for which he took out a patent, consisted in the substitution of lime for potash. His patent right was, however, resisted by certain of the bleachers of Lancashire, and was set aside by the verdict of a jury, on the grounds that the patent included a mode of 'bucking' with quicklime and water, which was not a new invention; and because one part of the patent was not new, the whole of the claim must be set aside. By this decision the use of liquid chloride of lime in bleaching was thrown open to all; and through an unfortunate error of expression in describing his process, Mr. Tennant was deprived of the fruits of a laborious investigation extending over a period of several years. This subsequently caused a strong feeling of sympathy to be manifested for him by many of the bleachers of Lancashire, who, as an expression of their grateful acknowledgment, presented him with a service of plate, which he accepted. Mr. Tennant, however, in accordance with the character of his original design, determined to press onward with his discoveries, and to bring, if possible, his first invention to a still more practical issue. He therefore adopted a new method, and at length completed and secured by patent a process for impregnating quicklime in a dry state with chlorine, which proved perfectly successful; this, his second patent, remained uncontested, and he lived to secure a large pecuniary reward.

Mr. Tennant's discoveries, together with the introduction of sodaash or 'British soda,' in place of potash, greatly facilitated and cheapened the process of bleaching, while the introduction of mechanical appliances and the power of the steam-engine_superseded the previous laborious operations by hand. The result has been that the same amount of bleaching is now performed in as many days as was formerly performed in weeks, while the price has been reduced from 7s. 6d. (1803) to 6d. (1861) for a piece of cloth of 28 yards.

In the year 1800 Mr. Tennant removed from Darnly to St. Rollox, Glasgow, where he commenced business as a large manufacturing chemist, taking into partnership Mr. Charles Mackintosh, Mr. William Cowper, and Mr. James Knox. During the remainder of his life Mr. Tennant devoted himself with energy to the forwarding of his business, and ultimately caused his manufactory to become the largest and most extensive of its kind in Europe. He also took considerable interest in the politics of the day. His principles were those of an intelligent and liberal-minded reformer, and he was long looked up to as one of the leading men of his party, although the least tainted by mere party spirit or selfishness. Mr. Tennant was likewise conspicuous in his promotion of many public undertakings. He took a deep interest in the furtherance of the railway system; the Garnkirk and Glasgow Railway may be said to owe its origin and completion almost entirely to him, while his invincible industry and perseverance contributed greatly towards the establishment of

the Edinburgh and Glasgow Railway. He was a great friend of George Stephenson's, and was present with him at the opening of the Liverpool and Manchester Railroad when the unfortunate accident occurred which resulted in the melancholy death of Mr. Huskisson.

Mr. Tennant died rather suddenly, in his seventy-first year, at his house in Abercrombie Place, Glasgow. He was possessed of a constitutional nervousness, rather remarkable in one of a large and healthy frame, allied to a peculiar sensitiveness to the beautiful. In after life he would often talk with pleasure of his youthful reminiscences of the poet Burns, who was at 'that time on terms of considerable intimacy with his family. Mr. Tennant was an earnest and indefatigable promoter of economical and educational improvement; an uncompromising friend of civil and religious liberty; while his own inborn energy of character and clear intellect placed him among the foremost of those men who, by uniting science to manufactures, have at once extended their fields of action, and entitled their occupations to be classed among the ranks of the liberal professions.-The Progress of Science and Art as developed in the Bleaching of Cotton, by Henry Ashworth, Paper read before the British Association at Manchester, September 5, 1861; and, Particulars communicated by the Family.

THOMAS THOMSON, M.D., F.R.S.

Born April 12, 1773. Died July 2, 1852.

Dr. Thomas Thomson, Regius Professor of Chemistry in the University of Glasgow, who exercised a remarkable influence in the development and extension of the science of chemistry during the present age, was born at Crieff, in Perthshire. He received his early education at the parish school of that place, and after remaining for a time under the care of Dr. Doig, of Stirling, went to the University of St. Andrews, where he remained for a period of three years. Thomson entered upon his medical studies at the University of Edinburgh, and during the session of 1795-96 attended the lectures of the celebrated Dr. Black, who first awoke in him the latent taste for that science of which he was destined to become so bright an ornament. In 1796 he became connected with the Encyclopædia Britannica, for an early edition of which he wrote the articles— Chemistry, Mineralogy, Vegetable Substances, Animal Substances, and Dyeing Substances, &c. These articles formed the basis of his

system of chemistry, which he published at Edinburgh in the year 1804, in four volumes, and afterwards greatly enlarged and improved as the demand for the book increased. Dr. Thomson commenced delivering a series of lectures on chemistry at Edinburgh in 1800, which were continued with increasing popularity until 1810. Meanwhile he invented the system of chemical symbols now generally adopted by all men of science (with variations as the time demands), and without which chemical language would be unintelligible. He was also the first to open a laboratory in Great Britain for practical manipulation in chemistry. In 1810 he published his 'Elements of Chemistry,' and in 1812 visited Sweden, and on his return wrote a description of that country. The following year to this Dr. Thomson started in London the Annals of Philosophy,' a scientific journal, which he continued to edit until the year 1822, and which a few years afterwards was merged in the 'Philosophical Magazine.' He also about this time conducted for the Board of Excise a series of investigations on brewing, which formed the basis of Scottish legislation on that subject.

In the year 1817 Thomson was elected lecturer on chemistry in the University of Glasgow, and in the following year received the title of Professor. This chair he held until his death, being assisted in his latter years by his nephew and son-in-law, Dr. R. D. Thomson. When Dalton had worked out his grand discovery of the Atomic Theory, he communicated the result of his researches to Thomson, who at once perceived the value and importance of the discovery, and in the year 1807 was the first to publish it to the world. He gave a sketch of this grand theory in the third edition of his System of Chemistry;' and we are chiefly indebted to the labours of Professor Thomson, conjointly with Dr. Henry of Manchester, and Dr. Wollaston, for luminous views on this important subject. In 1825 Dr. Thomson wrote, in two volumes, 'An Attempt to Establish the First Principles of Chemistry by Experiment.' In 1830-31 he published his 'History of Chemistry, a work which has been described as a masterpiece of learning and research. In 1836 appeared his 'Outlines of Mineralogy and Geology;' and in 1849 he issued his last work, 'On Brewing and Distillation.'

Thomson performed in science, and its history and literature, a very great amount of valuable labour, and acquired a distinguished reputation both as an original discoverer, and as a practical teacher of his favourite science. He died in 1852, at the age of seventynine, and has left behind him a son who bears his name, now (1860) superintendent of the East India Company's Botanic Gardens at Calcutta, and one of the most distinguished scientific botanists of the day.-Encyclopædia Britannica, Eighth Edition.-English Cyclopædia. London, 1858.

RICHARD TREVITHICK.

Born April 13, 1771. Died April 22, 1833.

Richard Trevithick, inventor of the first high pressure steamengine, and the first steam-carriage used in England, was born in the parish of Illogan, in Cornwall. He was the son of a purser of the mines in the district, and although he received but little early education, his talents were great in his own special subject, mechanics. When a boy he had no taste for school exercises, and being an only son, was allowed by his parents to do much as he pleased; so that most of his time was passed either in strolling over the mines amidst which he lived, or in working out schemes which had already begun to fill his youthful imagination, seated under a hedge, with a slate in his hand. Trevithick was a pupil of William Bull, an engineer practising at that time in Cornwall, employed in erecting Watt's engines, and who afterwards accompanied Trevithick to South America. When he had attained the age of twentyone, Trevithick was appointed engineer to several mines, a more responsible situation than the one held by his father, who, on hearing of his son's appointment, expressed great surprise, and even considered it his duty to remonstrate with the gentlemen who had proposed the appointment. About this period (in 1792) he was also employed to test one of Hornblower's engines, and even before this, had, with the assistance of William Bull, constructed several engines which did not come under Watt's patent. Trevithick's duties, as engineer, at this time, frequently required him to visit Mr. Harvey's iron foundry at Hayle, who was in the habit of inviting him to his house; this ultimately resulted in his becoming attached to Mr. Harvey's daughter, to whom he was married on the 7th of November, 1797. After his marriage Trevithick lived at Plane-an-quary in Redruth for a few months, then at Camborne for ten years. From about 1808 to 1810 he resided in London; but after his unfortunate failure in attempting to tunnel the Thames, returned to Penponds in the parish of Camborne, where he lived for five or six years, at the house of his mother, afterwards living at Penzance, from which town he sailed for Peru on the 20th October, 1816. While residing at Camborne, Trevithick influenced perhaps by the success of Murdock's model steam-carriage, determined to build one adapted to ordinary road traffic. One Andrew Vivian supplied the pecuniary means and joined him in the project, for which, on its completion, a patent was taken out in 1802, and in the same year a small one was erected at Marazion, which was worked by steam of at least thirty pounds on the square inch above atmospheric pressure.* Their steam-carriage presented the appearance of an ordi

* The specification of this patent gives likewise the first mention (we believe)

nary stage-coach on four wheels, having one horizontal cylinder, which, together with the boiler and fire-box, were placed at the back of the hind axle. Mr. Michael Williams, late M.P. for Cornwall, in a letter to Mr. E. Watkins, dated the 5th of January, 1853, mentions having been present at the first trial of Trevithick's locomotive, and says "the experiments made on the public road close by Camborne were perfectly successful, and although many improvements in the details of such description of engines have been since effected, the leading principles of construction and arrangement are continued, I believe, with little alteration in the magnificent railroad engines of the present day." After making several satisfactory trials in the neighbourhood of Plymouth, Trevithick and Vivian exhibited their invention publicly in London, first at Lord's Cricket-ground, and afterwards on the spot of ground now occupied by Euston Square.* At this latter place, however, Trevithick, influenced by some curious whim, suddenly closed the exhibition on the second day, leaving hundreds waiting outside in a state of great wrath. Mrs. Humblestone, an old inhabitant of London, who at that period used to keep a shop near to the present Pantheon, Oxford Street, relates that she well remembers witnessing a public trial of Trevithick's steam-carriage. On this occasion the shops were shut, no horses or carriages were allowed in the streets, and the roofs of the houses in the neighbourhood were crowded with people, who hurraed and waived their handkerchiefs as the 'steam monster' was seen coming along Oxford Street at a rapid pace.†

Two years afterwards Trevithick constructed the first successful railway locomotive, which was used on the Merthyr Tydvil Railway in the year 1804. This engine had an eight-inch cylinder, of four feet six inches stroke, placed horizontally as at present, and working on a cranked axle; while, in order to secure a continuous rotatory motion, a fly-wheel was placed on the end of the axle. When we add to this, that the fly-wheel was furnished with a break, that the boiler had a safety-valve or a fusible plug beyond the reach of the engineer, and that the patent includes the production of a more equable rotatory motion-" by causing the piston rods of two cylinders to work on the said axis by means of cranks at a quarter of a turn asunder "-it is scarcely too much to say that nothing material was added to the design of the locomotive until the invention of the on record of oscillating engines. Sir John Rennie, F.R.S., in his address to the Institution of Civil Engineers, in 1846, mentions the following passage:"Even the objection of extra friction, however, if tenable, is obviated by the vibrating cylinder described in Trevithick and Vivian's patent, in 1802; patented by Whitty in 1813, and by Manby in 1821, by whom the first engines of the kind were constructed."

An eye-witness, who is still living, relates that on one of these trials he saw Trevithick's steam-carriage proceeding at the rate of twelve miles an hour.

Mrs. Humblestone (1861) is now eighty-one years of age, and is residing in

the neighbourhood of Edgware Road.