in Table LXXIX. of the effect of employing different kinds of pig-metal, show that at a mean temperature of 570° those trials gave a strength of 60398 lbs., whence the diminution is .0869.

Of 224 B, at 520° the tenacity was 58451. On the same bar, four cold experiments gave a mean strength of 54934, which by calculation gives a maximum of 63267, and a consequent diminution of .0761.

On a survey of the preceding discussions it will be seen that in determining the maximum belonging to each point of fracture, it has been necessary to resort sometimes to experimental, and sometimes to calculated results, but that in several cases the two operate as checks upon each other.

On attempting to extend the principle to trials made below the temperatures already cited, we are liable to encounter an ambiguity in the results, owing to the fact that the maximum tenacity is not generally to be obtained without having carried the previous temperatures to about 550° or 600°, and the tension to nearly or quite that of the original strength of the metal when cold.

In projecting into a curve as in Plate X. the data furnished by the experiments above described, and of which a synopsis is given in the following table, it becomes at once apparent that what was conjectured with respect to copper, in regard to a point of inflection, is here presented in a manner to admit of no uncertainty. Indeed it could hardly be otherwise, when we consider that the melting point of wrought iron, at which all tenacity must be overcome, is doubtless situated above 3000°; and by the experiments of Clement and Desormes, is as high as 3945°. Now it appears that at a temperature no higher than about 1050° onehalf of the strength is destroyed; at 1240°, two-thirds; and at 1317°, seven-tenths of the maximum tenacity is overcome.

The following table exhibits the observed temperatures, and corresponding tenacity of the metal with the calculated, or experimental maximum of strength,-the ratio of the observed diminution to the maximum tenacity, and the irregularity of the metal in parts of the original strength dinary temperatures.

at or

PROGRESS OF THE THAMES TUNNEL.

A meeting of the Proprietors of the Thames Tunnel took place on the 5th instant, at which the Directors "reported progress," both as regards works and pecuniary matters. Upon the latter point we cannot trust ourselves to say a word; and upon the former we must allow the "Report" to speak for itself. After a few general prefatory observations, like in substance to many of those which have preceded it, lamenting difficulties, and expressing certainty of their being overcome, citing the approbation of the Duke of Wellington, Earl Grey, and other members of successive Governments in the scheme, they proceed :

"It had been found by experience that the attempt to continue the work of excavation when the soil was peculiarly loose and disturbed was disadvantageous, inasmuch as the cost of the work was enhanced without a proportionate progress, and that an occasional suspension of this portion of the work was even favourable to its ultimate progress, inasmuch as during that time the ground became naturally consolidated, and more easily and safely excavated. In order however to prevent any loss to the Company, whenever it was necessary to stop the advance of the shield, Mr. Brunel proposed to commence the work on the north side of the river, with a view to ensure employment for the men above, when their labours were suspended below ground. Thus, though the work was to be suspended in one part, it was intended to be progressing in another, and the whole establishment was to be kept in constant employment, to the manifest advantage of the public and the Proprietors.

"This plan was, however, abandoned with regret, upon its being considered to be inconsistent with the condition under which the public money was granted, viz., that "the most hazardous part of the work" should be first finished before any other portion was commenced.

47.7

"Your Directors, therefore, after the most careful and anxious deliberation, determined to adopt the second plan proposed by Mr. Brunel, and which was in partial operation at the period of the last General Meeting. It was not in perfect and general operation for some short time afterwards, and previous to which the river once more forced its way into the works. The delay, however, on this as on former occasions was inconsiderable, and the week after the irruption the work proceeded.

"This plan consisted of three principal features, viz:

"1st, To divert the navigation from that part of the river immediately over the mining operations.

2ndly,To gain the command of that part of the river, without interruption, and to be thus enabled to load and cover its bed,both over the works in progress and in advance of them; and to compress this artificial bed, directly over the shield, by groun ing upon it at every fall of the tide, a vessel when ballasted, of about 900 tons burthen. And,

"3dly, To make alterations in the auxiliary parts of the shield, still further to add to its security and power.

"Your Directors are now enabled to report the decided success which has attended this plan throughout the past year, and which has indeed exceeded their most sanguine anticipations.

"The brickwork of the tunnel has been advanced, since the last meeting, 90 feet, and is now within 60* feet of low water mark; and if the same rate of progress continues, which there is every reason to expect, low water mark will be reached in the course of the autumn.

"It will be clear to those who are best acquainted with the work, that when this is accomplished the most hazardous portion of the tunnel will be completed; and that however novel, and even bold, the work which then remains to be done, in order to realise the original design, yet its completion becomes comparatively safe and easy, and calculable within a reasonable time.

"Your Directors, in their report of last year, acknowledged the great and liberal assistance afforded by the Board of Admiralty on very many occasions; and the generous and cordial assistance they had at all times received from the Corporation of the City of London, the Navigation Committee, and Harbour Masters, and which the Directors continue to receive. These authorities enabled the engineer to, fully and entirely to

Since this Report was read to the General Meeting, five feet have been excavated; the distance to low water is therefore only 55 feet.

his satisfaction, to perfect and enter upon the plan he was constrained to follow, and which was in strict accordance with the Treasury Minute.

"Thus the Directors have now the gratification to meet the Proprietors, after so many years of anxiety and delay, with the most reasonable hope, of having but one more Annual Meeting intervene between the speedy termination of all the peculiar hazards and difficulties of the undertaking; and such an advance of the works as shall bring them near to the time when their anxious trust will be discharged, by the final completion of this most arduous enterprize."

LIST OF ENGLISH PATENTS GRANTED BETWEEN THE 23rd OF FEBRUARY AND THE 27th OF MARCH, 1839.

George Augustus Kollmann, of the Friary, St. James's Palace, professor of music, for certain improvements in the mechanism and general construction of pianofortes, being an extension of former letters patent for the term of seven years. February 23.

Charles Louis Stanislas Baron 'Heurtéloupe, of Queen Ann-street, for certain improvements in firearms, and in the balls to be used therewith. February 23; six months to specify.

Thomas Pratt, of South Hylton, Durham, mechanic, for an improved capstan and winch for purchasing or raising ships' anchors, without the application of a messenger, in which there is no fleeting or surging, and for drawing or working of coals and other articles and things out of coal and other mines; and also for the drawing and working on railroads, by drawing, pulleys, with flat or round ropes. February 23.

James Russell, of Handsworth, Stafford, gas-tube manufacturer, for certain improvements in manufacturing tubes for gas and other purpose, being an extension, for the term of six years, of former letters patent, granted to Cornelius Whitehouse, and assigned by him to the said James Russell. February 26.

Moses Poole, of Lincoln's Inn, gentleman, for improvements in constructing and applying boxes to wheels. February 28; six months.

Moses Poole, of Lincoln's Inn, gentleman, for certain improvements in tanning. February 28; six months.

John Leigh, of Manchester, surgeon, for an improved mode of obtaining carbonate of lead, commonly called white lead. February 28; six months.

Richard Whytock, of Edinburgh, manufacturer, and George Clink, of the same, place, colour maker, for further improvements in the process and apparatus for the production of regular figures or pattterns in carpets and other fabrics, in relation to which a patent was granted to the said Richard Whytock, on Sept. 8, 1832, and generally in the mode of producing party colours on yarns or threads of worsted, eotton, silk, and other fibrous substances. March L; six months.

Moritz Platow, of 19 Poland-street, Oxford street, engineer, for improvements in pumps or engines for raising or foreing liquitis. March 6; six months.

John Dickson, of Brook-street, Holborn, engineer, for certain improvements in rotatory steam engines. March 6; six months.

Auguste Vietor Joseph Baron d'Astia, of Millman-street, Bedford-row, for improvements in pro

ducing or affording light, which he denominates a solar light. March 6; six months.

Walter Hancock, of Stratford, in the county of Essex, engineer, for certain improvements in steam boilers and condensers. March 6; six months.

George Robert d'Harcourt, of Howland-street, Fitzroy-square, gentleman, for improved arti ficial granite, stone, marble, or concrete, in which said Invention neither asphaltic nor bituminous substances are used. March 6; six months.

William Vickers, of Firshill, Sheffield, merchant, for a mode of obtaining tractive power from carriage wheels under certain circumstances. March 6; -six months.

John Clark, of Upper Thames-street, London, engineer, for a new or improved form or construction of a leg and foot for propelling carriages on rail or common roads, and a new combination or arrangement of machinery for locomotive carriages, by means whereof the weight of the load to be carried is rendered applicable as a part of the power for moving or propelling the carriage on which it is supported or rests. March 6; six months.

Charles Schafhautl, of Cornhill, London, gentleman, for an improved method of smelting copper March 6; six months.

ore.

Orlando Jones, of Rotherfield-street, Islington, accountant, for improvements in the manufacture of starch, and the converting of the refuse arising in or from such manufacture, to divers useful purposes. March 6; six months.

George Holworthy Palmer, of Surrey-square, Old Kent-road, C. E., and George Bertie Paterson, of *Hoxton, engineer, for certain improvements in gas meters. March 6; six months.

Thomas Horton, of Princes-end, Stafford, boilermaker, and Thomas Smith, of Horseley heath, in the same county, mine agent, for certain improvements in the making or constructing of chains for pits, shafts, mines, or other purposes. March 6; six months.

Edward Ford, of Liverpool, builder, for certain improvements in conducting the manufacture of salt cake or sulphate of soda, and hydrochloric or other acids and alkalies, or other chemical processes wherein deleterious vapours are given off, and in the erection of furnaces and works connected therewith. March 8; six months,

Josias Christopher Gamble, of Saint Helens, Lancaster, manufacturing chemist, for improvements in apparatus for the manufacture of sulphate of soda, muriatic acid, chlorine, and chlorides. March 14; four months.

Elisha Haydon Collier, late of Boston, but now of Globe Dock Factory, Rotherhithe, C. E., for improved machinery for manufacturing nails. March 14; six months.

Christopher Nickels, of York-road, Lambeth, for Improvements in the modes of manufacturing of fabrics from linen, woollen, silk, and other fibrous materials. March 15, six months.

Richard Lamb, of David.street, Southwark, gentleman, for improvements in apparatus for supplying atmospheric air in the production of light and heat. March 16,six months.

Alexander Francis Campbell, of Grest Plumstead, Norfolk, Esq., and Charles White, of Norwich, mechanic, for certain improvements in ploughs. March six months.

Thomas Henry Ryland, of Birmingham, screw manufacturer, for an improved manufacture of screws for wood, in iron, brass, or any mixed metals, commonly known as "wood screws." March 18; six months.

John Ruthven and Morris West Ruthven, of Edinburgh, civil engineers, for improvements `in boilers for generating stoum, economizingtfuel, and propelling vessels by steam or other power, and ventilating vessels, and which may be applied to mines and buildings. March 20; six months.

Edward 'Law, of Downham Road, Kingsland, gentleman, for certain improvements in evaporat

ing sea water and other fluids, and in the manufacture of salt. March 20; six months.

Joseph Amesbury, of Burton Crescent, surgeon, for a certain apparatus for the support of the human body. March 20; six months.

Andrew Smith, of Princes-street, Leicestersquare, for certain improvements in the manufac ture of ropes, for cables and other purposes to which ropes are applicable. March 20; six months. George Nelson, of Milverton, Warwick, chemist, for a new or improved method, or new or improved methods of preparing gelatine, which has the properties of or resembles glue. March 23; six

months.

Thomas Fisher Salter, of Great Hallingbury, Essex, farmer, for an improved machine for winnowing and dressing corn and other grain. March 23; six months.

Richard Roberts, of Manchester, for an improvement or certain improvements of,in,or applicable to the mule billy jenny stretching frame, or any other machine or machines, however designated or named, used in spinning cotton wool or other fibrous substances, and in which either the spindles recede from and approach the rollers or other deliverers of the said fibrous substances, or in which such rollers or deliverers recede from and approach the spindles; being an extension for the term of seven years of former letters patent. March 26.

Henry Montagu Grover, of Boveney, Buckingham, clerk, for improvements in brewing by the use of a material not hitherto so used. March 26; six months.

Joseph Lees, jun., of Manchester, calico printer, for certain improvements in the art of printing calicoes, muslins, and other woven fabrics, and in certain processes connected therewith. March 26; six months.

Edmund Butler Rowley, of Manchester, surgeon, for an improved steam engine applicable to locomotive, marine, and stationary purposes. March 26; six months.

Elisha Hale, of Leadenhall-street, London, for improvements in umbrellas and parasols. March 27; six months.

William Newton, of Chancery-lane, for certain improved machinery for cutting and removing earth, which machinery is applicable to the digging of canals and the levelling of ground for railroads or ordinary roads and similar earth works. March 27; six months.

LIST OF SCOTCH PATENTS GRANTED BETWEEN THE 22nd APRIL AND THE 22nd MAY, 1839.

Alexander Borland, of Paisley, in Renfrew, in Scotland, for a machine for measuring water and other liquids, and registering the quantity thereof. Sealed 23rd February, 1839; tour months to specify.

Sir James Caleb Anderson, of Buttevant Castle, Cork, baronet, for certain improvements in locomotive engines, which are partly applicable to other purposes. Feb. 26.

Orlando Jones, of Rotherfield-street, Islington, Middlesex, accountant, for improvements in the manufacture of starch, and the converting of the refuse arising in or from such manufacture to divers useful purposes. Feb. 27.

Frederick le Mesurier, of New-street, Saint Peter's Port, Guernsey, gent., for a certain improvement or certain improvements in the construction of pumps for raising water or other fluids. Feb. 28. Richard Whytock, of Edinburgh, manufacturer, and George Clink, of the same place, colour-maker, for further improvements in the process and apparatus for the production of regular figures or patterns in carpets, and other fabrics in relation to which a patent was granted to the said Richard

479

Whytock, on the 8th of September, 1832, and generally in the mode of producing party colours on yarns of worsted, cotton, silk, and other fibrous substances. March 6.

Pierre Armand Lecomte de Fontainemoreau, of Charles-street, City-road, Middlesex, for certain new and improved metallic alloys to be used in various cases as substitutes for zinc, cast iron, copper, and other metals, being a communication from a foreigner residing abroad. March 8.

Benjamin Goodfellow, of Hyde, Chester, mechanic, for certain improvements in metallic pis tons. March 8.

John Hawkshaw, of Manchester, Lancaster, C. E., for certain improvements in mechanism or apparatus applicable to railways, and also to carriages to be used thereon. March 8.

John Muir, jun., merchant, Glasgow, for certain improvements in the apparatus connected with the discharging press for conducting, distributing, and applying the discharging liquors and the dyeing liquors. March 11.

Thomas Vaux, of Woodford Bridge, Essex, land surveyor, for improvements in tilling and fertilizing land. March 13.

Alexander Croll, of Greenwich, Kent, chemist, for improvements in the manufacture of gas for the purpose of affording light. March 13.

Moses Poole, of Lincoln's Inn, Middlesex, gent., in consequence of a communication from a foreigner residing abroad, certain improvements in tanning. March 13.

Henry Ross, of Leicester, worsted manufacturer, for improvements in machinery for combing and. drawing wool, and certain description of hair March 13.

James Walton, of Sowerby-bridge, York, cloth dresser and frizer, for certain improvements in machinery for making wire cards. March 13.

Henry Huntley Mohun, of Regent's Park, Middlesex, M.D., for improvements in the composition and manufacture of fuel, and in furnaces for the consumption of such and other kinds of fuel. March 13.

Josias Christopher Gamble, of Saint Helens, Lancaster, manufacturer, for improvements in apparatus for the manufacture of sulphate of soda, muriatic acid, chlorine and chlorides. March 13.

James Russell, of Handsworth, Stafford, gastube manufacturer, assignee of Cornelius Whitehouse, of Wednesbury, for an extension of six years from May 26, 1839, of a patent granted to the said Cornelius Whitehouse for an invention of certain improvements in manufacturing tubes for gas and other purposes. March 15.

Joseph Rayner and Joseph Whitehead Rayner, late of Birmingham, Warwick, but now of the city of Coventry, C. E., and Henry Samuel Rayner, of Ripley, Derby, C. E., for divers new and important improvements in machinery for roving, spinning, and twisting cotton, flax, silk, wool, and other fibrous materials. March 15.

John Leigh, of Manchester, Lancaster, surgeon, for an improved mode of obtaining carbonate of lead, commonly called white lead. March 18.

Samuel Clegg, of Sidmouth-street, Gray's Inn Road, Middlesex, engineer, for a new improvement in valves and in the combination of them with machinery. March 18.

Joseph Bennet, of Tumlee, near Glossop, Derby, cotton spinner, for certain improvements in the machinery for carding, drawing, slubbing, roving, and spinning silk, wool, cotton, worsted, flax and other fibrous substances, which improvements are also applicable to other useful purposes. March 20.

John Robinson, of North Shields, Northumberland, engineer, for an invention of a nipping lever for causing the rotation of wheels, shafts, or cylin ders, under certain circumstances. March 22.