the eye; but, knowing their direction, he could conceive them, or represent them, by other lines, palpable to the sense of touch, which he did possess. This latter was the way he generally took to make himself acquainted with any geometrical figure: he had a board, with a great number of holes in it, at small and regular distances from each other; and on this he easily formed any diagram he wished to have before him, by merely fixing a few pins in the proper places, and extending a piece of twine over them to represent the lines. In this manner, we are told, he

formed his figures more readily than another could with a pen and ink. On the same board he performed his calculations, by means of a very ingenious method of notation which he had contrived.

This remarkable man was also wont to perform many long operations, both in arithmetic and algebra, solely by his powerful and admirably disciplined memory. And his mind, after having once got possession of even a very complicated geometrical figure, would, without the aid of any palpable symbols, easily retain a perfect conception of all its parts, and reason upon it, or follow any demonstration of which it might be the subject, as accurately as if he had it all the while under his eye. It occasionally cost him some effort, it was remarked, to imprint upon his mind, in the first instance, a figure unusually intricate; but when this was once done, all his difficulties were over. He seems, indeed, to have made use of sensible representations chiefly in explaining the theorems of science to his pupils. In the print prefixed to his Algebra, he is represented discoursing upon the geographical and astronomical circles of the globe, by the assistance of a sphere constructed of wood. His explanations were always remarkable for their simplicity and clearness; qualities which they derived, however, not from any tedious or unnecessary minuteness by which they were characterised, but from the skill and judgment with which he gave prominence to the really important points of his subject, and directed the attention of his hearers to the particulars most concerned in its elucidation.

Saunderson's ability and success as a teacher continued