Part 17

In 1784 he established himself in London, and commenced work by the erection of the Albion Mills near Blackfriars Bridge, Boulton and Watt, who had the direction of the steam-engines, having, in accordance with the advice of Professors Robison and Black, entrusted to him the execution of the millwork. Mr. Watt, in his notes to Professor Robison's account of the steam-engine, says that "in the construction of the millwork and machinery, they derived most valuable assistance from that able mechanician and engineer, Mr. John Rennie, then just entering into business, who assisted in placing them, and under whose direction they were executed." He also adds that the machinery, which used to be made of wood, was here made of cast iron, and considers that this was the commencement of that system of millwork which has proved so beneficial to this country. After executing this undertaking, Rennie was employed on the flour mills at Wandsworth, and the rolling and triturating mills at the Mint. His mills, and particularly his water wheels, were regarded as models of perfection, while in all hydraulic works he was the worthy successor of Smeaton. From this time until his comparatively early death in 1821, Rennie was constantly employed on various large and splendid undertakings, among which his bridges occupy an important place. Of these structures the finest is the Waterloo Bridge over the Thames, begun in 1809 and finished in 1817. It is built of Aberdeen granite, and consists of nine equal semi-elliptical arches of 20 feet span, with a level roadway 45 feet wide from outside to outside of parapet, which adds greatly to its beauty. This bridge was opened to the public by the Prince Regent, who offered at the time to confer upon Mr. Rennie the honour of knighthood; this offer, however, he declined. London Bridge, which he designed but did not live to execute, was finished by his sons, Mr. George and Sir John Rennie. It is built of the finest blue and white granite from Scotland and Devonshire, and consists of five semi-elliptical arches, two of 130, two of 140, and the centre one of 152½ ft. span, being perhaps the largest elliptical arch ever attempted. The beautiful stone bridge over the Tweed at Kelso, and those at Musselburgh and New Galloway, were also designed by him. When speaking of the first-named of these bridges, Mr. Rennie used often playfully to declare, that he considered himself a benefactor to his country, inasmuch as one of his earliest public works was to build a bridge across the Tweed! The iron bridges which he executed are, the one at Boston, over the Witham, with a span of 100 feet; and the noble bridge at Southwark, over the Thames, begun in 1815 and opened in 1819. The latter consists of three circular arches of equal curvature, the centre one having a span of 240, and the other two of 210 feet. The total weight of iron in the structure was 5780 tons, and the entire cost, including approaches, &c., 800,000l.

The improvement of harbours and the construction of docks occupied much of Mr. Rennie's attention, and in these operations his diving-bell apparatus was of peculiar value. Smeaton was the first who used the diving-bell effectually for building with stone under water; the machine he employed for that purpose was, however, very defective, and could only be used in certain situations. But Rennie, by improvements in the instrument itself, and in the machinery by which its movements could be regulated, was enabled to carry on masonry, and the foundations of sea-walls, piers, and quays, as well under water as above it. He first employed his apparatus in 1813, in building the East Pierhead at Ramsgate, the foundations of which were 17 feet below low water at spring tides. It was afterwards used in founding the pierheads and outer walls of the harbours at Holyhead, Howth, and Sheerness, and other works under his direction. Amongst the numerous wet docks introduced at Liverpool in 1716, and since constructed at almost all the principal sea-ports in the kingdom, Mr. Rennie executed the London Docks, and those at Leith, Dublin, Hull, and Greenock, and also the East and West India Docks, in conjunction with Jessop and Ralph Walker. He also constructed the harbours of Queensferry, Berwick, Howth, Holyhead, and that at Kingston, the largest attempted in this country. At the low water of spring tide, the depth of this harbour was 26 feet, while the area enclosed amounted to 250 acres. The breakwater at Plymouth for protecting the Sound from the swell of the sea was likewise designed by him and Mr. Whitby, and was the first and largest example of a detached breakwater in this country. One of the most useful works executed by Mr. Rennie was the drainage of the great Fen district bordering upon the rivers Trent, Witham, New Welland, and Ouse, and extending 60 miles in length by 25 in breadth. In the carrying out of this great work, by which many hundreds of square miles were rendered productive, and the salubrity of the district improved, he was assisted by Mr. Telford and his son, Sir John Rennie. The chief canals of which he was engineer are the Kennet, Avon, Crinan, Rochdale, and Lancaster. The naval dockyards at Portsmouth, Plymouth, Chatham, and Sheerness, also attest his skill as an engineer. The latter was a mere quicksand 40 feet deep, mixed with mud and the wrecks of old ships; the whole of which was excavated, and a magnificent basin constructed with a surrounding wall of granite, with which three large and commodious dry docks communicated. Several magnificent works of great public utility were proposed to the government by Mr. Rennie but never executed. The most remarkable of these is his design for a great naval arsenal on the Thames at Northfleet, intended as a substitute for the imperfect naval establishments on the river. It was to consist of six capacious basins, with an area of 600 acres within the walls, and to comprehend machinery for every operation connected with the naval science. The estimated cost of this noble plan was eight millions, which might have amounted to ten or eleven millions, but would even then have been a measure of economy compared with the vast sums expended on the old establishments on the Thames and Medway.

Before closing the present brief account of this celebrated engineer's life and works, his lighthouse on the Bell Rock must not be passed by without notice. Like the Eddystone, it was built of stone; commenced in 1806, and finished in 1811, it still remains an enduring monument of the skill of its architect.

Until within a few years of his death Mr. Rennie enjoyed robust health, but he was cut off in the sixty-first year of his age after a few days' illness. He was buried in St. Paul's Cathedral, his remains being interred near to those of Sir Christopher Wren.--Encyclopædia Britannica.--North British Review, Feb., 1861.--Mechanics' Magazine, September 20 and November 22, 1861.

FRANCIS RONALDS, F.R.S.

Francis Ronalds was born in London, in the year 1788. From a very early period in life he devoted himself to the advancement of electrical science, a course he has consistently pursued during a large portion of his life, which has not yet we are glad to be able to state drawn to its close. He is the inventor of an electric telegraph, electrical machine, electrometer, a new mode of electrical insulation, a pendulum doubler, an electric clock, several meteorological and magnetical instruments and other mechanical contrivances. The year 1816, however, marked Mr. Ronald's great achievement in the advancement of electric telegraphs. During that year he was the first to demonstrate that they could be practically and unerringly applied to the passage of messages through a long distance. Well aware of the difficulties arising from imperfect insulation, which had baffled his predecessors, Mr. Ronalds secured the success of his apparatus both by employing better means of insulation than had hitherto been adopted, and also by making use of a form of apparatus which should of itself be capable of supplying any loss of electricity which might arise from defects in the insulation. Mr. Ronalds placed his telegraph wire in glass tubes surrounded by wooden troughs lined with pitch, which were placed in a trench dug in his garden at Hammersmith. He also suspended eight miles of wire by silken cords from a wooden frame erected on his lawn, through which he was enabled to successfully pass messages except in wet weather, the cords not being protected from the wet.

Mr. Ronald's peculiar form of apparatus may be thus briefly described:--At two stations were placed two clocks, with a dial with 20 letters placed on the arbour of the second-hand; in front of each of these dials was placed a screen with a small orifice cut in it so that, as the dial revolved, only one letter could be seen at a time. The clocks were made to go isochronously, and were started at the same instant with the same letter appearing on the dial through the orifices of each of the screens, both dials, therefore, as they revolved, would of course continue to show similar letters. This formed the readable index of his telegraph; means of communication between the two stations were produced in the following manner:--connected with each end of the telegraph wire, and placed in front of the clocks, were two pith ball electrometers, upon which a constant stream of electricity, produced from an ordinary frictional machine, operated and consequently kept in a state of divergence, except when a letter on the dial was to be denoted; the electricity was then partially discharged by breaking the connection, the pith balls in a measure collapsed, and the distant observer was thereby informed to note down the letter then visible through the orifice on the screen. In this way letter after letter might be denoted and intelligence of any kind conveyed. All that was absolutely required for the success of Mr. Ronald's telegraph was, that the clocks should go isochronously during the time intelligence was being transmitted, for, by a preconcerted arrangement, both clocks might be easily started at the same letter upon a given signal. The attention of the distant observer was called by the explosion of gas by means of an electric spark. In 1823, Mr. Ronalds published a full description of his telegraph, in a work entitled, 'Descriptions of an Electrical Telegraph, and of some other Electrical Apparatus.'

In 1825, Mr. Ronalds invented a perspective tracing instrument, to facilitate drawing from nature or from plans and elevations, an account of which he published in 1828 in a work entitled, 'Mechanical Perspective.' With this machine he was enabled some years afterwards (in 1835), assisted by Dr. Blair, to procure exact perspective projections taken from given noted stations, of the Celtic remains at Carnac in Brittany. The result of these researches was published by Mr. Ronalds and Dr. Blair in 1836, and was entitled, 'Sketches at Carnac; or, Notes concerning the present state of the Celtic Antiquities in that and some of the adjoining Communes.' In connection with this tracing apparatus, he likewise contrived a hexipod staff used for a support, and which has been much employed for the support of instruments requiring great steadiness, such as telescopes, theodolites, cameras, &c. In the year 1843 he became the first and honorary director of the Kew Observatory, and while occupying this office he supplied the observatory with various new contrivances, for which he received a government reward from the special service fund, and a small pension from the civil list. The most considerable of these contrivances were his atmospheric electrical conductor and its appendages, adopted at the Greenwich, the Madrid, and the Bombay magnetic observatories; his photo-barograph, and two photo-thermographs, adopted at the Radcliff observatory, Oxford; his photo-electrograph, and three photo-magneto-graphs. Besides the writings above-mentioned, Mr. Ronalds is the author of an article in the Philosophical Magazine of 1814, entitled, 'On Electro-galvanic Agency, employed as a moving power, with descriptions of a Galvanic Clock;' and other articles in the same journal, detailing his original experiments to illustrate the relations of quantity and intensity in the electric pile. He also wrote four Reports on the Kew observatory, which were fully illustrated and printed in the reports of the British Association for the years 1845-50-51 and 52; and one paper in the Philosophical Transactions on 'Photographic Self-registering Meteorological and Magnetical Instruments,' written in 1846 and printed in the year following. In 1856 Mr. Ronalds published in French, at Paris, a summary of these reports, with some additions, entitled, 'Descriptions de quelques Instruments Meteorologiques et Magnetiques,' intended to explain his instruments at the French exhibition.

Mr. Ronalds is now (April 1864) residing at Battle in Sussex, and during the latter years of life has spent much time and part of his small pension, in collecting and collating an electric library, which might be conveniently available for the advancement of his favourite science, and prove worthy of presentation or bequest to some British public institution, so as to form the nucleus of one which might approximate possibly to a complete electrical library.--From particulars derived from authentic sources.

COUNT RUMFORD (SIR BENJAMIN THOMPSON), LL.D., V.P.R.S.,

MEMBER OF THE ROYAL INSTITUTE OF FRANCE, ETC.

Born March 26, 1753. Died Aug. 21, 1814.

Benjamin Thompson, the founder of the Royal Institution, and more generally known by the title of Count Rumford, which he afterwards acquired, was born at Woburn in Massachussets. His ancestors appear to have been among the earliest colonists of this district, and in all probability came originally from England.

Thompson's father died while his son was a mere infant, and two or three years afterwards his mother married a second husband, Josiah Pierce, also a resident at Woburn. As soon as young Thompson was able to learn his letters he was sent to the school of his native town, kept by a Mr. John Fowle, where he remained until his eleventh year, when he joined the school of a Mr. Hill at Medford. Here Thompson made such advances in mathematics and astronomy as to be able to calculate eclipses. At the age of thirteen he was bound apprentice to Mr. John Appleby, a respectable merchant in Salem, the second town in point of size in Massachussets. His occupations with Mr. Appleby were principally those of a clerk in the counting house, but he appears to have had sufficient leisure to extend his reading in scientific subjects, and also to indulge a taste, he began to exhibit, for designing and engraving. At this time he was likewise occupied with a contrivance for solving the famous problem of perpetual motion, but was ultimately made to see the fallacy of his expectations, by the arguments of an old friend and schoolfellow, Loammi Baldwin, who induced him to attempt-something more practicable though less magnificent.

At this period, 1767, the differences between Great Britain and her American colonies were beginning to assume a serious aspect, and there ensued such a stagnation of trade at Salem and other towns, that Mr. Appleby, having no further occasion for the services of a clerk, was glad to give up to young Thompson his indentures, and allow him to return to Woburn. For the next two or three years Thompson's course of life seems to have been wavering and undecided. At one time he appears to have had thoughts of entering the medical profession, for he remained during some months under the tuition of Dr. Hay, a physician in Woburn, and entered zealously upon the study of anatomy and physiology.

In 1770, however, he resumed his mercantile avocations in the capacity of a clerk at a dry goods store at Boston, kept by a Mr. Capen, and was thus engaged during the famous riots which took place in that town, on the attempt to land a cargo of tea from a British vessel, contrary to a resolution of the colonists against admitting British goods. These disturbances caused Mr. Capen's business to decline as Mr. Appleby's had formerly done, and Thompson was again obliged to return to Woburn. He now seriously turned his attention to the acquisition of scientific knowledge, and in company with his friend Baldwin attended a course of lectures on experimental philosophy delivered at Harvard College, instituting at the same time many experiments of his own, some of which proved the germs of valuable conclusions published in after life. In particular may be mentioned a course of experiments which he began in order to ascertain and measure the projectile force of gunpowder.

Thompson, though still only in his seventeenth year, had now acquired a certain amount of reputation; he was also endowed with much natural grace and many personal advantages, which subsequently proved the means of gaining him access to the first circles in Europe.

Towards the close of the year 1770 he was invited by Colonel Timothy Walker, one of the most important residents in the village of Rumford, now Concord, in New Hampshire, to take charge of an Academy in that place. Two years later, at the age of twenty, he married Mrs. Rolfe, a colonel's widow possessed of a considerable fortune. After his marriage Thompson took his place as one of the wealthiest inhabitants of the district in which he resided, mixing with the best society the colony afforded. Among others he made the acquaintance of the governor John Wentworth, who, wishing to attach to the British party so influential a colonist, gave Thompson the commission of major in a regiment of the New Hampshire Militia, in which a vacancy had occurred. This act of attention, while gratifying to Thompson, procured him much ill-will from the officers already in the service, and over whose head he had been promoted.

From this period he began to be unpopular in his native country. He was represented as a friend of Great Britain, and an enemy to the interests of the colonies. The public hatred of him at length rose to such a height, that he only escaped by flight from the ignominy of being tarred and feathered in the open streets. Leaving his wife and an infant daughter, Thomas first took refuge in his native town of Woburn, and then proceeded to Charlestown where he remained for several months. From Charlestown he went to Boston, at which place he was well received by General Gage and the officers of the British army at that time in garrison at Boston. Returning in the spring of 1775 to Woburn, he again ran the risk of being tarred and feathered, but was saved by the interference of his friend Baldwin.

The commencement of open hostilities between the Colonists and the British troops in May, 1775, made Thompson's position still more critical, and finding that he could not overcome the prejudice felt against him, he came to the desperate resolution of quitting his native country, and leaving his wife and child. To effect this he first escaped to Boston, where he remained, with his friend General Gage, until the evacuation of the town by the British troops, when he embarked on board the Scarborough, and set sail for England, with despatches from General Gage to Lord George Germain, the British Secretary of State for Colonial Affairs.

Although Thompson arrived in England the bearer of gloomy tidings, and sustaining the equivocal character of a deserter from the American cause, he soon showed that he was a man capable of commanding his fortune anywhere. The capacity in which he had come over introduced him to various public men who were both struck by his abilities and charmed by his manners. But a short time elapsed after his arrival before he was offered a post in the Colonial Office, and four years after, in 1780, was raised by his patron Lord Germain to the post of under secretary for the colonies, an instance of rapid promotion which, considering the circumstances in which the subject of it stood, is almost unexampled.

The income and consequence which Thompson derived from this office gave him admission to the highest metropolitan circles, and he had thus opportunities not only of becoming known, but also of exercising his inventive mind in many pursuits not immediately connected with his official duties. Fertility of resources, and a disposition to propose improvements in all departments, appear to have been his most striking characteristics, and it was probably this ready genius for practical reform in everything which came under his notice, that recommended him so much to public men. While engaged generally in a variety of matters, Thompson was at the same time following out certain specific lines of scientific investigation. His experiments on the heat caused by friction, deduced from the boring of cannon, are among the best we possess.

In 1777 he made some curious and interesting experiments on the strength of solid bodies, which were, however, never published. In 1778 he employed himself in further experiments on the strength of gunpowder and the velocity of military projectiles; and these were followed up by a cruise of some months in the Channel fleet, where he proposed to repeat his experiments on a larger scale. He communicated the result of his researches on this subject, in several papers, to the 'Philosophical Transactions' of the Royal Society, of which he became a member in the last-mentioned year.

On the retirement of Lord George Germain from office, Thompson was sent out to New York in the year 1781, with the royal commission of major, afterwards changed to that of lieutenant-colonel, charged with the task of organizing an efficient regiment of dragoons out of the broken and disjointed native cavalry regiments which had been fighting on the royalist side. This regiment was, however, of no avail; peace was concluded between Great Britain and the United States, and Colonel Thompson on his return to England obtained leave of absence to travel on the Continent. In crossing from England to France, it happened that he had as a fellow-traveller the celebrated historian Gibbon, who, in some subsequent correspondence, spoke of him as "the soldier, philosopher, statesman--Thompson."

While on his way to Vienna, Thompson attended a review of the garrison of Strasbourg, and, attracting general attention by his superb English horse and uniform of colonel of dragoons, became introduced to the notice of Prince Maximilian, nephew and presumptive heir of the Elector of Bavaria. This prince was agreeably impressed by the manners and address of Thompson, and furnished him with letters of introduction to his uncle, the Bavarian Elector. When Thompson arrived at Munich (so great seems to have been his power of conciliating favour), he was offered, on his first interview with the elector, an important situation at court, if he would take up his residence there. After a little delay, Thompson accepted this offer, conditional upon receiving permission from his Britannic Majesty. Proceeding to London to obtain the required consent, he was very favourably received by George III., who conferred on him the honour of knighthood, and allowed him to retain his title of lieutenant-colonel, together with the half-pay attached to it.

Towards the close of the year 1784, Sir Benjamin Thompson, at the age of thirty-one, took up his residence at Munich, and filled the posts of aide-de-camp and chamberlain to the Elector; being thus connected both with the military and civil service of the Bavarian dominions. Into these twin branches of government he soon introduced many important and salutary reforms; he reorganized the Bavarian army, and introduced many improvements into the art of agriculture as practised in that part of Europe; he also took wise and effectual measures for the suppression of mendicancy, and for the ameliorization of the condition of the poor at Munich, introducing among them some excellent plans for the economization of food and fuel.

While investigating this latter subject, Sir Benjamin paid particular attention to the construction of grates and fireplaces, and to the scientific properties of light and heat. He so improved the methods of heating apartments and of cooking food, as to produce a saving in the precious element of heat varying from one-half to seven-eighths of the fuel previously consumed; so that it was wittily said, that he would never rest satisfied until he had cooked his dinner with his neighbours' smoke. To him also is the honour due of being the first to explain the manner in which heat is propagated in fluids. In requital of these important services to the Bavarian state, Thompson was decorated with two orders of Polish knighthood; he also received the appointments of member of the Council of State and lieutenant-general in the army, was created commander-in-chief of the general staff, minister of war, and superintendent of the police of the electorate, and was finally, in 1790, raised to the dignity of Count of the Holy Roman Empire, by the title of Count Rumford, in memory of the American village where he had formerly officiated as schoolmaster. The scientific part of the community also showed their esteem for him, by electing him a member of the Academies of Munich and Manheim; and in 1787, when on a visit to Prussia, he was chosen a member of the Academy of Sciences at Berlin.

When the advance of the French army under Moreau compelled the Elector to quit his capital, Count Rumford was for a short time placed at the head of the Regency, and in this capacity succeeded in the arduous task of freeing the Bavarian state from foreign invasion. This important service increased Rumford's reputation with the Elector and the people, and he was permitted to settle one-half of the pension which he enjoyed on his daughter, to be paid during her lifetime.