Hydrogen

Azote.

1.42

56.68

5th. Gas taken under the tymp plate, or aperture by which the

slags escape a little below the twyre.

These were formed of

Carbonic oxide..

Hydrogen...

Azote......

51.35

1.25

47.40

We see that the oxygen of the carbonic oxyde notably exceeds the atmospheric oxygen due to the azote, and that produced by the decomposition of water due to 1.25 of hydrogene. This result is to be again returned to but already the absence of all carbonic acid may be remarked in the ascending current, taken at a short distance from the twyre.

6th. Gas taken at the twyres opening.

These gases present nothing but atmospheric air, of which a few per cents have been converted into carbonic acid. After this it is hard not to admit that the oxygen of the atmosphere, carried directly upon the charcoal, produces carbonic acid, but it is important to observe, from the analysis of the gas taken from the tymp, that the carbonic acid is rapidly changed into carbonic oxide, under the influence of excess of carbon, and of the high temperature in the neighbourhood of the twyre, a temperature such that, a gun barrel exposed to it is calcined and melted in about one or two minutes, and a porcelain tube melts when not broken by the first access of heat.

Second Series of Experiments.—Examination of the Gases from the Blast Furnace at Audincourt.

This as mentioned is fed with charcoal and raw wood, which represents in heating power the one-third of its volume of charcoal. The author ascertained first, as to the depth in this furnace at which the wood was converted into charcoal; that wood which remained one hour and three-quarters, at three metres depth from the mouth (in the belly, whose height was eight metres) preserved its own appearance, and the ore mixed with it had not lost its moisture, whilst at one metre lower, i. e. at four metres from the mouth, an exposure of three and a quarter hours reduced the wood to perfect charcoal, and the ore to magnetic oxide.

The analysis of the gases of this furnace accords perfectly with the preceding, save that in the upper half of the belly of the Audincourt furnace, the gases contain nearly twice as much vapour of water, in consequence merely of the use of raw wood, which gets dried in this part of the furnace; lastly, that the gases contain

acetic acid, and oxicarburets or carburets of hydrogen, condensible by sulphuric acid; but it was remarkable that the hydrogen which escaped the condensation of the acid, was free from all carbon; it resembled, then, as to its chemical condition, the gas from a furnace fed exclusively with charcoal. The circumstances of this furnace, rendered the obtaining the gases from the immediate neighbourhood of the twyre, more convenient than in the preceeding case; the author, therefore, was enabled here to observe, in a certain manner, the formation of carbonic acid by the action of the air, preceeding the formation of carbonic oxide; and has convinced himself of the following important fact,-i. e. that the oxygen of the air, blown in at a little above the twyre, is found in the carbonicacid and carbonic oxide produced, so that he may be certain there is no considerable quantity of iron burnt, in this part of the furnace, under the influence of heat and air.

Finally, M. Ebelmen has found that in a cupola of 1.67 metres, in height, worked with coke, the gases taken at 0.1, metre, in depth, from the mouth, consisted of

from which it results, that the column of coke is insufficient to convert all the carbonic-acid into carbonic oxide, and that there is besides, a quantity of oxygen carried up over the iron, which scorifies it, a result very different from the preceding cases.*

The next part of M. Ebelmen's memoir, relates to the theory of blast furnaces.

To follow easily the modifications of composition, which the ascending gaseous column suffers in the blast furnace, we must take a definite quantity of azote for a term of comparison-say 100 volumes, which are equivalent to 26 volumes of atmospheric oxygen, but as the azote enters by the twyre, represented by 100 volumes, and is still represented by this same number at its escape by the mouth, it is easy in referring to it the composition of each section of the ascending column, to follow the changes which arise in the relative proportion of the constituent gases.

The analyses of M. Ebelmen, demonstrate that the composition of the gaseous column at a determinate height is constant, when

The importance of much deeper cupolas than are generally used in our foundries in Britain, is thus forcibly shewn; by deepening them 1 or 11⁄2 diameters more, we should save loss of iron in oxidation, save fuel in burning the carbonic acid brought to the state of carbonic oxide, and melt the iron faster.-R. M.

No. CIV.-VOL. XVIII.

R

ever the blast and the experiment of taking out the gases are constant. However, the analysis of the gases cannot give the mean composition of the gaseous section, which is to be found in the hearth, at a few decimetres from the twyres; and here is the place to state the explanation given by M. Ebelmen, of the great proportion of carbonic oxide indicated by analysis in the gases taken from this part of the furnace. According to him the substances which cover the mass of fluid metal in the bottom of the hearth, and which adhere to the sides of the same, contain silicate of iron, in a pasty state, and charcoal; hence there is an incessant reduction of oxide of iron, which gives rise to carbonic oxide, which is drawn out, through the tube of aspiration, along with the other gaseous contents of the column.

Following, then, the transformations of the stratum (couche) of air, entering by the twyres, and passing off at the mouth; its oxygen, converted, first, into carbonic acid, is then changed into carbonic oxyde by means of,-i. e., by uniting with, a quantity of charcoal, equal to that of the carbonic acid,—the volume of oxygen is thus doubled. This conversion takes place in a space very close to where the original one, namely, the production of the acid, is produced. At the same time the vapour of water, introduced with the atmospheric air, is reduced to carbonic oxide and pure hydrogen.

If no silicate of iron were produced, if there were not added to the ore that passes through the furnace, slags of difficult reduction, the section arrived at the height of the boshes, would be represented by 100 of azote, 5.25 carbonic oxide, plus as much more of the latter as would be produced by the oxygen of the hygrometric water of the air, plus the hydrogen of this same water.

From the base of the belly to the mouth, the carbonic acid again appears and augments, until we come to the middle of the belly, when the proportion becomes constant, at the same time the amount of carbonic oxide diminishes, because it produces carbonic acid at its own expense; and in the upper region of the lower half of the belly, there takes place no other chemical phenomena than this re-conversion, which producing an augmentation of the oxygen separated from the oxide of iron of the ore, of 12.7 to 17.

The hydrogen augments from the boshes, to within 1.33 meters of the mouth. It is to be understood, that it is in the lower half of the belly, that the water, the carbonic acid, and in a word all the volatile matters of the ore, of the flux, and of the combustibles are disengaged. In taking account, then, of all the matters re-acting in a blast-furnace, M. Ebelmen comes to the following conclusions.

(To be continued.)

123

NOTICE OF EXPIRED PATENTS.

(Continued from page 61.)

JOSEPH CLISILD DANIELL, of Lumphey, Stoke, Wiltshire, Clothier, for improvements applicable to the manufacturing and preparing of woollen cloth.-Sealed August 5, 1828.

JOHN LANE HIGGINS, of Oxford Street, London, Gentleman, for improvements on wheel carriages.-Sealed August 11, 1828.—(For copy of specification, see Repertory, Vol. 9, third series, p. 328.)

WILLIAM MENECKE, of Park Place, Peckham, Surrey, Gentleman, for improvements in preparing materials for and in the making or manufacturing bricks.-August 11, 1828.-(For account of specification, see Repertory, Vol. 9, third series, p. 22.)

LEWIS ROPER Fitzmaurice, of Jamaica Place, Commercial Road, Master in the Royal Navy, for improvements on ship and other pumps, which improvements are also applicable by certain alterations to turning lathes and other purposes. -Sealed August 11, 1828. -(For account of specification, see Repertory, Vol. 8, third series, p. 666.)

WILLIAM GRISENTHWAITE, of Nottingham, Esquire, for a new process of making sulphate of magnesia, commonly called Epsom salts.-Sealed August 11, 1828.-(For account of specification, see Repertory, Vol. 8, third series, p. 534.)

HENRY MAXWELL, of No. 99, Pall Mall, London, Spur Maker, for an improvement in spring spur sockets.-Sealed August 13, 1828.

THOMAS STIRLING, of the Commercial Road, Lambeth, Surrey, for improvements on filtering apparatus.-Sealed August 16, 1828. -(For account of specification, see Repertory, Vol. 9, third series, p. 143.)

BENJAMIN MATTHEW PAYNE, of the Strand, London, Scale Maker, for improvements on weighing machines.-Sealed August 18, 1828. EDWARD BARNARD, of Nailsworth, Gloucestershire, Clothier, for improvements in weaving and preparing cloth.-Sealed August 19, 1828.

PHILIP FOXWELL, Clothier, WILLIAM CLARK, Cloth Dresser, and BENJAMIN CLARK, Cloth Dresser, all of Dye House Mill, in the parish of Minchinhampton, Gloucestershire, for improvements on machinery for shearing, cropping, or cutting, and finishing woollen and other cloths, and cassameres.-Sealed August 19, 1828.

WILLIAM SHARP, of Manchester, Spinner, for improvements in machines for spinning or roving of cloth, silk, wool, or other fibrous substances.-Sealed August 19, 1828.

GEORGE STRATTON, of Frederick Place, Hampstead Road, in the county of Middlesex, Gentleman, for an improvement in warming and ventilating churches, hot-houses, and all other buildings; which improvements may be applied to other purposes.-Sealed August 28, 1828.-(For copy of specification, see Repertory, vol. 8, third series, p. 454.)

PATENTS GRANTED FOR SCOTLAND, From May 25, to June 23, 1842.

JOSEPH CLISILD DANIELL, of Tiverton Mills, near Bath, for improvements in making and preparing food for cattle.-Sealed May 25, 1842.

ROBERT LOGAN, of Blackheath, in the county of Kent, Esquire, for improvements in obtaining and preparing the fibres and other products of the cocoa-nut and its husk.— Sealed May 28, 1842.

THOMAS HENRY RUSSELL, of Wednesbury, in the county of Stafford, Iron Tube Mannfacturer, and CORNELIUS WHITEHOUSE, of the same place, for improvements in the manufacture of welded iron tubing.-Sealed May 28, 1842.

THOMAS MIDDLETON, of Loman Street, in the borough of Southwark, and county of Surrey, Engineer, for an improved method of preparing vegetable gelatine, or size for paper, and also an improved mode of applying the same in the manufacture of paper. Communicated by a foreigner residing abroad.-Sealed June 6, 1842.

JOHN RAILTON, of Blackburn, in the county palatine of Lancaster, Machine Maker, for certain improvements in machinery or apparatus for weaving.-Sealed June 6, 1842.

THOMAS HEDLEY, of the town and borough of Newcastle-upon-Tyne, Gentleman, and CUTHBERT RODHAM, of Gateshead, in the county of Durham, Millwright, for