PROGRESS OF THE ATMOSPHERIC ENGINE.-SMEATON'S IMPROVEMENTS.BRINDLEY, ENGINEER OF THE BRIDGEWATER CANAL. INVENTS THE SELF-REGULATING FEEDER. JAMES WATT. -HIS DESCENT AND PARENTAGE. ANECDOTES OF HIS BOYHOOD. HIS EARLY ACQUIREMENTS, GOES TO LONDON. -RETURNS TO GLASGOW, IS APPOINTED INSTRUMENT-MAKER TO THE UNIVERSITY. OPENS A SHOP IN GLASHIS FRIENDS AND PATRONS. ADAM SMITH.- DR. BLACK. GOW. ROBERT SIMSON. — PROFESSOR ROBISON.-V - WATT'S PERSONAL CHARAC TER.INDUSTRIOUS AND STUDIOUS HABITS. - HIS ATTENTION FIRST DIRECTED TO STEAM. EXPERIMENTS ON HIGH-PRESSURE STEAM. REPAIRS AN ATMOSPHERIC MODEL.-EXPERIMENTAL INQUIRY CONSEQUENT ON THIS.-ITS RESULTS. DISCOVERS THE GREAT DEFECTS OF THE ATMOSPHERIC ENGINE. DISCOVERY BY EXPERIMENT OF THE EXPANSION WHICH WATER UNDERGOES IN EVAPORTATION. - DISCOVERS THE LATENT HEAT OF STEAM.-IS INFORMED BY DR. BLACK OF THE THEORY OF LATENT HEAT. (44.) THE atmospheric engine was brought to a state of considerable efficiency and improvement by Mr. Beighton, in 1718. effective operation of the engine. These processes, which are still necessary to the operation of the improved steam engine, appear to be wholly due to the inventors of the atmospheric engine. INVENTS THE HIS DESCENT AND PROGRESS OF THE ATMOSPHERIC ENGINE. - -SMEATON'S IMPROVEMENTS.- (44.) THE atmospheric engine was brought to a state of considerable efficiency and improvement by Mr. Beighton, in 1718. principle, and with little improvement in its structure, for half a century. Although engines of this kind continued to be extensively constructed, they were usually executed by ordinary mechanics, incapable of applying to them the just principles of practical science; and, consequently, little attention was paid to their proportions. It was not until about the year 1772, that Mr. John Smeaton, the celebrated engineer, applied the powers of his mind to the investigation of this machine, as he had previously done with such success to wind and water mills. Although he did not introduce any new principle into the atmospheric engine, yet it derived greatly augmented power from the proportions which he established for engines of different magnitudes. In 1759, Mr. James Brindley, whose name is so celebrated as the engineer of the Duke of Bridgewater's canal, obtained a patent for some improvements in the atmospheric engine. He proposed that the boiler should be made of wood and stone, with a stove or fire-place of cast iron within it, so that the fire should be surrounded on every side by water. The chimney was to be an iron pipe or tube, conducted through the boiler; so that the heated air, in passing from the fire, should impart a portion of its heat to the water. He also proposed a method of feeding the boiler, which, by self-acting machinery, would keep the water in the boiler at a fixed level, independently of any attention on the part of the engine-man. This was to be accomplished by a buoy or float upon the surface of the water in the boiler, which should communicate with a valve in the feed-pipe, so that when the level of the water in the boiler fell, the float or buoy, falling with it, would open the valve and supply the feed. It is stated, in the Biographia Britannica, that Mr. Brindley, in 1756, undertook to erect an engine at Newcastle-under-Lyne; but he is said to have been discouraged by the obstacles which were thrown in his way, and to have abandoned the steam engine. The interval between the invention of the atmospheric engine, and the amelioration it received at the hands of Smeaton, has been rendered memorable by the advent of one who was destined to work a mighty change in the condition of the human race by the application of his vast genius to the adaptation of steam power to the uses of life. (45.) JAMES WATT was born at Greenock, in Scotland, on the nineteenth day of January, in the year 1736.* The great-grandfather of Watt, a farmer in Aberdeenshire, was killed in one of the battles of Montrose. The victorious party, not thinking death a sufficient expiation for the political opinions in support of which he had fought and bled, punished him in the person of his son, by confiscating his little property. Thomas Watt, the son, thus deprived of support, was received by distant relations, and, for a time, applied himself to study, by which he was enabled, after the restoration of tranquillity, to establish himself at Greenock as a teacher of practical mathematics and navigation. He resided in the burgh or barony of Crawford's Dyke, and attained a position of sufficient respectability to be elected to the office of baron-baillie, or chief magistrate, and died in 1734, at the advanced age of ninety-two years. Thomas Watt had two sons. The elder, John, adopted the profession of his father, and was a teacher of mathematics and navigation at Glasgow: he died in 1737, at the age of fifty years. The second son, James, the father of the celebrated engineer, was, during a quarter of a century, treasurer of the town council of Greenock, and a local magistrate. He was remarked for the ardent zeal and enlightened spirit with which he discharged his public duties. His business was that of a ship-chandler, builder, and general merchant; but, unhappily, notwithstanding his active industry, he lost, in the decline of his life, by unsuccessful commercial speculations, a part of the property which he had so honourably acquired. He died in 1782, at the age of eighty-four years. JAMES WATT, to whom the world is so largely indebted for the extension and improvement of steam power, had from his birth an extremely delicate constitution. From his mother, * We are indebted for many of the anecdotes of the life of Watt to the Eloge Historique, recently published by M. Arago, who was furnished with all the documents and circumstances relating to this celebrated person which were considered proper for publication, by his son, the present James Watt, Esq., of Aston Hall, near Birmingham, and to the notes |