The advantage of turning the propeller by the direct action of the engines, was generally acknowledged. The method of driving it was nearly the only problem remaining for solution, and that difficulty being once overcome, screw-propellers must necessarily, from their vast advantage over paddle-wheels, in every respect but that, be universally adopted.

Mr. Hawkins said that about the year 1825, Mr. Jacob Perkins adapted to the stern of a canal boat, a propeller of about 25 feet in circumference, which might be described as resembling two sets of wind-mill vanes, the solid axle of one set revolving within the hollow axle of the other, the two axles being turned in contrary directions, and the dip of the blades being about half their radius. The propulsive force was stated to have been very effective; the experiments, which were put an end to by the breaking of part of the engine, were never renewed, in consequence of disputes among the patentees; but he considered that propeller as the best that had hitherto come under his notiee, and he had endeavoured to draw attention to it by read

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ing an account of it, at the Meeting of the British Association at Cork, in 1843.

Mr. Grantham stated, that in order to test the comparative effect of the expanding pitch, Mr. Woodcroft had adapted to the stern of a vessel, two screws of equal area, one being of a regular, and the other of an expanding pitch; they were connected by a cross shaft, and were worked by manual power, and it was found that the vessel always yielded to the impulse of the expanding pitch propeller, and was turned by it from the direct course.

With respect to the advantage of a large amount of surface, he had found that the action of the propeller of the Liverpool Screw, which had been enlarged three times, was decidedly improved by the alterations; the speed of the engines always remaining the same.

Mr. Galloway said, that the surface of the propeller of the Liverpool Screw might probably have been too small at first, and therefore each increase would naturally improve its effective power. The area of the propeller should be in proportion to the body to be moved; this law was common to screwpropellers and to paddle-wheels.

The instrument represented in the preceding engravings, furnishes a remarkable instance, at once of the difficulty with which even the most useful inventions find their way into use, and of the utility of the Agricultural Shows which have come recently into fashion in promoting the adoption of improvements in farming implements. The first year it was brought out (1841), two only were sold, and a third given away; in the second year the inventor had no better success, and to tempt farmers to give the machine a fair trial he was induced to lend out several on merely nominal terms of remuneration. At length, at the Doncaster exhibition last year of the Yorkshire Agricultural Society, the machine had the good fortune to obtain the largest prize awarded by the Society; and since then the demand for it has been so great throughout the northern parts of England, that the patentee is now manufacturing it at the rate of two a day. With the view of making its merits still better known, and thereby accelerating its introduction into other parts of the kingdom, we lay the present description of it before our readers.

Fig. 1 is an elevation, and fig. 2 a plan of the machine. A A is a strong framing, and b b shafts; c is an axis on which is placed a series of rollers d d, from the outer circumference of each of which project a number of teeth e e and ff. Each roller turns freely on the axis independent of the others, and while the

teeth e e project radially from the rollers, the others, ff, project at right angles to them; two peculiarities which distinguish this crusher from all others, and by which not only the earth is penetrated and broken up with more facility, but the teeth are rendered, as it were, self-cleaning.

The purposes for which this roller has been found most applicable are stated to be these:

1. For rolling wheats as soon as sown, especially when sown on strong lands late in the year, in which case once rolling and crushing is found equal to once hoeing.

2. For rolling corn upon light lands as soon as sown, and in the spring, after frost. It is found to answer much better than the pressers upon light soils, to which it gives a suitable degree of firmness and tenacity, without leaving a smooth surface.

3. For rolling corn three or four inches out of the ground, upon land infested with the wire-worm and grub.

4. For rolling strong fallow lands. It breaks up the hardest clods, and pulverizes them into a fine mould, making sure of a sowing season in the driest weather. By once or twice rolling, the machine will pulverize the largest clods, and give a fineness of surface far surpassing what is produced by the spike roller, or any other implement.

5. For rolling grass lands, meadow lands infested with worms, and mossy

lands. A plain roller is afterwards used.

6. For rolling between rows of potatoes, &c. It is worked between three or four rows at once, by taking off the required number of roller-parts, and placing iron bushes in the spaces required, so that the roller-parts do not injure the plants.

It will, of course, be understood in every case, that the machine can only be used when the land is so dry as not to stick to the teeth.

LIGHTHOUSE FOR THE ISLAND OF
BERMUDA,

The cast-iron lighthouse for the Jamaica lighthouse commissioners, which was constructed at Messrs. Bramah and Robinson's manufactory three years ago, and erected on the east end of Jamaica a few months afterwards, on the specification and under the immediate superintendence of Alexander Gordon, Esq., C.E., has given so much satisfaction,* that the Lords of Her Majesty's Treasury were induced to contract with Mr. Gordon for the construction of a similar lighthouse, but on a still larger scale, for the top of Gibb's Hill, on the main island of Bermuda, where numerous engineering difficulties have hitherto prevented the erection of a lighthouse in masonry. The work has been several weeks in progress, and may now be seen rising above the houses near the Waterloo-bridge-road. The constructors of the iron work are Messrs. Cottam for the tower, and of the lantern, Messrs. Wilkins and Son, of Long Acre.

The tower is conical, and the diameter at the base 25 feet, tapering to 15 feet at the narrowest part near the top, when it is sponsoned out for the gallery on which

* Extracts from the Report of the Lighthouse Commissioners to the House of Assembly, Jamaica, De· cember 15, 1842.-" Mr. Gordon lost no time in meeting the wishes of the Commissioners, and in a few weeks submitted to them the plans of several towers, with reports and explanations as to the probable expense, and a recommendation of the one he considered best suited to meet the object contemplated. *** On the 8th March, 1841, the iron tower recommended by Mr. Gordon was selected, and finally determined on, and instructions given to proceed with the work. These instructions were promptly attended to by Mr. Gordon with a zeal and alacrity which enabled that highly talented gentleman to inform the Commissoners, only eight months after, that the tower was about to be shipped for its place of destination. • • • On the evening of the 1st May, 1842, the light was exhibited, and has since continued to be in full operation."

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the lantern is to be placed. The total height, from the base to the top of the lightning rod, will be 138 feet, and when erected on Gibb's Hill, Bermuda, will be 368 feet above the level of the sea. The lantern is to be fitted with a lenticulated apparatus of the first order, on Fresnel's plan, and the light (a fixed one with bright flashes) will be visible all round the dangerous reef of rocks to the northward and westward of this valuable military and naval station in the Atlantic Ocean.

The outside carcase of the tower is composed of 139 cast-iron plates. There are seven rooms, lighted by portholes and ports, fitted with plate glass. The rooms are lined with wrought iron, panelled in oak frames, and the ascent from the bottom to the top is by means of a spiral staircase of iron with oak treads. The floors are all of cast-iron, and there is in the centre a hollow column, 16 inches in diameter, for waste water-pipes, and for the ascent and descent of whatever may be required in the lightroom and lantern, or for any of the seven rooms, thus obviating the necessity of carrying anything up or down the stair

case.

The whole is constructed with a special view to the resistance of those terrific hurricanes and thunder storms so common in Bermuda, and some of the West India islands. Being a perfect conductor of electricity, no lightning can affect it; being also incombustible, it cannot be destroyed by fire. Altogether, in short, it gives the fairest promise of being another lasting monument of the engineering talent of the mother country.

Mr. Gordon's lighthouse at Jamaica we described at the time of its temporary erection in this country, three years ago. It has several times been struck by lightning, but without sustaining the least injury.

THE FACTORY QUESTION.

Suppose the expense of building and fitting up a cotton factory with the necessary machinery, &c. to amount to 180,000l., and that the proprietor will require, to keep it in full operation, a floating capital of 20,000l. He engages 800 hands, whose average annual wages may be rated at 30. each; the other miscellaneous expenses may be taken at

5,000l. per annum. Now, suppose we allow the proprietor, in the name of interest for expenses of building, tear and wear of machinery, insurance, &c., 7 per cent. on the sunk capital, and 34 per cent on the floating capital, and that the proprietor's annual gain is 10,000l.; it is then required to determine what his annual gain will be when the daily hours of labour are reduced from 12 to 10, the wages remaining the same? And what also will be his annual gain when the wages are reduced in the ratio of the hours of working?

That is, the annual value of the work produced by all the hands amounts to 52,300. Now when the hours are reduced from 12 to 10, the annual sum produced will be less than the above sum, or, 43,5831. Hence, by the reduction of the working hours from 12 to 10, the wages remaining the same, the proprietor's annual gain will be diminished by (52,300-43,5831) 8,71617. and his net income will be (10,000-8716) only 1,28311.

But should the wages be reduced in proportion to the time, the proprietor will save th of 24,000l., or 4,000l. which will raise his annual profit to

(1,283 +4,000) 5,283}. Or, suppose a stoppage of 3 months in 12 were to take place, the daily time of working being still twelve hours, and that the proprietor were to allow the hands half pay when unemployed, then-—

Corollary.-52,300 ÷ 800 - 30 = 35,375, is the proprietor's amount of gain on each hand, and 10,000 ÷ 35,375 =283; hence 800-283 = 517; that is, if the proprietor were to reduce the number of hands from 800 to 517, his annual gain would be 0.

GEORGE SCOTT. 41, Seymour-place, Bryanston-square, April 26, 1844.

A FEW FACTS RELATIVE TO THE RISE AND PROGRESS OF THE COTTON MANUFACTURE OF THIS COUNTRY.

Sir, I beg leave to forward to you the accompanying "Facts," which, as the descendant of Mr. John Kay, of Bury, I have considered it my duty to lay before the public. As they are not generally known to the mechanics of Great Britain, I hope they may not prove uninteresting, and am, Sir, Your obedient servant, THOS. SUTCLIFFE.

Royal Hotel, Liverpool,
April 16, 1844.

Facts, &c.

Mr. Guest, in his interesting work on the Cotton Manufactures, in alluding to that ingenious mechanic, who, in 1764 and 1772, invented the spinning jenny, waterframe, and a machine for carding, has justly said, that "nothing is more singular, or shows in a stronger point of view the great evanescence of individuals, and the knowledge of circumstances affecting them in Manchester, arising principally from its great increase in new settlers, and population, and the great fluctuation of its inhabitants, that a man of such celebrity, and so well known to the last generation of Manchester merchants and manufacturers, as Mr. Thomas Highs (of Leigh, in the county of Lancaster), should be now almost forgotten." Yet thirty-four years previous to Mr. High's invention being improved by Messrs. Hargreaves, Arkwright, and Crompton, the reputed "first fathers," and the factory system established; "the long-closed door to the era of invention" had been opened by Mr. John Kay, of Bury, in 1738, by his improving the loom, and accelerating the speed of the shuttle.*

At the period of Mr. Kay's invention, nearly all the woollen and linen goods, were manufactured in the country by small farmers, or others who rented cottages. They received the material in a raw state, which

* Vide Aikin's History of Bury.