A second turbine, at the same establishment, is worked by a column of water of 108 metres, or 354 feet high, which is brought into the machine by cast-iron pipes of 18 inches diameter of the local measure, or about 16 inches English. The diameter of the water-wheel is 144, or about 13 inches English, and it is said to expend a cubic foot of water per second; probably the expenditure may be somewhat more than this.

The width of the water-wheel across the pier is 225 or less than a quarter of an inch. It makes from 2200 to 2300 revolutions per minute; and on the end of the spindle, or upright shaft, of the turbine, is a bevilled pinion, of nineteen teeth, working into two wheels, on the right and left, each of which has 300 teeth. These give motion to the ma chinery of the factory, and drive 8000 water spindles, roving frames, carding engines, cleansers, and other accessories. The useful effect is reported to be from 80 to 85 per cent. of the theoretical water power. The water is filtered at the reservoir before it enters the conduit pipes; and it is important to notice this, since the apertures of discharge in the wheel are so small as to be easily obstructed or

choked.

The water enters the buckets in the direction of the tangent to the last element of the guide-curves, which is a tangent to the first element of the curved buckets. The water ought to press steadily against the curved buckets, entering them without shock or impulse, and quitting them without velocity, in order to obtain the greatest useful effect; otherwise a portion of the water's power must be wasted or expended, without producing useful effect on the wheel. The engravings show a section of this turbine, and a quadrant of its water-wheel, drawn to a scale of one half of the actual size.

It is difficult to imagine that a machine so small as this can give motion to the works of a cotton mill, on so large a scale. Professor Ruhlmann says, that when he saw it actually doing so, he could not, for some time, credit the evidence of his senses; and, although he went purposely to examine it, his astonishment prevented him from compre hending, in the first instance, that the fact was really as it appeared.

There are many places, especially in hilly districts, where high falls of water are found, and where the nature of the ground affords facilities for making reservoirs, so as to

ensure a constant supply, where the height of the column of water may compensate for the smallness of its volume. In such situations it may be conveyed in pipes to the highpressure turbine, which may often be applied with advantage for grinding corn, working threshing machines, or for crushing ore, and other purposes. There are other situations in which a great volume of water rolls, with but little fall, and it has been shown that, with a head of only nine inches, the low-pressure turbine has done good service.

The illustrations here given, as explanatory of the progress and construction of the turbine, are an elevation and plan of Dr. Barker's mill; an elevation and plan of Mr. Whitelaw's mill; and diagrams, showing the method of striking the spiral curves to form the arms; with a section, showing how the mill is connected with the supply-pipe; the loose collar is pressed upwards against the revolving part of the machine by three bow springs, fixed between the flanches; the collar is prevented from revolving, by a steady pin; and the parts in contact are ground together to be water-tight.

A sectional elevation of a low-pressure turbine, with one of the three screws for raising and lowering the circular sluice (with plan). The screws are connected, and act together, by means of toothed wheels. (See fig. 22.)

Also a plan of the water-wheel, the guide curves, and a portion of the circular sluice. The curved buckets, which are made of thin plate-iron, are screwed against loose blocks or pieces of cast-iron; and these are secured, by means of screw-bolts, within the rim of the water-wheel.

The turbine of St. Blasier, shown in section. The body of the machine is of cast-iron; the wheel is of hammered iron; and the spindle, or axis, of steel. (See Fig. 23.) The letters refer to the same parts on plan. (See Fig. 24.) The foot of the spindle, and the pivot and step on which it revolves, are tempered to extreme hardness. The oil-pipe at the foot of the pivot is connected with a small force-pump, or syringe, which, at regular intervals, injects a little oil into the step for lubrication. The pump is worked by a slow motion from the machinery.

In all cases it is necessary that the foot of the spindle shall be made hollow, and run upon a fixed pivot. The spindle must never run in a hollow step. The pivot should be quite cylindrical, and it should truly fit the spindle, with as little play as possible; the top of the pivot should be but

very slightly convex. The water and mud must be carefully excluded, and the parts regularly oiled.

A quadrant or fourth part of the wheel, with the guide curves, and the sluice or regulator of the turbine of St. Blasier. This engraving is one-half of the natural or full size of the machine itself; the bent arrow shows the direction in which the wheel revolves.

There is also another difference in the construction of turbines which should be noticed. Some have been made which receive the water at their circumference and discharge at their centre. Several of these have been erected in the United States, and have worked very well; but the amount of duty done by a given quantity of water is not so great as when it is admitted at the centre and escapes at the circumference, where it can do so more freely. It is therefore unnecessary to go very minutely into the details of this machine, which is like Mr. Appold's centrifugal pump, so