should be slow, say 25 to 30 turns per minute, according to the substance operated on and the diam eter of the work.

30. It is sometimes required to have a projection on a portion of a surface which in other respects is to be cylindrical, e. g. a feather on the side of an arbor, to enable it to carry round some thing which may be fitted on it. In such cases, if the feather or projection is to be short in proportion to the whole length of the work, the circumference of the work at the place of the projection may be brought to an uniform surface with the rest of the work, by the revolving cutter described in § 20. To do this, the apparatus should be furnished with a plain cutter, and made to cut to the proper depth, at the root of one side of the projection; when it has done this, the lathe mandril should be turned slowly round by hand (the cutter at the same time continuing to revolve rapidly), and by this means the extra matter on the surface of the work will be gradually cleared away, until the opposite side of the projection which is to be left has been brought round to touch the cutter. The apparatus should then be shifted a little to the right or left, and the operation repeated until the work be complete.

§ 31. If the projection extend considerably in the direction of the axis of the work, this method would be tedious, owing to the great number of shifts of position required to be given to the cutting apparatus. Another method is therefore had recourse to, which leads us to describe a very important implement in machine making. It is called the planing engine, and has been but recently introduced into some of the best workshops in this country. This implement may be said to be the greatest gift made by ingenuity to the useful arts, since the invention of the common turning lathe, as it holds the same place in relation to the formation of straight lines and plain surfaces, which the turning lathe does to lines and surfaces of revolution.

§ 32. We shall proceed to give a description of this important machine. Plate DXXVI, Fig. 1, is an isometrical perspective view of a planing engine of medium size. A is a strong bed of cast iron, the general form of which may be varied according to circumstances, but it must have two angular ridges B dressed truly parallel, and in the same plane relatively to one another. On these ridges lies a table C, having two grooves corresponding to the ridges B, and its upper surface planed flat and parallel to these ridges. To this table a go-and-come motion is given by a winch D and an endless chain. The table is pierced all over with holes to admit the passage of screw-bolts, by which any piece of work to be operated on may be securely fastened down to it.

From the bed A rises a frame E, of which the face ridges e are truly perpendicular to the ridges B; each pillar of this frame has a groove, as at f, through which pass bolts by which the cross slide frame F is fixed in any required position, parallel to, or at an angle with the plane of the table C.

On F is fitted the tool or cutter carriage G, which has a variety of slides and adjustments which we shall not attempt to detail;-its motion across the plane of the table is regulated by the long leading screw seen at FF,-the depth of the cut of the tool is regulated by a slide in the carriage G, which is also furnished with a leading screw and divided head H. This last mentioned slide has an adjustment by which it may be set perpendicular to, or at an angle with the cross slide F.

§ 33. Let us now suppose a piece of metal of any form, bolted down firmly on the table,* let the cross slide be adjusted parallel to the surface of the table, at such a height above it that the point of the cutter may be made to act on the work; if then the table be moved in the proper direction by means of the winch, it is evident that a groove of the form of the point of the cutter will be made in the upper surface of the piece of metal, and that this groove will be parallel to the plane of the table's motion; if the carriage G be now shifted to either hand by the leading screw F, a second groove will be cut parallel to the first, or if the shift be less than the breadth of the point of the tool, the first groove will have been widened as much as the cutter has been shifted, and by repeating the shift of the screw F, and the motion of C, the groove will gradually become a plane surface parallel both to C and the cross slide F. If the slide F had been adjusted at an angle to the plane of C, instead of being parallel to it, then the plane produced on the work would, in one direction, have been parallel to the table, and in the other to the cross slide.

§ 34. When the angle of obliquity with the plane of the table is not great, the work is easily accomplished by setting the cross slide to the angle required, but when the plane to be cut is perpendicular to that of the table, or is nearly so, the effect must be produced by adjustment of the slides of the carriage G.

35. It is hoped that the action of this engine will now be sufficiently understood to allow of our reverting to what we said in § 31, regarding the most convenient way of forming cylindric surfaces, having feathers or ridges left on some part of their circumference: in order to effect this and some other purposes, the following provision is made in the construction of the planing engine. In the middle of the table C is the grooved passage J, by means of which two head-stocks K (like those of a turning lathe) may be fixed at any required distance from one another: in the one head-stock is a dead centre, and in the other a short mandril turning in a collar, and having a divided plate and index on its outer end. The piece of work being fixed between these centres, and its position duly shifted round them by means of the plate and index, it will be easily understood that the alternate movement of the table and of the work round its centres, will gradually produce a cylinder, or will leave some portions of the surface uncut, accordingly, as may be required; these effects may be further modified by the adjustments of the cross slide and of the carriage

G, and by combining their shifts with the movements and shifts of the table C, and of the work in

the head-stocks.

§ 36. It appears surprising to us that the ingenious artists who invented, and who employ this beautiful engine in their works, have not added to it that which appears to us would be an important extension of its powers, viz. the means of drilling holes perpendicular to, or at any required angle to the surfaces produced by its action.

If the slide which carries the cutter be removed from the carriage G, and one substituted, such as shown at Plate DXXVI, Fig. 2, where L is a strong arbor, (similar to, but on a larger scale than that mentioned in § 10,) in which drills may be fitted, and M, a pulley of any required diameter, round which a band may be applied to give it motion, then by means of the leading screw of the cross slide and the movement of the winch D, the drill arbor L may be brought over any required part of the work, and a hole may be pierced, which will necessarily be quite true in its direction, without any care or nicety on the part of the workman. Again, if instead of a boring instrument being put in the arbor L, a chuck something like N were screwed on its nozzle, then by means of eccentric cutters like O, circular grooves and valve seats might be cut out, or cross pivots turned, which would be truly at right angles to others which might previously have existed on the work, and which might have been fixed in the centres of the head-stocks KK. Such an apparatus would be eminently useful in making the working gear of steam engines.

37. Various other instruments besides the drill ing frame may in the same way be applied, by means of slides, to the carriage G. Ingenious workmen will easily devise such as may be suited to their particular lines of pursuit. We shall, however, venture to suggest one, which, although we have never seen it applied to metals, we think may be so with advantage in many cases of nice fittings, we mean the mortise chisel. If a steel cutter like a mortise chisel were fitted to a slide in the carriage G, and were to be worked up and down by a lever handle of adequate length, while the carriage G itself was gradually shifted by the leading screw F, some operations might be easily and accurately executed, which present considerable difficulties in other methods. It will at once be seen what advantages such processes would afford in the construction of machines, the due performance of which depends much on the accurate adjustment and true bearing of the parts, and we may safely venture to say that by means of the planing engine a gigantic zenith sector or a transit instrument could now be made with greater accuracy by a common workman in a Manchester millwright's shop, than could fifty years ago have been made by the best London instrument

maker.

The planing engine which is represented in the plate may be said to be of a medium size. It has been executed by Messrs. Paterson and Mitchell of

Edinburgh, for their own use. Some engines are made much smaller, and are applicable to such work as would otherwise be filed in the vice; others again have been executed by Sharp, Roberts, & Co., Messrs. Lilly and Fairbairn, and other engineers in Manchester, on such a scale, that very large pieces of work are planed in them, e. g. billiard tables in one casting of 12 feet by 6, which are executed in this way with perfect accuracy.

In Plate DXXVII, Figs. 1, 2, 3, 4, and 7, are drawn to the scale at the foot of the engraving. Figs. 5 and 6 are to a scale of double size.

Fig. 1 shows a slide-rest lathe, calculated to turn light metal work to about 10 inches diameter. The frame KK which rises from the table, is intended solely for working the apparatus shown at Figs. 5 and 6, and described in paragraphs 10 to 22 passim. The drum H is put in motion by a band S from the great wheel below the bed. Its height above the bed should be sufficient to keep it entirely clear of the head of the workman.* The frame II swings on the turned rod J, which screws into the uprights KK; there is another turned rod L, on which a loose pulley M slides; on the lower rod of the frame II are two similar loose pulleys M'M', and there is a fourth one N on the rod J. When the drilling apparatus at Fig. 5 is put into the socket E of the slide rest, it is set in motion by a band, as shown at PP': as this band must be long enough to allow of the pulley P' being moved to a certain distance from the drum H, it becomes sometimes necessary when P' is near it, to have the means of keeping the band tight; this is done by a small flying pulley at the end of a cord which passes over the loose pulley N, and has a weight at the end of it similar to that at O. The flying pulley is made to bear on the band PP' to keep it in a due state of tension.

When the apparatus at Fig. 6 is used, the band is applied as shown at QQ' passing over the loose pulleys M'M'. Tension is given to the band by means of the weight O, which, by a cord passing over M and hooked to the lower end of the swinging frame II keeps it equally stretched, although Qmay vary its position and distance.

Figs. 2, 3, and 4 are details of the slide rest; the letters of reference are the same as in Fig. 1st.

Fig. 7, is a section of part of the lathe mandril and its pulley, AAA the grooves for the band, B'B show a groove or channel wider at bottom than at top, in which the heads of two screwed studs can travel round: these studs may be made fast in any required situation by pinching the screws; one stud and screw is shown separately at B". If they, for example, were made fast in their places at 90°, or a quarter of a circle apart, and if the pointer R, Fig. 1st, were inclined inwards, until its pin touched the outer edge of the groove, and were then made fast, it is plain that the mandril, instead of turning freely round, could turn through a quarter of a circle only, as the studs would, by striking on the pin of the pointer R, prevent it from going farther in either direction; by this means any required portion of a circumference may be operated on

without risk of going too far or making unequal arcs in different parts of the work. The studs are introduced into the channel through the opening C from the concavity of the pulley.

Fig. 8, is a convenient form of a throw chuck, in which the pin A can be made to project more or less, and be fixed near to, or far from the centre, by one pinching screw nut D; the pin A fits neatly in the sliding piece B, the front part of which is sawn through, and the back part screwed. A washer C is interposed between the nut D and the back of the chuck. When the nut D is turned to the right, it draws B between the dove-tailed sides of the slide E, by which A is jammed, and becomes immovable, until relieved by slackening the nut D. The above designs have been taken principally from lathes made by Drane of Birmingham, whose accuracy and ingenuity are conspicuous in every thing which proceeds from his manufactory.

In the 46th volume of the Transactions of the London Society of Arts, designs and minute detailed descriptions are given of an excellent lathe for machine-makers' purposes, by Clements of London. We venture to recommend it as a good study for artists.

The best makers of turning apparatus we happen to know are as under.

For very large work-Messrs. Lilley and Fairbairn, and Messrs. Sharp, Roberts, & Co. of Manchester.

For medium and light work-Mr. Drane of Birmingham, and Messrs. Paterson and Mitchell of Edinburgh.

For such turning lathes and apparatus as are required by amateurs-Holtzapfel and Deyerline of Charing-Cross are unrivalled for the high finish and elegance of their work. We have also seen amateur's lathes made by Drane of Birmingham, which, in point of accuracy and efficiency, could not be exceeded.

It may be expected that we should give some idea of the cost of such apparatus as we have described, but this is very difficult, as there is so much variety in the nature of the accompaniments required by different individuals. We shall however quote the prices of such as are sometimes used by the best machine makers.

A 16 inch slide lathe capable of turning cylindrical objects, 13 feet long and 13 inches diameter, or flat objects 24 inches diameter, with traversing and reversing apparatus for the main slide; cross slide for flat surfaces, and driving apparatus for five different degrees of speed-costs about £275. A 12 inch lathe, with compound slide rest, eccentric lock rest and driving apparatus £105. A planing machine, capable of planing objects ten feet long, three feet wide, and three feet high, and surfaces at any internal or external angle, with driving apparatus complete-£285.

The additions to this machine, suggested in paragraph thirty-five and thirty-six would add but little to its cost, and would greatly extend its powers.

The machines here specified are formed entirely of metal, and are finished and adjusted with the most scrupulous accuracy.

TUS

Below the union of its two main branches, the Tuscaloosa, now a navigable stream, continues the course of Locust river S.W. 40 miles, to about 10 miles below the town of Tuscaloosa, Here the stream inflects to S.S. W. 40 miles to its junction with Tombigbee at Demopolis, and between Greene and Marengo counties.

The valley of Tuscaloosa is a triangle of 150 miles base from the mouth to the sources of Locust river, perpendicular 70 miles, and area 5250 square miles, draining the counties of Walker, Blount, Jefferson, and part of Lafayette, Tuscaloosa, Greene, Marengo, and Perry; and lying between N. Lat. 32° 30', and 34° 23', and Lon. 9° 18′ and 11° W. from W.C. See Art. Tombigbee, p. 42, of this volume.

TUSCALOOSA, county of Alabama, bounded W. by Pickens, N.W. by Lafayette, N.E. by Jeffer son, E. and S.E. by Bibb, S. by Perry, and S. W. by Greene. Greatest length from east to west, 54 miles, and the area being about 1400 square miles, the mean breadth must be 26 nearly. It extends in

Lat. from 32° 52' to 33° 28' N., and in Lon. from 10° 10' to 11° 02′ W. from W.C.

The declivity of this very large and important county is to the southwestward, and in that direction the Tuscaloosa traverses it by a very circuitous channel, dividing it into two not very unequal sections. The northwestern part is also traversed by Sipsey river, flowing also to the southwestward. The southeastern border on Bibb, follows the dividing ridge between tributary fountains of Tuscaloosa and Sipsey rivers. The surface is rolling rather than abruptly hilly. Much of the soil excellent. Excluding the Creek territory east of Coosa river, Tuscaloosa county is not far from central, regarding the extremes either of north or south or of east and west.

Though a wilderness at the termination of the last war with Great Britain, this new county contained, in 1820, a population of 8229.

By the post-office list of 1831, Tuscaloosa, beside the capital of the same name, had offices at Buck's store, Carthage, and Halbert's.

Tuscaloosa, the seat of justice, and of the government of the state of Alabama, is situated on the left bank of Tuscaloosa river, and very near the centre of the county. According to a table published in the post-office list, 1831, this state capital is, by the nearest mail route, 994 miles from Philadelphia, and 560 from Charleston in South Carolina. By a calculation on Mercator's principles, it bears S. 564° W. from W.C.; distance 720 statute miles; the given post distance between those places is 858 miles. N. Lat. of Tuscaloosa 33° 12', Lon. 10° 43′ W. from W.C. DARBY.

The physical appearance of Tuscany is equally interesting and diversified. The Appenines traverse it in a south-east direction, but the highest summits of that range in Tuscany do not exceed 3,000 feet. Several smaller chains extend from this celebrated ridge in different directions, declining in elevation as they approach the sea. The champaign parts of the country consist chiefly of valleys extending along the banks of the numerous rivers with which the dutchy abounds. The rivers indeed, or rather streams, are so many, that they have been estimated at 200, all of which have their rise in the Appenines, or the mountains that diverge from them, and flow into the Mediterranean. The most important are the Arno, the Ombrone, and the Chiana. The valley of the Arno, it may here be mentioned, has been much celebrated. At a remote period, when Florence and Pisa were distinguished commercial cities, it was embellished with the villas of wealthy merchants. It is now inhabited by workmen, and in it are manufactured the linen stuffs that form an important article in the commerce of the grand dutchy, as well as those straw hats which, under the name of Leghorn hats, are known in every part of the world.

The climate of Tuscany may be regarded as on the whole agreeable and favourable, and characterized by that mildness, serenity and salubrity for which Italy has always been remarkable. But this description must not be taken in an unqualified sense. The sirocco or south-east wind, so prevalent in the south of Italy, rages to a most baleful extent in Tuscany, blasting the hopes and destroying the labours of the vine-dresser and the agriculturist. The district, known by the name of the Maremma, is probably the most unhealthful spot in Europe, and is as remarkable for its pestilential humidity as other parts of the same dutchy are for their fertility or beautifully diversified scenery. It stretches along the sea coast, from Pisa southward, and in superficial extent is equal to about 1,700 English square miles. It consists nearly of one continued marsh; it is comparatively destitute of inhabitants, the population being only forty persons to a square mile; and though means have already been used, and others are still contemplated, for draining and cultivating this unproductive district, it still remains as barren and as noxious as ever. The Maremma is chiefly devoted to pasturage. Notwithstanding the general fertility of Tuscany,

state.

agriculture has not been brought to a very improved There is indeed no instance of a large farm, the country being subdivided into such small patches, that in some cases a pair of oxen is sufficient to perform the ploughing necessary in six or eight such lots. The most fertile portions of the dutchy are devoted to the cultivation of vines and olive trees; and almost all the corn fields also, are intersected by rows of these and other fruit trees. The peasantry are so poor, that even in the case of such patches, the landlord is obliged to supply part or the whole of the farming implements; a wretched system of farming, to which the name metayrie (the coloni partiarii of the Latins) has been applied. The Tuscans, however, display great ingenuity in irrigating their lands, and in extending cultivation along the declivities of their hills and mountains.

Some towns in Tuscany, particularly Florence and Pisa, were at one time remarkable for commercial enterprise. But circumstances are now changed. Leghorn is now the only port of any consequence. Its exports consist of wine, oil of olives, fruit of various kinds, perfumed essences, linen, woollens, Leghorn straw, manufactured silks of various sorts, marble: its imports are confined chiefly to articles from the north of Europe, and from the Levant, including tropical commodities.

The government is monarchical, not restrained by any representative body or any written authority, but exercised with mildness and judgment. The title of the sovereign is that of Arch-Duke; his appellation is Imperial Highness. The public revenue is £708,500; the public debt £5,000,000; the army does not exceed 4,000 men. The established religion is the Roman Catholic; the number of Jews amounts to 20,000.

Tuscany has been long celebrated for the learned men it has produced: in which respect it is probably superior to any other portion of Europe of equal population. It can boast of a long and illustrious list of statuaries, architects, painters, poets, authors historical, literary, scientific, theological. It can boast of the best collections of the fine arts, and the finest specimens of architecture in Europe. The celebrated picture gallery of the De Medicis is well known. Tuscany possesses three universities, those of Florence, Pisa, and Sienna. The number of public libraries is seven, one of them at Florence containing 130,000 volumes, including 11,000 MSS. Elementary schools are in a flourishing state; the Lancastrian mode of tuition has been introduced.

The history of Tuscany can be told in a few words. It long resisted the inroads of the Romans; and it was not conquered by that people till the year of the city 474, or less than three centuries before the christian era. After the fall of the Roman power, it was tributary to Lombardy. During the contention in the middle ages, Florence, Pisa, and Sienna erected themselves into separate commonwealths. The sovereign power of Florence, and afterwards that of the whole of Tuscany, came into the hands of the Medicis, an illustrious family that first acquired immense wealth by trade, and which, remarkable for literature and taste themselves, knew

how to appreciate and reward these distinctions in others. This enlightened family, to whose patronage of the arts and of learning not only Tuscany but Europe are indebted, became extinct in 1737, when by arrangement between France and Austria, the archdutchy was conferred on the duke of Lorraine. Bonaparte deprived this latter family of their territory, which was erected into a monarchy under the name of the kingdom of Etruria, and given to the duke of Parma; it was afterwards declared an integral part of the French empire. But on the downfall of this ambitious conqueror, it was restored to the family who had succeeded the Medicis, and the island of Elba was added to it. (See ELBA.) Ferdinand, a very enlightened prince, was in 1824 succeeded by his son Leopold II., now grand duke of Tuscany.

See the various Travels in Italy, particularly Simond's Travels in Italy and Sicily; Addison's Remarks on Italy; Eustace's Classical Tour, and Roscoe's Life of Lorenzo de Medicis.

TUSCARAWAS, river of the state of Ohio, the main and eastern constituent of Muskingum river, has its remote sources in Medina and Portage counties, interlocking sources with those of Cuyahoga and Mahoning branch of Big Beaver river. The different higher branches uniting in the northwestern angle of Stark county, and by a course a little E. of S. passes the villages of Clinton, Massillon, and Bethlehem, in Stark, and Bolivar, Zoar, Canal-Dover, New Philadelphia, Schoenbrun, Gnadenhutten, and Newcomerstown, in Tuscarawas county, bends gradually in the southwestern part of the latter, to a course nearly due west, which it pursues to its junction with White Womans creek at Coshocton, in Coshocton county, to form the Muskingum river.

The entire comparative course of Tuscarawas is less than 80 miles, and only about 70 below the New Portage, where it is united to the Cuyahoga by the Ohio Canal. This important public work gives great interest to the physical history of Tuscarawas. The canal follows its valley either near or at no great distance from its banks, from the village of New Portage, in Medina county, to its mouth at Coshocton. The canal at the summit is 873 feet above the level of the Atlantic ocean, 305 feet above lake Erie, and 499 feet above the Ohio at Portsmouth.

TUSCARAWAS, county of Ohio, bounded south by Guernsey, southwest by Coshocton, northwest by Holmes, north by Stark, and east and southeast by Harrison. The extreme length, either north and south or east and west, is nearly equal to 30 miles; the mean breadth 24, and area 720 square miles; extending in latitude from 40° 13′ to 40° 39', and in longitude from 4° 8' to 4° 44' west from W.C.

The general declivity is to the southward, in which direction the northern part is traversed by Tuscarawas river and "Ohio Canal." In the southern section of the county, both the natural and artificial channels wind to S.W. and W.

By the post list of 1831, there were post offices