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JESSE RAMSDEN.

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This eminent mathematical and as he had invented his famous dividing tronomical instrument-maker was the machine, and brought the sextant son of an innkeeper, at Salterhebble, such perfection as never to give more near Halifax, in Yorkshire, and born than half a minute of uncertainty. The there in 1735. He was educated first | value of his labours, in this respect, to at Halifax free-school, and afterwards science, may be conceived from the fact

an academy in Craven, York that the same instrument generally in shire, at which latter he made con use among astronomers might fail by siderable proficiency in geometry and five minutes, and thus occasion, in the algebra, and took great delight in these longitude, an error of fifty nautical destudies. On leaving school, he was put grees. The merit of his dividing. apprentice to a clothier, at Halifax, for machine will be understood when it is three years, at the expiration of which stated, that a sextant can be divided period, he entered the service of an with it in twenty minutes; and, in other manufacturer of the same town, smaller works, it may be said to in the capacity of clerk. This situation have superseded, in a great measure, he exchanged, in his twentieth year, for the use of beam compasses. For bringa similar one in a London house ; but, ing this machine to perfection, the after he had stayed there two years, his board of longitude gave Mr. Ramsden inclination for mechanical pursuits so a premium of £1,000, and caused a deforcibly revived, that he quitted the scription of it, with a plate, to be pubclothiery line altogether, and bound lished, in 1777, which edition was, himself apprentice to Mr. Burton, a unfortunately, burnt, The theodolite celebrated thermometer and barometer was so far improved by Mr. Ramsden, maker, and engraver and divider of as to serve, not only for taking angles, mathematical instruments. On the ex but also for measuring heights and piration of his apprenticeship, he hired distances. He made one for General himself

, at the rate of twelve shillings Roy, of such accuracy, though only of a-week, as a journeyman workman, to eighteen inches radius, as not to admit one Cole, with whom he subsequently an error of a single second. His alteraentered into a partnership, but soon tion in barometers for measuring the effected a dissolution, and opened a beight of mountains is another triumph workshop on his own account. He was of his skill. By marking at the bottom not long in gaining employment from the line of the level, and looking at some of the most eminent mathematical the top to the contact of the index with instrument-makers of the day, and thus the summit of the mercury, he made it becoming intimate with Dollond, mar- possible to distinguish the hundredth ried his daughter about the year 1765. part of a line, and to measure heights At this time he was not only master of within a foot. We may also here menthe lathe and file, but of the art of grind- tion his superior execution of an elecing glasses, and had formed the design of trical machine ; a manometer, for mea. examining every astronomical instru- suring the density of the air; assaying ment in use, with a view of correcting balances, which turn with a ten-thouthose well designed, but imperfectly sandth part of the weight used; the executed, and of proscribing those which optic rectangle, prismatic eye.glasses, a were defective, both in principle and dynameter, pyrometer, and a reflecting construction.

ohject-glass micrometer. Accounts of Mr. Ramsden kept a shop in the his successful improvement of the last Haymarket, from 1766 till 1774, when instrument were published in the he removed to Piccadilly, and carried Transactions of the Royal Society for on business there for the remainder of 1779 and 1785; and, in the following his life. As early as the former year year, Mr. Ramsden was elected a mem

ber of that body, an honour his modesty rant, and he is said to have demonhad, for some time previously, led him strated to M. de Lalande, that to attain to decline. In 1794, he was elected a to the utmost degree of precision of member of the Imperial Academy of which observation is susceptible, the Sciences at Petersburgh ; and, in 1795, quadrant must be renounced entirely. he was presented with the annual gold The perfection to which he brought his medal of the Royal Society.

instruments recommended him to such But the great works of the subject of constant employment, that, although he our memoir are yet to be mentioned ; kept sixty men, he was unable to exethese are the equatorial, the transit in cuie all his orders; and persons who strument, and the mural quadrant. A succeeded in purchasing, were conpatent was granted him for the first- sidered fortunate. He sold them, howmentioned instrument, in which his ever, at a cheaper rate than any other chief improvements were, his rejection artist in the same line, in London, and of the endless screw, which, by pressing was enabled to leave but a very small on the centre, destroyed its precision; fortune behind him. His intense apand his placing the centre of gravity on plication to business at length injured the centre of the base, causing all the his health, and having removed to movements to take place in every direc- Brighton, for the benefit of the sea air, tion. Upon one of these instruments, he died there, on the 5th of November, the greatest that had ever been at 1800. tempted, he was employed nine or ten His character has been drawn in a years. It was made for Sir George very high strain of panegyric, by the Shuckburgh, and in so admirable a Rev. L. Dutens, at the close of a memanner, that observations could be moir of him in Aikin's Biography. He made nearly within a second. We have appears to have been above the middle not space for a detail of the manner in size, with a countenance full of sweetwhich he improved the transit instru ness and intelligence, frank and cheerment; in this, as in others, exactness ful in manners, and full of humour, was his grand aim, and with that view even to playsulness, among his intione of his inventions was, a method for mate friends.

His chief failing appears superseding the use of the spirit level. to have been a facility of temper, which In the mural quadrant he has distin- induced him to break his promises to guished himself by the exactness of his absent, in favour of present, friends; a divisions, and by the manner in which graver defect in character than his he has furnished the planes, by work. eulogists or biographers seem to have ing them in a vertical position. A proof considered. His temperance, simpliof the perfection to which he brought city of dress, and frugality, might have this instrument, is to be seen in one of pointed him out as a miser, but for the six feet, which he made for the Duke of total heedlessness of expense with which Marlborough, at Blenheim. “ For this," he pursued any new idea for the imsays one of his biographers, “ which is provement of his instruments, and his as beautiful as it is perfect, Mr. Rams utter indifference to all views of pecuden invented a method of rectifying the niary profit. His whole life was dearc of ninety degrees, respecting which voted to his business, and it was less in an able astronomer had started some the hours of relaxation than of illness, difficulties; but with a horizontal thread, that he found time to make himself and with a thread and plummet, form- completely master of the French laning a kind of cross, which does not guage. His manual dexterity was on a touch the quadrant, he showed him that par with his scientific knowledge; and there was not an error of a single it is said that he could, with his own second in ninety degrees; and that the hands, have begun and finished every difference arose from a mural quadrant single part of his most complicated inof Bird, in which the arc of ninety struments. Of his skill in astronomical degrees contained several seconds too mechanism the preceding memoir will much, and which had not been verified have furnished sufficient proof, nor need by 80 exact a method as this.” It we, perhaps, add, that as an optician he seems, however, that Mr. Ramsden was perfect; yet, to use the words of preferred the whole circle to the quad- the writer above-mentioned, " While

Europe, in every corner, repeated his fault with it ;" and if any improvement name with respect, it was, to a great appeared to be feasible, he spared no portion of his countrymen, scarcely expense to effect it. It is said to have known, but as that of a very idle spec been the custom of Ramsden to retire, tacle-maker; and he thus worked for in the evening, to what he considered every foreign nation with a marked the most comfortable corner in the house, predilection over his own countrymen.” the kitchen fire-side, and there, with

When he occasionally sent for a his drawing implements, on the cable workman to give him directions con before him, a cat sitting on one side, cerning what he wished to have done, and a certain portion of bread, butter, he first shewed the recently finished and a small mug of porter placed on plan, then explained the different parts the other, draw some plan for torming of it, and generally concluded by say: a new instrument, or for the improveing, “ Now see, man, let us try to find ment of one already made.

DANIEL CHARLES SOLANDER.

This distinguished naturalist was In 1768, Mr. (afterwards Sir Joseph) born in the province of Nordland, in Banks proposed to Dr. Solander to Sweden, where his father was minister, accompany him and the celebrated on the 28th of February, 1736. He Captain Cook, in a voyage round the received both his scholastic and me world, in pursuit of discoveries in his dical education at Upsal, at the uni favourite science; and permission being versity of which place, he appears also granted him, by the trustees of the to have taken his doctor's degree. British Museum, to retain his appointAfter having made a tour to Russia, he ment during his absence, he prepared was advised, by Linnæus, whose pupil to depart. * Such a companion." it is he had been, to visit England; and he, observed, in the introduction to Captain accordingly, set out for that country Cook's first voyage, “ Mr. Banks conin 1760. On his way thither, he hap- sidered an acquisition of no small impened to go on board a ship of war, for portance ; and, to his great satisfaction, the purpose of seeing a 'friend who the event abundantly proved that he formed part of the crew, when the was not mistaken." In the course of vessel was suddenly ordered to sail to this voyage, he encountered many the Canary isles; a circumstance which dangers in his ardour for botanical disprotracted the period of his arrival in coveries, and, in particular, during his England in a manner he had little ascent of a mountain in Terra del anticipated. On reaching the metro. Fuego, in search of Alpine plants; on polis, he presented a letter of introduc which occasion, Mr. Banks and himself iion, from Linnæus, 10 Mr. Peter were near losing their lives. AccordCollinson; which gentleman, in 1762, ing to the Dictionnaire Historique, the recommended him to the trustees of subject of our memoir had a salary of the British Museum, as a person, who £400 a-year during his absence, but had made natural history the study of on what account is not stated: he had his life, and was particularly qualified no public appointment, and was proto draw up a catalogue of that part of bably indebted to the munificence of their collection. In 1764, he was Mr. Banks for his pecuniary resources elected a fellow of the Royal Society; at this time. In 1773, he was appointed and, in 1765, one of the assistants to one of the under-librarians in the British the British Museum, in the department Museum, and continued to hold this of natural history. In the following situation till his death, which was year, he drew up, for Mr. Brander, brought on by apoplexy, on the 16th the scientific description of his Hamp- of May, 1782. shire fossils, entitled Fossilia Han In testifying to the merits of toniensia, &c.

Dr. Solander as a naturalist, Dr.

Pulteney speaks of his arrival in this minds, and dispelled the prejudices of country as an era of importance in the many who had been averse towards it." progress of botany, and as a great help The last part of this account is conto the establishment of the Linnæan firmed by the statement of one of his system in England. “ His name,” he intimate friends, who says that, to a observes, " and the connexion he was very extensive knowledge, he added a known to bear, as the favourite pupil of mode of communication, not only rehis great master, had of themselves markable for its readiness, but for so some share in exciting a curiosity which peculiar a modesty, that he contrived led to information; while his perfect almost to appear to receive instruction acquaintance with the whole scheme, when he was bestowing it in the most enabled him to explain its minutest ample manner. In person, he was parts, and elucidate all those obscurities short, fair, and fat, with small eyes, with which, on a superficial view, it and a good-humoured expression of was thought to be enveloped. I add countenance. The only publication to this, that the urbanity of his manners, known of his, is a paper in the Philoand his readiness to afford every as- sophical Transactions, entitled Account sistance in his power, joined to that of the Gardenia (Jasminoides), though clearness and energy with which he he is said to have written several others. effected it, not only brought conviction Linnæus gave the name of Solandra to of its excellence to those who were in- a genus of plants, in honour of his clined to receive it, but conciliated the friend.

JAMES WATT.

James WATT, the son of a mer- engineer. He soon acquired a high rechant, was born at Greenock, in Scot- putation; and in making surveys and land, on the 19th of January, 1736. estimates for canals, harbours, bridges, He received the first part of his educa- and other public works, was as exten: tion at a school in his native place, and sively employed in his own country, as completed it at home, by his own dili- Brindley had been in England. gence. The science of mechanics, for His attention to the employment of which he afterwards became so famous, steam, as a mechanical agent, had been, formed, at an early age, his favourite in the first instance, excited by witnessstudy; and, in conformity with his de- ing some experiments of his friend Mr. sire,' he was, at the age of eighteen, John (afterwards Dr.) Robison, and he apprenticed to a mathematical instru: had also made some experiments him. ment-maker, in London, The bad self, with a view of ascertaining its exstate of his health, however, which had pansive force. It was not, however, before retarded his progress at school, till 1763-4 that he began to devote compelled him to returri

, after a year's himself seriously to the investigation of stay in the metropolis, to Scotland. the properties of steam, and to ascerThis was all the instruction he ever re- tain those results upon which his fame ceived in the business for which he was was to be founded. An examination of intended, yet he must have attained Newcomen's engine, a model of which considerable skill, as, in 1757, he, at had been sent him to repair, revived all the recommendation of some relations, his former impressions respecting the commenced the practice of it, at Glas. radical imperfections of the atmospheric gow, and was immediately appointed machine, to the improvements of which mathematical instrument-maker to the he now ardently devoted himself. One college. He continued to hold this of his first discoveries was, that the situation till 1763, when he married, rapidity with which water evaporates, left his apartments in the university, for depends simply upon the quantity of a house in the town of Glasgow, and heat which is imbibed, and this again commenced the profession of a general on the extent of the surface of the

vessel containing the water, exposed second radical imperfection of Newcoto the fire. He ascertained also the men's engine, namely, its non-employquantity, of coais necessary for the ment, for a moving power, of the evaporation of any given quantity of expansive force of the steam. The water, the heat at which it boils under effectual way, it occurred to him, of various pressures, and many other par preventing any air from escaping into ticulars never before accurately deter the parts of the cylinder below the mined.

piston, would be to dispense with the He now proceeded to attempt a use of that element above the piston, remedy of the two grand defecis of and to substitute there likewise the Newcomen's engine-ihe necessity of same contrivance as below, of alternate cooling the cylinder before every stroke steam and a vacuum. This was to be of the piston, by the water injected into accomplished by merely opening comit; and the non-employment of the munications from the upper part of the machine, for a moving power, of the cylinder to the boiler, on the one hand, expansive force of the steain.

On

and the condenser on the other; and account of the first defect, a much forming it, at the saine time, into an more powerful application of heat, than air-tight chamber, by means of a cover, would otherwise have been requisite, with only a hole in it to admit the rod was demanded for the purpose of again or shank of the piston, which might, heating the cylinder, when it was to be besides, without impeding its freedom refilled with steam. To keep this vessel, of action, be padded with hemp, the therefore, permanently hot, was the more completely to exclude the air. IL grand desideratum ; and Watt at length was so contrived, accordingly, by a hit upon an expedient equally simple proper arrangement of the cocks, and and successful. His plan was to estab the machinery connected with them, lish a communication, by an open pipe, that while there was a vacuum in one between the cylinder and another vessel, end of the cylinder, there should be an the consequence of which would be, admission of steam into the other; and that when che steam was admitted into the steam so admitted now served, nor the former, it would flow into the latter, only by its susceptibility of sudden conso as to fill that also. Supposing, then, densation, to create the vacuum, but that the steam should here only be con also, by its expansive force, to impel the densed, by being brought into contact piston. with cold water, or any other conve These were the principal fundamental nient means, a vacuum would be pro- | improvements in an engine, which has duced, into which, as a vent, more since been brought to such perfecsteam would immediately rush from tion of action and power, as to form the cylinder; this steam would also one of the most triumphant eras in the be condensed; and so the process would history of human ingenuity. Instead go on, till all the steam had left the of entering into all the subsequent concylinder, and a perfect vacuum had trivances which Wati invented, we been effected in that vessel, without so cannot give a better idea of his splendid much as a drop of cold water having success, than by quoting the language of touched or entered it.

The separate

a recent writer. " In the present state vessel alone, or the condenser, would of the engine, it appears a ihing alınost be cooled by the water used to condense endowed with intelligence. It reguthe steam; which, instead of being an lates, with persect accuracy and unievil, would tend to quicken and pro- formity, the number of its strokes in a mote the condensation. Experiments given time, counting or recording them, fully confirmed Watt in these views; moreover, to tell how much work it has and the consequence was, not oniy a done, as a clock records the beats of its saving of three-fourths of the fuel pendulum ; it regulates the quantity of formerly required to feed the engine, steam admitted to work; the briskbut a considerable increase of its power. ness of the fire, the supply of water to

In overcoming this difficulty, Watt the boiler; the supply of coals to the was conducted to another improvement, fire ; it opens and shuts its valves with which effected the complete removal absolute precision as to time and manof what we have described as the ner; it oils its joints; it takes out any

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