Under these circumstances, a brief account of this curious machine may be interesting.

The turbine is neither more nor less than an improvement on the spiral wheel of the East, and the horizontal wheels so often met with in the south of France, Spain, Portugal, and Italy. Plates, and descriptions of these wheels, may be seen in the works of Zonca, Bockler, Ramelli, Walter, and Belidor; with this difference, however, that the water acts principally by its impulse.

Monsieur Naviere, in his notes on "Belidor's Architecture Hydraulique," gives the theory of the horizontal wheels which are employed at Toulouse and in the Pyrénées. In these examples the water acts by percussion only, and the result of the experiments of Messrs. Tardy and Piobert give about 0.34 of the power expended for the useful effect, while according to M. Poncelet's experiments in 1825, only of the power expended was rendered useful. M. Poncelet, whose researches in hydraulic science have been so valuable, gave, in 1826, a theory for the curves of an horizontal wheel, on the principle of reaction, namely, that the water should enter the wheel at the circumference and leave it at the interior, without velocity. In 1835, M. Burdin (engineer of mines), proposed to construct another kind of wheel, which he designated turbine, but in 1823, previously in the year, M. Fourneyron had directed his attention to this machine, which, with unwearied perseverance, he succeeded in perfecting in the year 1833.

The machine of M. Burdin receives the water at the top of a cylinder, or vertical drum, and rejects it at the lower end. The water then flows either nearer or further from the circumference, according to the forms of the curves on the surface of the cylinder, the height of which should be regulated to half the height of the entire fall; whereas in the turbines of Fourney. ron, the thickness of the cylinder is only a few inches. The water issues out of the curves horizontally from the interior of the cylinder, and penetrates in every direction the counter curves of the exterior-wheel, and escapes horizontally through vertical openings in the exterior-wheel; or, to simplify the explanation, we have only to imagine a wheel with curved buckets laid horizontally, and the column of water issuing from the centre to the circumference, or by reversing the system, cause the water to issue from the circumference towards the centre. So far the principle. But the main difficulty lies in the construction, and this M. Fourneyron has acquir. ed by long experience.

Two turbines, constructed by M. Fourneyron, were experimented upon by M. Morin (so well known for his valuable experiments on friction, &c., &c.), one at Moussay, in the Vosges, and the other at Müllback, in the department of the Lower Rhine. The former has a fall of three metres, or 9.84 feet, and the latter a fall of seven or eight metres, or from 23 to 26 feet. The effects were measured by the friction lever of M. Prony, which was applied to the vertical axles of the turbines, and although the velocity of the turbine varied from 140 to 180 revolutions per minute, the difference between the actual expenditure, disposable effect of the fall, exceeded it only by. It results from the experiments of M. Morin, first, that the wheel of Moussay of two feet nine inches diameter, and four and one-third inches in thickness, on a fall of twenty-four feet six inches, is equal to 45 horses, and, secondly, that from 180 to 290 turns per minute the useful ef fect is 69 per cent., and which is very little diminished when the wheel is drowned.

The results of M. Morin's experiments on the turbine of Müllback, were: 1st. That the wheel of the turbine having a diameter of 6 feet, and a thickness of one foot, and a fall of from 11 to 12 feet, transmits a useful effect of 91 horses.

2d. That at the velocity of from 50 to 60 turns per minute, with the sluice well opened, the useful effect is 78 per cent. of the power expended.

3d. That the velocity of the wheel may be varied very greatly without altering the effect more than from to of the maximum effect.

4th. That when the wheel is drowned it makes little difference from the effect when not drowned.

5th. That although the expenditure of the water may vary in quantity in the ratio of from three to five, the useful effect is sensibly the same.

M. Morin has made experiments upon other turbines which have led to similar results. But the results obtained at the spinning factory of M. d'Eichtal, at St. Blaise, in the Black Forest, are curious.

There, the wheel of the turbine is only 21 inches in diameter, the fall 354 feet in height, the number of turns 2,300, and the power 40 (60?)

horses.

When at Paris in October, 1838, I was recommended by Messrs. Arago and Morin, to visit the turbine recently erected at St. Maure; circumstances prevented me from having the advantages of M. Morin's company, nevertheless the machine was very politely shown and explained to me. The following is a brief description:

Diameter of the wheel of the turbine, 5 feet 8 inches.

Breadth of ditto, 10 inches.

Number of turns per minutes, 55.

Height of fall, 11 feet.

Estimated power, 40 horses.

The axle as well as the other machinery, which was polished, had a crown wheel fixed near the bearing of the upper part, sufficiently large in diameter to drive 10 pinions, connected with as many millstones, each 40 inches in diameter, and they were then erecting three similar mills on the same floor, so that there were concentrated 40 pairs of millstones, driven by four turbines, equal in power to 40 horses each, or 160 horses altogether.

The machines were constructed by an English mechanic, established in Paris. I was, however, informed that no one possessed the art of laying out the curves but M. Fourneyron,* and that the attempt to construct one of these machines without the superintendence of the inventor would be attended with disappointment.

Messrs. Wedding and Carliczect, of Berlin,t have investigated the curves with attention, and find them to be cycloidal. See the annexed plate.

* We should like to save M. Fourneyron the trouble of guarding this secret any longer.-ED. R. M., &c.

f Versiech mit horizontalen wosserradern, von Wedding et Carliczect.-Berlin, 1837.

Description of the Engraving.

L, Lever. W, Water level. F, Friction wheel. D, Dynamometer.

a, Main axle of the machine.

bb, Pipe which incloses it.

cc, Disk of the turbine fixed on the main axle.

ee, Curves or disks let into the platform PP.

dd, Curves on disks fixed round the circumference of the turbine, on which the water issuing out of the curves of platform PP, impinges.

ff, Bolts and screws for raising or lowering the circular sluice gg. Operation. To set the machine in motion the sluice gg is drawn up by means of the screws and bolts ff.

The water, which is continually resting on the platform PP, with the pres sure of the whole fall,immediately issues out between the curve disks, and, impinging on the exterior curves of the turbine, causes it and the main axle, with all its machinery, to revolve rapidly.

In the annexed engraving, a friction wheel and friction break are attached to a lever, the vibration of which, and consequent power of the machine, are ascertained by the dynamometer.

The advantages of these machines are their simplicity and economy; they occupy very little room and can be placed in situations where a common vertical water wheel could not. The facility with which their velocities can be increased or diminished renders them well calculated for spinning, or for any mechanical operation which requires uniformity in changes of velocity ad libitum, and whereby increase or diminution of velocity may be obtained without the intervention of a train of wheels and their consequent friction and loss of power. To use the words of the commission appointed to examine the report of M. Morin, "The turbine is, of all the hydraulic machines in use, the most effective that has yet been compressed in the smallest form."* GEORGE REnnie.

New Source of Light.

M. Seguin has communicated to the Académie des Sciences, at Paris, a memoir on the distillation of animal substances, in which he states, that he has reduced the process to such a degree of simplicity,'as to render it profitable for the sake of the products of the distillation. Thus, from the carcase of a horse he obtained, by destructive distillation, 700 cubic feet of gas, suitable for purposes of illumination, 24 lb. of sal ammoniac, and 33 lb. of animal black. The gas obtained was found to be composed of one part of olefiant gas and four of carburetted hydrogen, and might be preserved for months, in contact with water, without being in any way injured, or its brilliancy, as a combustible, impaired. M. Seguin found that 3,234 cubic inches of this gas, when burnt for one hour, gave twice and a half as much light as a Carcel lamp.

Atheænum.

The Clinometer.

Sir, This instrument takes its name from two Greek words, signifying a

* Expériences sur les Roues Hydrauliques a arbre vertical appelée turbine, par Arthur Morin, Capitaine d'Artillerie, &c. &c., Metz.

bed, or strata, and a measure; it is therefore intended for the purpose of ascertaining the depth of soft mineral, or earthy, strata.

Explanation.-A, a cross piece for working the instrument; B, a strong pole graduated to feet, &c. for fixing to T a stout iron tube with an opening equivalent to one-third the circumference as shown at P. P, an inner tube to work freely upon the interior of T, of similar shape. K, K, projections for opening and shutting the instrument; S, a suitable screw for working the instrument into the ground.

A simple and efficient instrument for this purpose has long been a desider. atum. If a landed proprietor or surveyor is desirous of ascertaining the nature of the subsoil of an estate, or an engineer the subsoil of the bed of a river (as in the case of the Thames Tunnel,) with the means generally em

ployed for such purposes, it becomes an operation of considerable time, trouble and expense. The landed proprietor or surveyor, goes to work by taking with him one or two men with pick, shovel, &c., who commence operations (perhaps in the centre of a fine meadow) by digging an unsightly pit some three or four feet square, and so reach the required depths. The engineer on the other hand, will, supposing him to go about the job sans cérémonie, in the method at present employed, bring with him augers, borers, &c., and by abstracting the earth by little and little, arrive at the required information. But with my instrument, the surveyor will soon accomplish his task. Throwing it over his shoulder as he would his gun, off he goes, and having fixed upon a spot, takes the cross piece, passes it through the hole at the top of the instrument, introduces the same into the ground, and works it down screw-fashion, from left to right, (the inner tube remaining shut.) After working it to the required depth, as indicated upon the stalk of the instrument, the motion is reversed, when the resistance of the projections upon the inner tube to the surrounding earth will cause the instrument to open and to charge itself with the soil at such depth. The motion being again reversed, will cause the tube to close; when the instru ment, being withdrawn, will be found to contain, pure unmixed soil, taken from the required depth, that is, the soil through which the tube was passing, when the motion of the instrument was reversed.