STEAM more dependent upon the persons who manage the fire, and whose dispositions are generally a mixture of ignorance and prejudice, duly tempered with the warmth of the element over which they preside; we also doubt whether the same unequivocal testimony can be adduced in respect to the saving of fuel, for this again is more in the stoker's power. In point of originality, too, Mr. Parkes must undoubtedly yield the palm to Mr. Branton; he is anticipated in every part of his invention by the words of Mr. Watt's patent; and we rather think that Mr. Gregson has also touched upon some of the most important parts of his contrivance. We, however, by no means state this opinion with a view to detract from Mr. Parkes's merit; on the contrary, if he has attained that in which Mr. Watt failed, the nearer his means approach to those unavailingly employed by his eminent predecessor, the more substantial is the service which he has rendered the public, and the more praiseworthy the perseverance by which he has accomplished his object. We believe that Mr. Watt never affected to combine diminution in the consumption of fuel with the destruction of smoke, and that, on the contrary, with additional expense and trouble, there were more coals burned; at least this is the only cause to which we can refer the nonconsumption of smoke, and the non-application of his patent, in the greater number, if not in all, the large engines of his erection which we have had occasion to visit. 551. One subject seems to us to have been overlooked by the majority of smoke-reformers, namely, the construction, and more especially the height, of the furnace chimneys. By conveying black smoke, and other pernicious fumes, into a capacious and very lofty chimney, much of the noxious matters that otherwise escape into the atmosphere are decomposed and precipitated, were much struck or condensed within; we some years ago with the effect of a long flue and lofty chimney attached to the steam engine of the Dartford Powder-mills; scarcely any smoke issued from its funnel, the fuliginous particles being almost entirely deposited in the chambers of the flue. The chimneys of the grand junction engine at Paddington, and of the West Middlemore sex water-works at Hammersmith, are illustrative instances; when these machines are at work the former produces little smoke; the latter inundates the neighbouring gardens with perpetual showers of the solid soot, and is the greatest of all conceivable nuisances; yet the only difference is in the height of, the two chimneys, the boilers being in all respects set and constructed alike. Besides, if a high chimney does void smoke, it is generally wafted away and dissipated, except under particular circumstances of wind and weather. 552. As to the requisite height of a chimney for the diminution of nuisance from smoke we are not ENGINE. prepared to give an opinion; it will depend very 553. Among other probable causes of the 554. Lastly, we come to the most absurd portion of the speculations of theoretical smokeburners, namely, the improvement of the atmosphere of the metropolis. Though some are sceptical upon the subject, we will admit that, if no smoke were made in London for a twelvemonth, or if wood-fuel were substituted for coals, there might be some amelioration of the atmosphere, although our locality and climate of adventitious effluvia; it is, however, folly to always render it turbid and misty, independent ascribe any sensible influence upon the great mass of London smoke to some few steam engine chimneys, while every house is busy in the work of contamination, and every street yielding a proportion of filth far exceeding that of any single furnace, though less observed, because administered by separate vents, and in divided doses. 555. A portable high-pressure engine is a desideratum of considerable importance in the erection of buildings and other temporary works. We propose therefore concluding our present article with an account of one which is exceedingly simple in the arrangement of its parts. Fig. 1 plate IV. is an external elevation, and fig. 2 a section of the apparatus. The same letters of reference are employed in both. The cylindrical boiler is represented at A, the cylinder and piston entering at the top of one extremity, and the chimney passing from the other. A four-way cock if k serves to limit and regulate the passage of the steam above and beneath the piston. The steam after its escape passes by the pipe a r F into the chimney T. E, E, are the flanches of the chimney, the clearing hole being placed at Y. The steelyard safety-valve is seen at p n v. The piston-rod is kept in its proper situation by the guides H, I, K, L, and the crank attached to the wheel N. fly-whael M is driven by a connecting-rod and INDE X. BLENKINSOP'S improvement for propelling steam carriages, 283. BRANCA'S revolving apparatus, 39. CEMENTS proper for joining the flanches of iron cylin- CHRONOLOGICAL account of the various improvements CONGREVE'S new method of construeting steam en- CORNWALL steam engines, account of work effected by, in one mouth, 463. Table of work performed by six engines, 465. PADDLES, their uses, 327. PATENTS for improvements in the steam engine,- PAUL, Sir John, his mode of generating steam, 402. PORTABLE high-pressure engine, 555. RIDER'S improvements of the steam engine, 365. ROTATORY engine, Masterman's, 157-197. Eve's, 207. Malam's improvements, 393. SAFETY-VALVE, its use, 353, 354. CYLINDER and piston of atmospheric engine, 379, &c. SMOKE in steam engines, invention for consuming, DOUBLE acting engine by Watt, 234. DOUBLE cylinder engine, 428. 545. Brunton's plan, 546. Parkes's method, 549. SOHO steam vessel, account of, 317. SOUTHERN, Mr., experiments on the latent heat of steam, 28. ELASTIC vapor, practical illustrations relative to its STANHOPE, lord, his ingenious apparatus, 130. formation, 33. EVE's rotatory engine, 207. GAUGE COCKS described, 61. GURNEY'S patent apparatus for generating steam, 227. HAGUE'S patent steam engine, 399. HULL, Mr., proposes the employment of a crank and INDICATOR for steam engine, 458. JAMES's improved mode of constructing steam carriages, 45 M. DE MOURA s apparatus, 67. MALAM'S improvements of the steam engine, 393. MAUDSLEY and Field's apparatus for continually changing the water used in the boilers of steam vessels, 407. M'CURDY'S apparatus, 232. NAVIGATION, the application of steam to the purposes of, 110. NEWCOMEN'S engine, 74. Table by Mr. Smeaton for proportioning its parts, 87. Watt's improvement of it, 105. STEAM, its first application to wheel carriages, 273. STEAM ENGINE, its advantages over pneumatic or STEAM-GAUGE, 372. SYNOPSIS of experimental and calculated results on the elasticity of vapor, 33. TABLE of six engines performing best duty, 465. TAYLOR's invention of certain improvements on steam engines, 413. TAYLOR on the accidents incident to steam boilers, 520 VAUGHAN'S steam engine, 455. WATT, Mr., his experiments on the latent heat of WORKING-BEAM, account of the, 374. STEATITE, or soapstone, in mineralogy, a sub-species of rhomboidal mica. Color grayish, or greenish-white. Massive, disseminated, imitative, and in the following suppositious figures: an equiangular six-sided prism; an acute double six-sided pyramid; and a rhomboid. The first two are on rock crystal, the last on calcareous spar. Dull. Fracture coarse splintery. Translucent on the edges. Streak shining. Writes but feebly. Soft. Very sectile. Rather difficultly frangible. Does not adhere to the tongue. Feels very greasy. Specific gravity 2:4 to 2-6. Infusible. Its constituents are, silica 44, magnesia 44, alumina 2, iron 7-3, manganese 1.5, chrome 2. Trace of lime and muriatic acid. It occurs frequently in small contemporaneous veins that traverse serpentine in all directions; at Portsoy and Shetland; in the limestone of Icolmkill; in the serpentine of Cornwall; and in Anglesey. It is used in the manufacture of porcelain, and for taking greasy spots out of silk and woollen stuffs. It is also employed in polishing gypsum, serpentine, and marble. When pounded, and slightly burned, it forms the basis of certain cosmetics. It writes readily on glass. Humboldt assures us that the Otomacks, a savage race on the banks of the Orinoco, live for nearly three months of the year principally on a kind of potters' clay; and many other savages eat great quantities of steatite, which contains absolutely no nourishment. STEATO'MA, n. s. Gr. 5ɛarwμa. A fat wen. If the matter in a wen resembles milk-curds, the tumour is called atheroma; if like honey, meliceris; and if composed of fat, steatoma. Sharp's Surgery. STEATOMA is a kind of encysted tumor, consisting of a matter like suet or lard, soft, without pain, and without discoloring the skin. STEBBING (Dr. Henry), a learned English divine and controversialist. He attacked the bishop of Bangor, Dr. Sykes, and bishop Warburton; and published many tracts and sermons. He died in 1763. STEED, n. s. Sax. rteda. A horse for state Who like our active African instructs Hang o'er their coarsers' heads with eager speed, Young. STEEDMAN (captain John Gabriel), a Scottish navigator, born in 1745. He wrote an interesting Narrative of an Expedition against the revolted Negroes of Surinam, in 2 vols. 4to., with eighty engravings from his own drawings. He himself was much concerned in the military transactions related in it. He died at Tiverton in Devonshire, in 1797. STEEL, n. s., adj., & v. a. Į Saxon real; STEE'LY, adj. Belg. stael; Goth. stal. A kind of iron refined and purified by fire with other ingredients. See below. Made of steel to point or edge with steel; to harden: steely is made of steel; or hard, firm. That she would unarm her noble heart of that steely resistance against the sweet blows of love. . Here smokes his forge, he bares his sinewy arm, And early strokes the sounding anvil warm; Around his shop the steely sparkles flew, As for the steed he shaped the bending shoe. Gay. After relaxing, steel strengthens the solids, and is likewise an anti-acid. Arbuthnot. Let the steeled Turk be deaf to matron's cries, Tickel. See virgins ravished with relentless eyes. Steel is made from the purest and softest iron, by keeping it red-hot, stratified with coal-dust and woodashes, or other substances that abound in the phlogiston, for several hours in a close furnace. Hill's Materia Medica. STEEL, in modern chemistry and metallurgy, has been defined to be iron united with carbon, See IRON. Steel has properties distinct from those of iron, which render it of superior value. From its higher degree of hardness it admits a finer polish and assumes a brighter color. When tempered, it possesses a higher degree of elasticity, and is more sonorous. It is more weakly attracted by the loadstone, it receives more slowly the magnetic power, but it preserves it longer. When exposed to a moist air, it does not contract rust so easily as iron. It is also heavier, increasing in weight, according to Chaptal, 170th part. M. Rinman has given, as the result of several accurate experiments on different kinds of steel, the following specific gravity 7.795, while he makes ductile iron 7-700, and crude iron 7.251. All iron is convertible into steel, by exposing it to a certain degree of heat for a certain time, along with a quantity of charcoal. Chemists differ in opinion concerning the nature and effects of this process. Some say that steel is produced by absorbing a quantity of caloric. Lavoisier seems to have ascribed the qualities of steel to a slight degree of oxidation; others to a combination with plumbago, and others to a union with carbon. In agreeing with those who say the formation of steel is owing to carbon, we do not differ essentially from those who attribute it to plumbago; for the art of chemistry has now found that these substances are very nearly allied. See CHEMISTRY. There are two ways of making steel; by fusion and by cementation. The first is used to convert iron into steel immediately from the ore, or fron crude or cast iron. By the second way, bar iron is exposed to a long continued heat surrounded by charcoal. Each of these ways has advantages peculiar to itself; but the same causes in fact predominate in both, for both kinds of steel are produced by heat and charcoal. The only difference between the two methods is this: in making steel by fusion the charcoal is not so equally defended from the access of air as in the other way. See IRON. The method of converting iron into steel by cementation is a very simple process. It consists solely in exposing it for a certain time to a strong degree of heat, while closely covered with charcoal and defended from the external air. The furnaces employed for converting iron into steel (says a manufacturer of this metal) are of different sizes; some capable of converting only three or four tons weight, while others are capacious enough to contain from seven to eight or ten tons. The outsides of these furnaces rise up in the form of a cone or sugar-loaf, to the height of a very considerable number of feet. In the inside, opposite to each other, are placed two very long chests, made either of stone, or of bricks capable of bearing the strongest fire; which is placed between the two chests. The bars of iron, after the bottom is furnished with a necessary quantity of charcoal dust, are laid in stratum super stratum, with intermediate beds of the charcoal dust, to such a height of the chests as only to admit of a good bed at top; which is then all covered over, to prevent the admission of the common air; which, could it procure an entrance, would greatly injure the operation. The iron being thus situated, the fire is lighted, which is some time before it can be raised to a sufficient degree of heat to produce any considerable effect; after which it is continued for so many days as the operator may judge proper; only now and then drawing out what they call a proof-bar. This is done by openings fit for the purpose at the ends of the chest, which are easily, and with expedi tion stopped up again, without occasioning any injury to the contents left behind. When the operator apprehends the conversion is sufficiently completed, the fire is suffered to go out, and the furnace, with its contents, is left gradually to cool. This may take up several days; after which the furnace is discharged, by taking out the bars of steel and the remainder of the charcoal dust. There is a manufactory established in the parish of Cramond, about five miles from Edinburgh, in which this method is practised with great success. Great quantities of steel are made there which is said to be of as excellent a quality as any that can be procured from other countries. When the charcoal is taken out, it is found as black as before it was introduced into the furnace, unless by accident the external air has got admittance. The bars preserve their exterior form only; the surface frequently exhibits a great number of tumors or blisters, whence they are called blistered steel. The hardness of steel is much increased by tempering. This conSists in heating it to a red heat, and then plunging it suddenly into cold water. If it be allowed to cool slowly it still preserves its ductility; or, if it be heated again after being tempered, it loses its hardness, and again becomes ductile. In heating steel for tempering it, the most remarkable circumstance is the different colors it assumes, according to the degree of heat it has received. As it is gradually heated, it becomes white, then yellow, orange, purple, violet, and at last of a deep blue color. According to Reaumur, the steel which is most heated in tempering is generally the hardest. Hence it is believed that the more violent the heat to which steel is exposed, and the more suddenly it is plunged into cold water, the harder the steel will be. Rinman, again, has deduced a conclusion directly opposite, that the steel which is naturally hardest demands the least degree of heat to temper it. Different methods have been proposed to determine what degree of heat is most proper; but the easiest method is to take a bar of steel, so long that while one end is exposed to a violent heat the other may be kept cold. By examining the intermediate portions, it may be found what degree of heat has produced the greatest hardness. By tempering, steel is said to increase both in bulk and in weight. Reaumur says that a small bar six inches long, six lines broad, and half an inch thick, was increased at least a line in length after being tempered to a reddish white color; that is, supposing the dilatation proportional in all dimensions increasing at the rate of 48 to 49. Iron also expands when heated; but, when the heat passes off, it returns to its former dimensions. That the weight of steel is also augmented by tempering has been found by experiment. Rinman having weighed exactly in an hydrostatic balance two kinds of fine steel made by cementation, and not tempered, found their density to be to that of water as 7.991 to 1; after being tempered the density of the one was 7.553, and that of the other 7.708. de Morveau took three bars just of a size to enter a certain calibre twenty-eight lines long, and each side two lines broad; one of the bars was M. soft iron, and the two others were taken from the same piece of fine steel. In order to communicate an equal degree of heat to each, in an earthen vessel in the midst of a wind furnace, the bar of soft iron and one of the bars of steel were thrown into cold water; the other bar of steel was cooled slowly over some pieces of charcoal at a distance from the furnace. The bar of iron, and the one of steel that was allowed to cool slowly, passed easily into the calibre again; but the bar of tempered steel was lengthened almost one-ninth of a line. Tempering changes the grain, or at least the appearance of the texture of a piece of steel when broken. This is the mark, which is usually observed in judging of the quality of steel, or of the tempering which suits it best. The tempered bar is broken in several places after having received different degrees of heat in several places. What proves completely the effect of heat upon the grain, at least in some kinds of steel, is that a bar of steel exposed to all the intermediate degrees of heat, from the smallest sensible heat to a red heat, is found to increase in fineness of grain from the slightly heated to the strongly heated end. The celebrated Rinman has made many experiments on the qualities of steel exposed to different degrees of heat in tempering, but particularly to three kinds, viz. steel heated to an obscure red, to a bright red, and to a red white. Hard brittle steel, made by cementation, and heated to an obscure red, and tempered, exhibited a fine grain, somewhat shining, and was of a yellow white color. When tempered at a bright red heat, the grain was coarser and more shining; when tempered at a red white heat, the grain was also coarse and shining. To determine how far steel might be improved in its grain by tempering it in different ways, M. de Morveau took a bar of blistered steel, and broke it into four parts nearly of the same weight. They were all heated to a red heat in the same furnace, and withdrawn from the fire at the same instant. One of the pieces was left at the side of the furnace to cool in the air, the second was plunged into cold water, the third into oil, and the fourth into mercury. The piece of steel that was cooled in the air resisted the hammer a long time before it was broken; it was necessary to notch it with the file, and even then it was broken with difficulty. It showed in its fracture a grain sensibly more fine and more shining than it was before. The second piece, which had been plunged into water, broke easily: its grain was rather finer than the first, and almost of the same white color. The third piece, which was tempered in oil, appeared very hard when tried by the fire; it was scarcely possible to break it. Its grain was as fine, but not quite so bright, as that which was tempered in water. The fourth piece, which was dipped into mercury, was evidently superior to all the rest in the fineness and color of the grain. It broke into many fragments with the first stroke of the hammer, the fractures being generally transverse. M. de Morveau repeated these experiments with finer steel, and with similar results. From these experiments, it appears that steel may be hardened by tempering it with any liquid which is capable of accelerating its cooling. Steel may be unmade, or reduced to the state of iron, by a management similar to that by which it is made, that is, by cementation. But the cement used for this purpose must be composed of substances entirely free from inflammable matter, and rather capable of absorbing it, as calcareous earth or quicklime. By a cementation with calcareous earth, continued during eight or ten hours, steel is reduced to the state of iron. After it has been tempered, it may be again untempered and softened to any degree that we think proper; for which purpose we have only to heat it more or less, and to let it cool slowly. By this method we may soften the hardest tempered steel. For the following important facts respecting the manufacture of steel Dr. Ure was indebted to the proprietor of the Monkland manufactory, where bar and cast steel of superior quality are made. The chests or troughs in which the iron bars are stratified are nine feet long, and composed of an open-grained siliceous freestone, unalterable by the fire. The Dannemora or Oregrounds iron is alone employed for conversion into steel at Monkland. The increase of weight is from four to twelve ounces per cwt. The average is therefore 1 in 224 parts. The first proportion constitutes mild, and the second very hard steel. Should the process be pushed much farther, the steel would then melt, and in the act of fusion would take a dose of charcoal sufficient to bring it to the state of No. 1, cast iron. The charcoal used in stratifying with the bar iron is bruised so as to pass through a quarter-inch riddle. Whenever the interior of the troughs arrives at 70° Wedgewood, the carbon begins to be absorbed by the iron. There is no further diminution of the weight of the charcoal than what is due to this combination. What remains is employed at another charge. Great differences are found between the different kinds of bar iron imported at the same time; which occasion unexpected differences in the resulting steel. The following letter contains important information, from a gentleman possessing great experience in the manufacture of steel. 'Monkland steel-works, 9th November, 1820. 'Sir, Mr. William Murray has written me, that you wished I should communicate to you the reason why bar iron should run into the state of soft cast iron, by the operation being carried too far in the blister steel furnace, and how it does not make cast steel, as cast steel is said to be formed by the fusion of the blister steel in the crucible with charcoal. "The usual practice of making cast steel is to fuse common steel in a crucible, without any charcoal being mixed. The degree of hardness required in the cast steel is regulated by selecting blister steel of the proper degree of hardness for what is wanted." "This statement is made with the view to correct a common mistake, that to make cast steel it is necessary, and that it is the practice, to mix with the steel to be melted a quantity of charcoal. 'Pursuing this mistake, it naturally leads to others. Dr. Thomson says, when speaking on this subject, that cast steel is more fusible than |