of the enlargement of a warehouse, where the flank wall, which had stood perfectly well, having been removed, and the warehouse enlarged by building another flank wall, removed further out by one bay, a range of posts was built on the foundation of the old wall, every one of which failed.

The cost of Alderman Humphrey's warehouse was about 12,000l. in all, or about 190l. to the square superficial. The cost of the restoration was about 1000/.

Twenty-third Meeting of the British Association for the Advancement of Science.*

Introductory Address on General Improvements in Mechanical Science during the past year. By W. FAIRBAIRN.-The first subject noticed by Mr. Fairbairn was Ericsson's Caloric Engine, from which so much had been expected. It was constructed, he said, on the same principle as the air engine of Dr. Stirling, invented ten years ago—the chief difference being, that the air in Ericsson's engine is passed through wire gauze to take up the heat, instead of through plates of iron. The great objection to the engine appeared to be that two-thirds of the power were wasted in passing the air through the gauze; and though it might be premature to pronounce an opinion before the results of the improvements lately effected were known, yet if so much of the power was required for taking up the heat, Mr. Fairbairn could not but think it must prove a wasteful expenditure of fuel.-The improvements that during the last year had been made in the application of the screw propeller were opening a new era in the history of our war and mercantile navy, of which the recent review at Spithead might be considered an indication. We were now in a state of transition between the paddle and the screw, and he had no doubt that in the progress of time great improvements would be made in the construction of the engines, and in their applicability to the work, which would materially economize space and power in our steam vessels.-Mr. Fairbairn next alluded to the construction of an immense steam vessel, which had been undertaken by Mr. Brunel and Mr. Scott Russell, of such vast dimensions that it would stretch over two of the largest waves of the Atlantic, and would thus obtain a steadiness of motion which would be a preventive against sea-sickness. This mammoth steamer is to be 680 feet long, with a breadth of beam of 83 feet, and a depth of 58 feet. The combined power of the engines would be that of 2600 horses. The ship is to be built of iron, with a double bottom of cellular construction, reaching six feet above the water line, and with a double deck, the upper and the lower parts being connected together on the principle of the Britannia tubular bridge, so that the ship will be a complete beam. It would thus possess the strength of that form of construction, and not be liable to "hogg," or break its back, as had been the case with other ships of great length. The double bottom would be a means of increased safety in other ways, for if by any accident the outer shell were broken, the inner one would prove effectual to keep out the water. As an addi* From the London Athenæum, September, 1853.

tional security, however, it was divided into ten water-tight compartments. The ship would be propelled by paddles and by a screw, which would be worked by separate sets of engines, so that if any accident occurred to the machinery of one, the other would be in reserve. He said he had no doubt that if properly constructed this ship would answer the expectations entertained of its capabilities and strength, and that it would form, when completed, the most extensive work of naval architecture that had ever been constructed.-The next subject to which Mr. Fairbairn adverted was the improvements making in the locomotive department of railways, particularly to an engine constructed for the southern division of the North Western Railway, from the designs of Mr. M'Connell, which was the most powerful locomotive that had yet been made for the narrow gauge. The peculiarity of construction consisted in the great length given to the fire box, in which the greatest amount of steam is always generated, and in the comparative shortness of the tubes, which were only half the usual length. The steam generated by this boiler was sufficient for any engine of 700 horse power. The engine was intended for an express train that would complete the distance from London to Birmingham in two hours. In manufacturing machinery there had also been great activity and progress during the past year, and it was gratifying, Mr. Fairbairn observed, to find accompanying this improvement in machinery a most prosperous condition in the working classes engaged in those manufactures-a prosperity which had never been equalled within his experience. He attributed this prosperous state of things to the combined operations of improvements in machinery and the removal of commercial restrictions. The improvement which he more especially noticed was that of a new combing machine of French invention, applicable alike to cotton, to flax, and to wool. It combs the fibre instead of carding it, a number of small combs being applied in succession to the cotton or flax, by which means a much finer yarn can be produced from the same material than is possible by the former processes. As evidence of the present activity and enterprise in manufacturing industry, Mr. Fairbairn mentioned the erection of a mammoth alpaca woolen manufactory, by Mr. Salt, of Saltaire, near Bradford, which was 550 feet long, 50 feet wide, and six stories high, besides offices, warehouses, and various other buildings connected with it. Their steam engines to drive the machinery would be equal to 1200 horse power, and the factory would employ upwards of 3000 hands. The cost of the whole would be upwards of 300,000l., and the enterprise was that of a single individual. Mr. Fairbairn concluded his résumé of manufacturing progress by noticing the improvements introduced by Prof. Crace Calvert, of Manchester, in the process of smelting iron by previously removing the sulphurous vapor from coal and coke. The results had proved most satisfactory, the strength of the iron produced by this process being about 40 per cent. greater than that made in the ordinary way.

Report of the Committee appointed in 1852 to prepare a Memorial to the Hon. East India Company on the Means of Cooling Air in Tropical Climates. By W. J. MACQUORN RANKINE.-In the absence of Mr. Rankine, one of the Secretaries read the Report, which was founded on experiments with apparatus invented by Prof. Smyth, described by him at a

previous meeting of the Association. The principle of the invention consists in cooling the air by expansion. The air at the temperature of the atmosphere is first compressed in a bell receiver, and the heat generated by this compression is lowered by passing the air through a number of tubes immersed in water, by which means it acquires in its compressed state the normal temperature of the atmosphere, say 90° of Fahrenheit. The air then passes into another inverted bell receiver, where it is expanded to the ordinary pressure of the atmosphere, and during this expansion it absorbs so much heat that the temperature is reduced to 60°. It is then admitted into the room to be ventilated. The compression of the air during the experiments in the first cylinder was equal to 3,2% ins. of mercury per square inch above the pressure of the atmosphere, and the refrigerator exposed a cooling surface of 1100 square feet, which was considered sufficient to reduce the temperature of the air in passing through the tubes to that of the atmosphere, viz: 90°. The Report stated that by means of this apparatus, 66,000 cubic feet of air per hour might be cooled from 90° to 60°, by a steam engine of one horse power, which is required to raise and depress the bell receiver. The advantage of cooling the air by mechanical means instead of by evaporation, was stated to be the avoidance of aqueous vapor with which the air is injuriously charged by the evaporating process.

On Reaping Machinery. By A. CROSSKILL.-Mr. Crosskill gave an historical account of the invention of reaping machines, from their use by the Romans and Gauls to the present time; with a view to show that though reaping machines had not been brought prominently to notice before the Great Exhibition, such implements had long since been invented, and that the reaping machines of Messrs. M'Cormack and Hussey were constructed on the same principles as those which had been previously made in this country. Among other English inventions of reaping machines, he mentioned one by Mr. Smith, of Deanston, in 1812, which from time to time underwent improvements, and in 1835 it worked very successfully at the meeting of the Highland Agricultural Society. After that trial it was laid aside, as British farmers did not encourage, and, during the redundance of labor, did not want such machines. In 1822, Mr. Ogle, of Remington, near Alnwick, invented a reaping machine, which appears to have served as a model for Mr. M'Cormack, as his machine is in almost every particular the same as Mr. Ogle's, a description of which was published in 1826. The same circumstances which prevented the adoption of Mr. Smith's reaping machine also caused Mr. Ogle's to be laid aside; though in America, where labor is scarce and the stalk of the corn more slender and dry, and therefore better adapted for the action of mechanical cutters, M'Cormack's reaper was soon in extensive demand. It was stated by Mr. Crosskill that about 2000 of M'Cormack's machines are annually sold in the United States, and that Hussey's is in nearly equal request in that country. The celebrity acquired by those machines in the Great Exhibition induced Mr. Bell, of Scotland, who had gained a prize in 1829 from the Highland Agricultural Society for a reaping machine, to bring his invention again into the field. In 1852 he contested with Mr. Hussey at the meeting of the Highland Society at Perth, and carried away the prize; and his reaping machine had proved victorious

on several subsequent trials. It was to this invention that Mr. Crosskill particularly directed the attention of the Section. It differs in several essential points from those of M'Cormack and Hussey. In the first place, the machine is propelled before the horses, which are harnessed to a pole in the centre of the machine, and not on one side; in the next place, the cutters act like large double edged scissors, which clip the corn as the machine is propelled into it; and a further advantage is, that it gathers the corn after it is cut without requiring a man to rake it off, which is necessary in the two other machines. The arrangement of the self-acting gatherer consists of an endless band of canvas, on to which the corn falls as it is cut, and it is then thrown on one side by a continuous motion of the canvas as the machine advances. With this machine, Mr. Crosskill stated, one acre and a half of corn per hour may be cut with two horses and one man to drive them.

In the discussion which ensued, Mr. Samuelson, the maker of M'Cormack's machines, admitted Bell's reapers cut the corn better than M'Cormack's; and that the saving of the hard work required from a man in gathering the corn was an important advantage; but the draft of M'Cormack's machines, he said, is lighter, and they are less costly. It was stated that the cost of Mr. Bell's reaper is double that of Mr. M'Cormack's or Mr. Hussey's, the one being 401., the other 20%. Mr. Crosskill stated, in reply to questions respecting the difficulties encountered in the use of reaping machines when corn is laid, that there is no difficulty in cutting and gathering laid corn, if the machines meet it inclined towards them, so that it may fall on the gathering board as it is cut. Models of the three machines were exhibited.

The Rise, Progress, and Present Position of Steam Navigation in Hull. By J. OLDHAM.-In this paper Mr. Oldham took a retrospective survey of the application of steam power to the propulsion of ships, with a view to prove that Hull has taken a prominent part in the introduction and improvement of the invention. In 1787 experiments were made in Hull, by Messrs. Furnace & Ashton, which resulted in the construction of a steamboat worked with paddles, that attracted the attention of the Prince Regent, by whom the boat was purchased; but it was soon after maliciously burnt. In 1814, the first steamboat on the Humber was established to run from Hull to Gainsborough. It was called the Caledonia, and it accomplished, under favorable circumstances of the tide, fourteen miles an hour. The first sea-going steamboat sent from Hull was in 1821; and it was supposed to be the first steamboat that plied on the east coast of England. The sea-going steamers that are now connected with the port of Hull have an aggregate tonnage of 9139, and 2749 horse power. The tonnage of the river-boats is 2218, with 1135 horse power. The other steamboats coming to Hull have a burthen of 5909 tons and 2236 horse power. There are altogether 80 steamboats trading with Hull, of which number 15 are propelled by the screw.

A discussion arose on the respective merits of the inventors of steam navigation, and the priority of their inventions; in which discussion Mr. Fairbairn, Mr. Bayley, and Mr. Thompson took part. Mr. Fairbairn said he saw the Caledonia enter South Shields, and that it was the first steamboat in the North after Henry Bell's on the Clyde. Bell, it was stated,

got the idea of his engine from Symington, and he made propositions to our Government, and to Napoleon during the temporary peace, for applying the principle to war ships; but the plan was rejected, as such a means of propelling ships was considered to be impracticable. In reference to Fulton's claim to be the original inventor of steam propulsion, Mr. Fairbairn said, that Fulton had most probably seen an account of Symington's experiments; but there could be no doubt that he had the precedence in bringing out steamboats in 1807, and afterwards more successful in 1810, when his steamboat was at work on the Hudson.

A Brief Description of Locking & Cook's Rotary Valve Engine, and its Advantages. By G. LOCKING.-In this engine a metal disk, with three apertures, slowly rotating on a flat surface, with corresponding openings connected with the boiler and the cylinders, supplies the place of the ordinary slide valves. Rotary motion is given to the valve by a vertical shaft, on which there is a pinion that is worked by a cog-wheel on the shaft of the engine. The two bearing surfaces are ground steam-tight, and an outer casing serves to confine the steam, as in the common slide valve. The advantages said to be gained by this arrangement are the diminution of friction and a more ready means of cutting off the steam and of reversing the engine. As the rotary valve has a continuous slow motion, the inconvenience and friction occasioned by the rapid reciprocating action of the slide valve is avoided. Among other advantages of this contrivance, it was stated that it costs less, is less liable to get out of order, and occupies less room. Mr. Cook, the inventor, is a working nechanic in Hull.

Mr. Fairbairn, Mr. Roberts, Mr. Hancock, and other gentlemen expressed themselves favorably of the invention, and at the conclusion of the business, the members of the Section paid a visit to Messrs. Locking & Cook's works, to inspect a steam engine constructed on this principle in action.

On a new Thermostat for regulating Temperature and Ventilation. By W. SYKES WARD.-This apparatus consists of a series of flat circular hollow cases, about one foot in diameter and one inch deep, attached together in their centres. Each case contains a small quantity of sulphuric ether, which is readily affected by change of temperature. The cases, comprising about six, are suspended one under the other, and to the lowest one is attached a weight by a cord that passes over an eccentric pulley. On an increase of temperature, the ether expands, and the weight falls down, and it is drawn up again by the pressure of the atmosphere on the external disks of the cases when the air is cooled. By connecting the weight with the ventilators of a conservatory, or other building, the temperature can be thus regulated to any required degree by a previous adjustment of the apparatus.

On a Compound Safety Valve, and On an Improved Tubular Boiler. By JAMES HOPKINSON.

On Railway Accidents by Collision, and their Prevention. By the Rev. Dr. SCORESBY.-After adverting briefly to the numerous railway accidents caused by collision, Dr. Scoresby proposed as a means of diminishing, if not of preventing, such occurrences, the adoption of a more frequent and effectual communication by electric telegraph. His plan is