3 travellers, 5 inches diameter and 47.24 inches long, making turns per minute, and one combing cylinder 15 inches diamet and 47.24 inches long, making 6 revolutions per minute, requi together 1.939 horse-power, and produce 17 lbs. of carded fl per hour.

One finishing carding cylinder, 40 inches diameter and 47 inches long, making 176 revolutions per minute; 5 distributi rollers, 4 inches diameter, making 23 revolutions per minut 4 travellers, 5 inches diameter, making 7.3 revolutions per mi ute; 1 combing cylinder, 15 inches diameter, making 3-4 revol tions per minute, together require 811 horse-power, and produ 81 lbs. of carded flax per hour.

One spinning-machine, containing 132 spindles, making 2,7 revolutions per minute, spinning yarns from No. 7 to No. 9, quires 1-24 horse-power, and produces 34 lbs. of yarn per ho

One spinning-machine, having 168 spindles, making 2,7 revolutions per minute, and producing 3 lbs. of No. 18 to yarn per hour, requires 1.96 horse-power.

Wet spinning of flax: one drawing-frame drawing a sliv for No. 20 yarn, requires 493 horse; drawing-frame drawi sliver for No. 50 yarn, requires 487 horse; drawing-frame dra ing sliver for No. 70 yarn, requires 495 horse.

Second drawing-frame, drawing two slivers for yarns N 20 and 30, requires 68 horse; second drawing-frame, drawi two slivers for yarns Nos. 30 and 40, requires 544 horse; seco drawing-frame, drawing one sliver for No. 60 yarn and one No. 70, requires 617 horse.

Third drawing-frame, drawing two slivers for yarns Nos. tc 60, requires ⚫69 horse.

Roving-frame of 8 spindles, preparing the flax for yarn N

20, requires 608 horse; roving-frame of 8 spindles, preparing the flax for No. 30 yarn, requires 486 horse; frame of 16 spindles, preparing the flax for No. 40 yarn, requires ⚫987 horsepower.

Paper Manufacture.-In some cases the pulp, or stuff of which paper is made, is obtained by beating the rags by stampers; but more generally it is produced by placing the rags between revolving cylinders stuck full of knives. When produced by stampers, the proportions of the apparatus are as follows: weight of stampers, 220 lbs.; distance of the centre of gravity from the axis of rotation, 4 feet; rise of the centre of gravity each stroke, 31⁄2 inches; number of stampers, 16; number of lifts of each stamper per minute, 55; weight of rags pounded in 12 hours by each stamper, 33 lbs.; weight of stuff produced in 12 hours by each stamper, 122 lbs. ; power consumed, 2.7 horses.

Chopping-cylinders, for preparing the pulp: number of cylinders working, 2; number of turns of cylinders per minute, 220; weight of rags chopped and purified in 12 hours, 528 lbs. ; power consumed, 4.48 horses.

In another instance, 10 cylinders for preparing the pulp, making 200 revolutions per minute, 1 paper-making machine, cutting-machines, pump, and accessories, consumed 50-horse power. The machine made 13 yards of paper per minute, and the produce was 1 ton of printing paper per day of 24 hours.

In another instance, 28 pulping-cylinders, and 3 paper-making machines produced 2 to 3 tons of paper per day of 24 hours, and consumed 113 horse-power.

Printing Machinery.—Printing large numbers is now performed by cylindrical stereotype plates, revolving continuously; and the 'Times' and other newspapers of large circulation are thus printed. The impressions are taken from the types in papier maché, and in twenty minutes a large stereotype plate is ready to be worked from. The power required to drive this machine varies with the number of impressions required in the hour. For 5,000 impressions per hour, the power required is 3.75 horses; for 6,000 impressions, 4·77 horses; 7,000 impressions, 59 horses; 8,000 impressions, 7-03 horses; 9,000 impres

as to be ready at once to put into the post-office or to distri by hand. The most expeditious mode of stereotyping w be to use steel types set on a cylinder, against which and cylinder of type-metal is pressed, and the paper would the printed in the same manner as calico.

Glass Works.-Mill to grind red lead: to grind 3 tons vertical arbor requires to make for the first ton 20 revolu per minute, for the second 25, and for the third 40, consu 5.28 horse-power. Vertical millstones, to grind clay and br crucibles; diameter of the granite stones or runners, 3·7 thickness, 14 foot; weight, 1 ton; distance of edge ru from central spindle, 4 feet; number of turns of the arbo minute, 7; power consumed 1.92 horse. In the 12 hours 8 charges of about 300 lbs. each of old glass pots are gro and about 3 tons of dry clay. Wheels for cutting the glass, athes for preparing the cutting wheels, 5; lathes for meta power consumed, 17.9 horses; wheels driven by each h power, 9.5.

Iron- Works.-The weekly yield of each smelting furna Wales is from 100 to 120 tons; pressure of blast, 2 to 3 lbs square inch; temperature of the blast, 600° Fahr.; yield we of each refining-furnace, 80 to 100 tons; of each puddling-fur 18 tons; of each balling-furnace for bars, 30 tons; of each ing-furnace for rails, 80 tons; iron rolled weekly by puddle 300 tons; by rail rolls, 600 tons; power required to work train of rail rolls, 250 horses; to work puddle rolls and sque 80 horses; small bar train, 60 horses; pumping air into blast-furnace, 60 horses; into each refining-furnace, 26 ho rail saw, 12 horses.

Weaving by compressed air.-In common power-looms

shuttle is driven backward and forward by a lever which imitates the action of the arm in the hand-loom. But it has long been obvious to myself and others that it might be shot backward and forward like a ball out of a gun, by means of compressed air. This innovation has now been practically carried out. But the benefits derivable from the practice have been much exaggerated, and a much more comprehensive improvement than this is now required. Indeed, reciprocating looms of all kinds are faulty, as they make much noise, consume much power, do little work, and cannot be driven very fast; and the proper remedy lies in the adoption of a circular loom in which the cloth will be woven in a pipe, and in which many threads of weft will be fed in at the same time.

Circular Loom.-The obvious difficulty in a circular loom, is to drive the shuttle round continuously within the walls formed by the warp. One mode of driving proposed by me, is by magnets or other suitable form of electro-motive machine, which does not require contact; and the shuttle should be a circular ring, with many cops placed in it, so that many threads might be woven in at once. The desideratum, however, is to weave a vertical pipe with the bobbins of the weft in the centre of the circle; and this may be done by depositing the thread between metallic points, like circular heckles, which points will change their positions inward or outward at each time a thread is deposited. These points would conduct the threads of the warp.

CHAPTER VIL

STEAM NAVIGATION.

STEAM navigation embraces two main topics of enquiry:the first, what the configuration of a vessel shall be to pass through the water at any desired speed with the least resistance; and the second, what shall be the construction of machinery that shall generate and utilise the propelling power with the greatest efficiency. The second topic has, in most of its details, been already discussed in the preceding pages; and it will now be proper to offer some remarks on the remaining portion of the subject.

The resistance of vessels passing through the water is made up of two parts:-the one, which is called the bow and stern resistance, being caused partly by the hydrostatic pressure forcing back the vessel, arising from the difference of level between the bow and stern, and partly by the power consumed in blunt bows in giving a direct impulse to the water; while the other part of the resistance, and the most important part, is that due to the friction of the water on the sides and bottom of the ship. The bow and stern resistance may be reduced to any desired extent by making the ends sharper. But the friction of the bottom cannot be got rid of, or be materially reduced, by any means yet discovered.

When a vessel is propelled through water, the water at the bow has to be moved aside to enable the vessel to pass; and the velocity with which the water is moved sideways will depend upon the angle of the bow and the speed of the vessel.

When