had noted with scrupulous attention the effects of the expansion and contraction caused by the heat and the cold, purposes publishing one day the result of his observations."

The Breakwater in Plymouth Sound is the third splendid achievement of Mr. Rennie's genius we shall notice. "It can scarcely be called an architectural work, but is constructed on true hydrodynamical principles, and so gigantic in its dimensions and cyclopean in its structure, as to defy equally the force of the waves and the ravages of time."

As a civil engineer, Mr. Rennie before long established his reputation by the survey and execution of the Crinal and Lancaster Canals, and his talents in this department were speedily called into full play, "the rage for canals," at that time pervading every part of the kingdom, giving ample scope for his energies. In fact, the he was called to make were so numerous, surveys that, in a few years, he knew the surface of England, as it were, by heart, and could tell immediately when a canal was projected, what course it should take.

The resources of his mind were also displayed, in all their vigour, in the plans and construction of those magnificent docks which are such an ornament to the metropolis, and of the utmost utility to commerce and navigation. The London Docks, and the East and West India Docks at Blackwall, were executed from his plans and under his direction.

After mentioning several of the principal undertakings in which Mr. Rennie was engaged during the

His Fond of the society

last thirty years of his life, and which, on a rough estimate collected from his reports, did not fall short of forty millions sterling (about twenty of which were expended under his own immediate supervision), bis biographer adds,-"Indeed, few great works were carried on, either by the public or individuals, on which he was not either employed or consulted. industry was very extraordinary. of his select friends, and of rational conversation, he never suffered amusement of any kind to interfere with his business, which seldom engaged him less than twelve hours, and frequently fifteen, in the day. His conversation was always amusing and instructive. He possessed a rich fund of anecdote, and, like his old. friend James Watt, told a Scotch story admirably.

As a travelling-companion he was highly entertaining. He knew everybody on the road, and everybody knew John Rennie. Of an ardent and anxious mind, and naturally impetuous, he was gifted with the most perfect self-control, and the irritation of the moment was seen but as a light summer's cloud passing across his finely-marked features, which were on so large a scale, though blended with much mildness as well as dignity, as to obtain for his noble bust by Chantrey, when exhibited in Somerset House, the name of "Jupiter Tonans."

After instituting a comparison between Rennie and Mr. Ramsden, the writer, thus concludes: "They were both equally clear in their mode of communicating information to others, and it is sufficiently remarkable

that, in their illustrations, both of them had rarely recourse to any other instrument than a two-foot rule, which each always carried in his pocket. Many a time has the writer derived instruction from the twofoot rules of John Rennie and Jesse Ramsden. They were both equally communicative when they saw that information was desired; and nothing like professional jealousy or selfish feelings actuated either of these ingenious men, who, on the contrary, were always kind. and condescending to the more humble artists of their respective professions."

Mr. Rennie married in 1789, and had six children, of whom the two eldest, Messrs. George and John (now Sir John) Rennie, successfully followed the profession of their eminent father, who survived his wife, and, till within a few years of his death, enjoyed excellent health. He died October 16, 1821, and was buried in St. Paul's Cathedral, close to the grave of Sir Christopher Wren,

JACQUES ROUBO,

CARPENTER AND BUILDER.

Born 1739-Died 1791.

CARPENTRY is the well-known art of employing timber in the construction of edifices. It is of most general and most important use, and of the highest antiquity, and possesses much interest in relation to the fine arts. It is divided into two branchescarpentry and joinery. The first includes the larger and rougher kind of work, which has to do with the construction and stability of an edifice; joinery (called by the French menuiserie, from the menus bois, or small woods employed in that art) includes all the interior finishing and ornamental woodwork. To excellence in either of these arts a knowledge of geometry is requisite ; and hence the celebrated geometrician Monge thought it necessary to describe the art of carpentry in his "Treatise of Descriptive Geometry," and said that if circumstances had made it desirable for him to devote himself to any trade, he would have chosen that of a carpenter.

This art has made great advances in modern times: and there are numerous admirable examples of construction by various skilful artisans. In accuracy of execution and celerity and minuteness of finish, our

workmen are unsurpassed. Some also of the French have greatly excelled in works of ingenious carpentry, among whom is Philibert De Lorme, a celebrated architect in the time of Henry II., who was specially renowned for his method of constructing wooden domes. He invented a new plan of building, which consists in substituting for large pieces of timber deal boards, placed horizontally, in roofs of all dimensions. This idea he first carried out in the erection of the Chateau de la Muette.

The celebrated cupola of the Halle aux Blés at Paris, unhappily consumed by fire in 1802, was built upon this method, which possesses great advantages, especially in lightness of construction and economy of wood; for in this manner a very large roof may be raised with small logs.

This cupola was a masterpiece of art. "It was ornamented by twenty-five rays of panes of glass, producing a fine cffect. The eye beheld with astonishment this immense vault of 198 feet in height, 377 in circumference, and 100 feet from the floor of the pavement to its summit. It was impossible to conceive how the dome was sustained, divided thus between wood and glass, and apparently less than one foot in thickness."

Of the origin and construction of this work we have an account given by M. Boileau. The grain-trade had for a long time been confined to the circular galleries of the building, whilst the central open space remained unemployed. At the time of the fêtes given in honour of the birth of the Dauphin, son of