(Abraham), an eminent mathematician, mechanist, and astronomer, was descended from an ancient family at Little-Horton, near Bradford, in the West Riding of Yorkshire, where he was born about the year 1611. At a proper age he was put apprentice to a merchant at Manchester; but his genius led him so strongly to the study of mathematics, both theoretical and practical, that he soon became uneasy in that situation of life. By the mutual consent, therefore, of his master and himself, though not altogether with that of his father, he quitted the business of a merchant. Upon this he removed to Liverpool, where he gave himself up wholly to the study of mathematics, astronomy, &c.; and where, for a subsistence, he opened a school, and taught writing and accounts, &c.
He had not been long at Liverpool when he accidentally fell in company with a merchant or tradesman visiting that town from London, in whose house it seems the astronomer Mr Flamsteed then lodged. With the view therefore of becoming acquainted with this eminent man, Mr Sharp engaged himself with the merchant as a book-keeper. In consequence he soon contracted an intimate acquaintance and friendship with Mr Flamsteed, by whose interest and recommendation he obtained a more profitable employment in the dockyard at Chatham; where he continued till his friend and patron, knowing his great merit in astronomy and mechanics, called him to his assistance, in contriving, adapting, and fitting up the astronomical apparatus in the Royal Observatory at Greenwich, which had been lately built, namely, about the year 1676. He was principally employed in the construction of the mural arch; which in the compass of 14 months he finished to greatly to the satisfaction of Mr Flamsteed, that he speaks of him in terms of the highest praise. According to Mr Smeaton, this was the first good and valid instrument of the kind; and Mr Sharp the first artist who cut accurate and delicate divisions upon astronomical instruments. At the time this instrument was constructed, Mr Flamsteed was 30 and Mr Sharp 25 years of age.
These two friends continued together for some time, making observations on the meridional zenith distance of the fixed stars, sun, moon, and planets, with the times of their transits over the meridian; also the diameters of the sun and moon, and their eclipses, with those of Jupiter's satellites, the variation of the compass, &c.
Mr Sharp assisted Mr Flamsteed also in making a catalogue of near 3000 fixed stars, with their longitudes and magnitudes, their right ascensions and polar distances; with the variations of the same while they change their longitude by one degree.
But from the fatigue of continually observing the stars at night, in a cold thin air, joined to a weakly constitution, he was reduced to a bad state of health; for the recovery of which he desired to retire to his house at Horton; where, as soon as he found himself on the recovery, he began to fit up an observatory of his own; having first made an elegant and curious engine for turning all kinds of work in wood or brass, with a mandrill for turning irregular figures, as ovals, rosettes, wreathed pillars, &c. Besides these, he made himself most of the tools used by joiners, clockmakers, opticians, mathematical instrument makers, &c. The limbs or arcs of his large equatorial instrument, sextant, quadrant, &c. he graduated with the nicest accuracy, by diagonal divisions into degrees and minutes. The telescopes he made use of were all of his own making, and the lenses ground, figured, and adjusted with his own hands.
It was at this time that he assisted Mr Flamsteed in calculating most of the tables in the second volume of his Historia Coelestis, as appears by their letters, to be seen in the hands of Mr Sharp's friends at Horton. Likewise the curious drawings of the charts of all the constellations visible in our hemisphere, with the still more excellent drawings of the planisphere both of the northern and southern constellations. And though these drawings of the constellations were sent to be engraved at Amsterdam by a masterly hand, yet the originals far exceeded the engravings in point of beauty and elegance; these were published by Mr Flamsteed, and both copies may be seen at Horton.
The mathematician, says Dr Hutton, meets with something extraordinary in Sharp's elaborate treatise of Geometry Improved (in 4to, 1717, signed A.S. Philomath): viz., by a large and accurate table of segments of circles; its construction and various uses in the solution of several difficult problems, with compendious tables:
(a) The beautiful red Turkey leather is dyed with cochineal prepared in the same manner. Professor Gmelin junior, in the second part of his Travels through Russia, explains the herb tchagana by artemisia annua, having doubts been deceived by the appearance the plant acquires after it has been dried. Besides, this artemisia is found only in the middle of Siberia, and never on the west side of the Irtisch. for finding a true proportional part; and their use in these or any other tables exemplified in making logarithms, or their natural numbers, to 60 places of figures; there being a table of them for all primes to 1100, true to 61 figures. 2d, His concise treatise of Polyhedra, or solid bodies of many bases, both the regular ones and others: to which are added twelve new ones, with various methods of forming them, and their exact dimensions in furlongs, or species, and in numbers; illustrated with a variety of copperplates, neatly engraved by his own hands. Also the models of these polyhedra he cut out in boxwood with amazing neatness and accuracy. Indeed few or none of the mathematical instrument makers could exceed him in exactly graduating or neatly engraving any mathematical or astronomical instrument, as may be seen in the equatorial instrument above mentioned, or in his sextant, quadrants, and dials of various sorts; also in a curious armillary sphere, which, beside the common properties, has moveable circles, &c., for exhibiting and resolving all spherical triangles; also his double sector, with many other instruments, all contrived, graduated, and finished, in a most elegant manner, by himself. In short, he possessed at once a remarkably clear head for contriving, and an extraordinary hand for executing, anything, not only in mechanics, but likewise in drawing, writing, and making the most exact and beautiful schemes or figures in all his calculations and geometrical constructions.
The quadrature of the circle was undertaken by him for his own private amusement in the year 1699, deduced from two different series, by which the truth of it was proved to 72 places of figures; as may be seen in the introduction to Sherwin's Tables of Logarithms; that is, if the diameter of a circle be 1, the circumference will be found equal to $3\pi^4 + \frac{1}{2} \pi^5 - \frac{1}{3} \pi^6 + \frac{1}{4} \pi^7 - \frac{1}{5} \pi^8 + \cdots$. In the same book of Sherwin's may also be seen his ingenious improvements on the making of logarithms, and the constructing of the natural lines, tangents, and secants.
He also calculated the natural and logarithmic sines, tangents, and secants, to every second in the first minute of the quadrant; the laborious investigation of which may probably be seen in the archives of the Royal Society, as they were presented to Mr Patrick Murdoch for that purpose; exhibiting his very neat and accurate manner of writing and arranging his figures, not to be equalled perhaps by the best penman now living.
Mr Sharp kept up a correspondence by letters with most of the eminent mathematicians and astronomers of his time, as Mr Flamsteed, Sir Isaac Newton, Dr Halley, Dr Wallis, Mr Hodgson, Mr Sherwin, &c., the answers to which letters are all written upon the backs, or empty spaces, of the letters he received, in a shorthand of his own contrivance. From a great variety of letters (of which a large chaff remain with his friends) from these and many other celebrated mathematicians, it is evident that Mr Sharp spared neither pains nor time to promote real science. Indeed, being one of the most accurate and indefatigable computers that ever existed, he was for many years the common resource for Mr Flamsteed, Sir Jonas Moore, Dr Halley, and others, in all sorts of troublesome and delicate calculations.
Mr Sharp continued all his life a bachelor, and spent his time as recluse as a hermit. He was of a middle stature, but very thin, being of a weakly constitution. He was remarkably feeble the last three or four years before he died, which was on the 18th of July 1742, in the 91st year of his age.
In his retirement at Little Horton, he employed four or five rooms or apartments in his house for different purposes, into which none of his family could possibly enter at any time without his permission. He was seldom visited by any person, except two gentlemen of Bradford, the one a mathematician, and the other an ingenious apothecary; these were admitted, when he chose to be seen by them, by the signal of rubbing a stone against a certain part of the outside wall of the house. He duly attended the dissenting chapel at Bradford, of which he was a member, every Sunday; at which time he took care to be provided with plenty of halfpence, which he very charitably suffered to be taken singly out of his hand, held behind him during his walk to the chapel, by a number of poor people who followed him, without his ever looking back, or asking a single question.
Mr Sharp was very irregular as to his meals, and remarkably sparing in his diet; which he frequently took in the following manner. A little square hole, something like a window, made a communication between the room where he was usually employed in calculations, and another chamber or room in the house where a servant could enter; and before this hole he had contrived a sliding board; the servant always placed his victuals in this hole, without speaking or making any noise; and when he had a little leisure, he visited his cupboard to see what it afforded to satisfy his hunger or thirst. But it often happened, that the breakfast, dinner, and supper, have remained untouched by him, when the servant has gone to remove what was left—for deeply engaged had he been in calculations.
SHARPS in flour, the finer part of what we have denominated POLLARDS. See that article, Suppl.