CONTENTS. The Thames Tunnel; Improvements in the Steam- Engine, and the Progress of Steam Navigation and Locomotion; Steamers and Railways; Lighthouses, Breakwaters, Bridges, and Diving-Bell operations; Ship-Building; Mining and Working in Metals; Lighting, Heating, and Ventilating; Gunnery; Pav- ing; Hydraulic Machines; Horology; Locks; Glass Manufacture; Millwork; Cements; Interior Decora- tion; New Processes in the Useful Arts; Printers' The Cavendish Experiment repeated; Reports on Ter- restrial Magnetism, Waves, and the Tides; Measure- ment of Time; Weights and Measures; Atmospheric Phenomena; New Researches in Sound, Light, and Electrolytic Action; Electric Light; New Batteries; Vegetable Electricity; Blasting by Galvanism; Gal- vanic and Electrical Instruments; Electro-metallurgic Processes and Apparatus; Electro-magnetic Applica- tions; Animal Electricity; the Crosse-mite, Torpedo, Animal Chemistry; Preparation of Gases; Salts; Phenomena of Heat; Chemistry of Metals; Poisons; Agricultural Chemistry; New Phenomena, Experi- ZOOLOGY: Structural Economy; Nomenclature; Mi- croscopic Researches; Mammalia, Birds, Fishes, Rep- tiles, Zoophytes, Animalcules, (Infusoria and Forami- nifera,) and Insects; New Species Page GEOLOGY: Progress of Geology: Contributions to the Glacial NOMENA: New Comets; Eclipses; Lunar Phenomena; Storms; OBITUARY of Persons eminent in Science or Art Page 252-273 274-281 282 ENGRAVINGS. Geological Section of the Artesian Well of Grenelle, at THE YEAR-BOOK OF FACTS. Mechanical and Useful Arts. COMPLETION OF THE THAMES TUNNEL.* SIR I. M. BRUNEL, F.R.S., has exhibited to the British Association†, a diagram of the exterior elevation of the Thames Tunnel, and also a representation of the machinery by which he supported the roof and sides during the process of excavation. The difficulties, (observed Sir Isambard,) were very great, and deemed insurmountable by many learned and scientific men. Indeed, the difficulties were much greater than he himself had at first conceived them to be; for the ground to be excavated was quite different from that which had been brought up with an augur in the preliminary examination of it. However, he never deemed the undertaking impracticable. It Sir I. M. Brunel then directed attention to the apparatus he had devised for sustaining the arch during the progress of the works. was upwards of 60 feet wide, by 22 feet high, divided into 12 compartments, each containing three arches, one above another. The top was horizontal. Each compartment could be moved forward or backward at pleasure, so that as the workmen excavated a few inches, the superincumbent pressure was immediately sustained by the protrusion of that part of the machinery opposite which the excavation was made. The ground was cleared away in front of each alternate division of the moveable arches, so that six were always stationary, sustaining the roof of the Tunnel; while the other six were employed in making the additional progress. Some of the strata overhead was quite dense, while part of it was in a fluid state. The workmen never advanced more than six inches at a time; and then the props were immediately introduced into the vacant place: the building up of buttresses and arches followed in the rear. During the progress of this extraordinary undertaking, five irruptions of the river had taken place. One occurred when the Tunnel was half completed. This was in consequence of the men having struck for an advance of wages; and, during the consequent delay, a very large hole opened in the top, and the water poured in. When this occurred, (said Sir Isambard,) every one had a hole for his stopper; but he could get no one to make a stopper for the hole. By that unfortunate irruption, five men were lost. However, he succeeded in stopping the * Year by year, since 1827, or during sixteen years, have we reported the progress of this stupendous work in as many volumes, viz., Arcana of Science, 11 vols.; Year-Book of Facts, 5 vols.-16. †The Association held their Twelfth Meeting, at Manchester, in the week commencing Wednesday, June 22. leakage, and in prosecuting the works, until he reached the opposite side of the river. He had now the pleasure to come before the public for the first time, and say the work was done. Many had endeavoured to discourage him, and to thwart the undertaking, but the Government had been exceedingly liberal: the Duke of Wellington, from the first moment that he had seen the plan, conceived a high notion of its practicability, and forwarded the undertaking as much as possible. In answer to a question from Mr. Roberts, Sir I. M. Brunel said that the quantity of water percolating at present, (July,) through the Tunnel, was about 60 or 70 gallons per minute. About six weeks previously, 480 gallons oozed through; the quantity had since been reduced as above; and in a short time it would entirely cease. The Tunnel was opened on August 1, for the first time, on the Wapping side of the river; when upwards of 500 visitors, of all nations, passed through, as far as the shaft on the Rotherhithe shore. The Wapping shaft is about 90 feet in height, and is surmounted by a handsome dome, which is glazed, and light and air admitted. There are two staircases, one terminating close to the western arch, and the other leading to the eastern arch. The western arch only was opened for visitors. When the Tunnel is opened as a thoroughfare for foot passengers, the toll to be charged is, we understand, to be 1d. each person. The engine and pumps, were, in August, constantly at work in the Rotherhithe shaft, to clear the Tunnel of the accumulation of water caused by the land springs. There is a culvert under the western arch, into which the waters are collected and pumped out, which keeps that side of the Tunnel always dry: as a current of air passes through the excavation, the place is rendered comfortable; and by the aid of the gas lights, which are always burning, the temperature of the atmosphere is nearly the same as it is on shore.-Times. NEW STEAM-ENGINE. THIS engine has been erected by the Messrs. Rennie, at the extensive manufactory of Mr. Thomas Cubitt, Thames-bank. It differs in no respect, as far as regards details and arrangement, from the ordinary rotative engine of Woolf. There are the two cylinders, side by side, as of old-a small one, into which the steam first passes at a high pressure from the boiler, and a larger one into which it expands, (five times); also the ponderous beam, fly wheel, rotating shaft, &c. The only difference we could observe consists in the workmanship, which is of a very superior description, and in a little better clothing, (perhaps) of the cylinders. The effective working power is stated to be equal to 60 horses, and the consumption of fuel to be no more than 2.2 lbs. per horse power per hour. So small an expenditure of fuel has never been before reached by any rotative engine, of any description; not even by the same sort of engine when in the hands of Woolf. We were assured that it was doing the same work which two or three old engines, of the cumulative power of 60 horses, had been in use to perform, and have no reason to question the fact.-Mechanics' Magazine, No. 971. STEAM-ENGINES. MR. T. WALKER, engineer, of North Shields, has patented certain improvements in Steam-engines, the object of which is to prevent the exhausting steam of one cylinder from interfering with the other cylinder while in full power; as he conceives that when the steam of one cylinder is exhausting, it will pass through the eduction-pipe to the other cylinder, where it is not wanted, and destroy, in a measure, the power of that cylinder for a time, (the quicker the engines go, the greater will be the resistance to each piston alternately by the other's exhausting steam); to avoid this, the Patentee uses separate exhausting ways, and so prevents the exhausting steam of one from interfering in the least with the other. Upon this, the Editor of the Mechanics' Magazine observes: "We really know not which to admire the most, the extreme simplicity of this invention, or the brevity of the specification, of which the above is not an abstract, but a copy.' STEAM-ENGINE INDICATOR. M. CLEMENT, the inventor of the Sillometer, has patented, both in France and this country, an instrument which indicates constantly the elasticity of the steam both in high and low-pressure engines, and the level also of the water in the boilers. This instrument may also be applied to the piston of an engine, so as to show the loss of power sustained by the steam in its way to it. A tube, similar to the Manometer, is affixed to the instrument through which the steam ascends, and is introduced into a copper or brass box placed on the deck of the vessel; and upon which a graduated dial indicates, by means of a hand, to the officer of the watch, the effects of the engine, without his having to send below to ascertain it. AMERICAN MARINE ENGINE. MESSRS. STILLMAN and Co., of New York, have constructed, for two steamers built for the Spanish Government, an excellent side-lever Marine Engine. The framing resembles that by Fawcett and Co.; the ingress and egress of the steam to and from the cylinder is regulated by spindle-valves wrought by an eccentric, the rod of which has a long nut, furnished with a right and left-handed thread, so as to shorten or lengthen the rod at pleasure. There is a common expansion valve, wrought as usual.-See Civ. Eng. and Arch. Journ., No. 57. TIMBER-BUILT STEAM-VESSELS. No. 54 of the Civil Engineer and Architect's Journal contains a complete Table of the proportions of the whole of the Timbers, with but few exceptions, used in the construction of Timber-built Steamvessels. The Editor believes this to be the first table of the kind that has appeared in print; that it will be valuable to all parties connected with steam navigation; and become a model for forming similar tables of other vessels than those specified, which are the Royal Tar, Don Juan, and the West India Mail Packets. |