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MECHANICS' MAGAZINE,

CONDUCTED BY

A Committee of Civil Engineers and Practical Mechanics.

"It is by means of words only, that a man becomes excellently wise, or excellently foolish."

No. LXXXII.

Saturday, 16th July, 1825.

Price 3d.

DIXON VALLANCE'S MODE OF APPLYING THE LEVER TO THE WORKING OF MACHINERY.

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ON THE APPLICATION OF THE LEVER TO THE WORKING OF MACHINERY.-By DIXON VALLANCE. *

GENTLEMEN,-In a former communication, I gave you my new plan for impelling boats and barges, &c. I again take the liberty of laying before you my plans for working machinery by means of a lever. The lever is perhaps the most simple and powerful of all the mechanic powers, and probably was the first man employed for his assistance. It has been used from time to time in various ways, but I never saw nor heard of its being employed for working machinery in the form I have here presented it. The length and weight of the lever form its power, and these may be increased according to the power which is required to drive the machine it may be applied to. I have found by experiment, that a man with a lever twenty feet long, with a balance of ten hundred weight on the end of it, is able to drive a machine which would require a two-horse power to drive it. In some cases it is very laborious to work machines by a crank, and the lever may be applied in such cases with great advantage.

I am, GENTLEMEN,

Your most obedient,
DIXON VALLANCE, Mechanic.

Libberton, Lanarkshire, 1825.

Description of the Plate.

Fig. 1 represents the lever applied to the working of two pair of

bellows adapted for founders and smiths, &c. Round the fulcrum of the lever is placed a wheel which works two pinions with cranks on their axis, and this again works the shaft or shafts of the bellows. The pinion must go full round to make equal motions to the shafts which work the bellows. A, A, the pinions and cranks; B, B, the shafts which work the bellows.

Fig. 2 represents my plan of a new milk churn wrought by a lever, the same way as the bellows; the churn is about four feet and a half high, nineteen inches long, and nine inches wide. There is a fillet down the middle of the churn on each side, to keep the churn-staffs from coming in contact with each other as they move up and down alternately. A, A, the pinions and cranks; B, B, the shafts which work the churn-staffs; C, the churn; D, the churn-staff; the dots round the upper part of the churn are small air holes.

Fig. 3 shows the lever applied to drive a wheel with a belt, to give motion to other machinery; the lever is well adapted to the working of turning lathes; when working, the lever may be easily kept in motion by the foot. A, the fulcrum of the lever; B, the shaft which gives motion to the wheel: the lever moves between two springs, which makes its motion more easy.

* We are very sorry that owing to the hurry in which the drawing of this week's engraving was sent to the engraver, it was not corrected. The machines would none of them work as they are represented in the plate; but the principle will be quite clear to every one.

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ACCOUNT OF THE FERRY ACROSS THE TAY AT DUNDEE. BY CAPTAIN BASIL HALL, R. N., F. R. S. L. & E.

[THE improvement of the public ferries throughout the country, particularly the Highlands, we conceive to be a subject of very great importance, and one requiring the attention of the public. In order to show the benefits which are likely to accrue from the use of steam vessels at the more important ferries, we have been induced to give some extracts from an account of the ferry across the Tay, at Dundee, published by that able officer and accomplished gentleman, Captain Hall, in the last No. of the Edinburgh Philosophical Journal.]

IN 1817, the counties of Fife and Forfar appointed a Joint Committee to consider the state of the ferry, and to concert measures for its improvement: and it being apparent, upon a slight examination, that, in spite of all its drawbacks, the ferry produced a revenue adequate, with proper care, to the maintenance of a far better system, the number of boats was reduced from twenty-five to eight; and at the same time rendered efficient by stronger crews, better equipment, and, as far as was possible, by punctuality of sailing at stated periods. The landing-places were also greatly improved.

In 1819, an Act of Parliament was procured for erecting piers, and otherwise improving and regu lating the ferry across the Tay. During the discussions on this bill, the idea of employing steam-boats first suggested itself to the Trustees; and after careful inquiries, they decided upon trying the experiment, with a double or twin steam-vessel, such as they learned had been in use for some years on the American rivers, and also at Hamburgh, and on the Mersey,

near Liverpool.*

It was not, however, till towards the end of the year 1821, that the steam-boat began to ply. Previous to that period, but after the improvements had been made in the sailing-boat establishment, the number of foot passengers was about 70,000 annually, and the receipts £2510. There was still, however, no convenient or certain means of transporting cattle or carriages across, except at certain times of the tide, and in fine weather. Until the twin-boat was established, and indeed even for some little time after she began to ply, no very great increase in the revenue took place. There was still a defect in the arrangements, owing to a circumstance which had not been foreseen in time to have it duly guarded against in the Act of Parliament, and which, in consequence of this inadvertency, cost the Trustees a long course of the most unpleasant altercation, and finally, the loss of a considerable sum of money. It was this: While the only convenient landing-place on the north side was Dundee, on the Fife coast or right bank of the Tay, there happened to be two, Newport and Woodhaven, and the steam-vessel was made to ply from Dundee alternately, to these two landingplaces. A few weeks' experience, however, showed, that the greatest public inconvenience must ever attend this alternate system; for not only was punctuality (which it ought always to be recollected, is essential to the existence of a proper ferry) entirely broken in upon, but, in spite of every notification

*The Twin-boat was the invention of the late celebrated Mr. Miller of Dalswinton, who was also the discoverer of Steam Navigation.

hat could be given, passengers were perpetually mistaking the proper point of call. Sometimes the tide, sometimes the wind, did not serve for Woodhaven, and it often happened, that, when circumstances obliged the boat to steer out of the direct course, the people, who were waiting her arrival, were inevitably misled, and so, by repairing to the wrong place, lost their passage altogether. The complaints of the excessive inconvenience of this plan, by every class of passengers, after a few months' trial, became so loud and general, that the Trustees, in July 1822, directed the boat in future to call at Newport only, on the Fife side. The effect was instantaneous; the public regained confidence, and the revenues of the ferry increased rapidly. The following is the amount of the fares collected for the last five years:

In 1820,.........£2510

1821,..

1822,

1823,

1824,

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2526 13 9 3209 9 0 .3552 4 10 ..3790 12 10

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passage, allowance being made for the set of the tide, may be stated at about two miles and a third. This passage is made, by the twinboat in seventeen minutes, at an average, in neap tides; and in twenty-three at spring tides. In very blowing weather, it sometimes takes from thirty to fifty minutes, and once it took an hour. During 1824, the passage never interrupted for one whole day; and it was only five times detained throughout the whole owing to hard westerly gales during the ebb tide.

was

year,

There are two steam-boats belonging to the ferry, one of which is employed at a time, except in harvest, when the reapers come down, or at the seasons when numerous droves of cattle come from the north. On these occasions, both are put in requisition, though not absolutely necessary, in order to avoid the possibility of delay. In order still farther to meet the public convenience, a pinnace, with four able seamen is stationed at each side of the ferry, for the purpose of affording a passage to travellers who are unwilling to wait for the periodical sailing of the steam-boat. These boats are also in attendance during the night, when the steam-boat has ceased to ply.

As the twin-boat is very little known as yet in this country, an account of one may possibly prove interesting, if not useful to some readers. There are some material differences between the two boats at Dundee, but that last built being the most perfect of the two, a description of her will be the most satisfactory.

She is called the George the Fourth; is 90 feet long over all, and 29 broad; she has 6 feet 8 inches depth of hold; and draws, when light, 4 feet of water-and,

when loaded, rarely more than 5 feet 4 inches. She is of the double kind of steam-boat, with a single paddle-wheel, working in the middle, between two divisions, or separate smaller boats, placed parallel to one another, at the distance of 8 feet apart. Over these two divisions, are placed horizontal beams, covered by a deck, the planks of which, instead of being placed fore and aft, in the usual way, cross the vessel from side to side, and thereby contribute greatly to the strength of the whole. To a person standing on the deck, she appears to be but one vessel. At each end there is a space railed off for cattle, one 33 feet by 27, the other 27 by 21. From 80 to 90 head of cattle is her average load; but, upon one occasion in fine weather, she actually carried 103 cattle, and 3 horses. In the middle part of the deck, between the spaces allotted for cattle and carriages, there is

ample space for foot passengers, for whom also, in rainy weather, there are two commodious cabins. The machinery of the two steam-engines (each of 20 horse power,) is concealed below; but the paddle wheel, being 14 feet in diameter, necessarily rises considerably above the deck, where it is covered by a wooden case. This wheel is 7 feet wide, and is immersed 18 inches in the water. It is a matter of perfect indifference which end of the boat goes foremost, both being alike in all respects. As the method of fixing the rudders, one of which is fixed at each end, is, of course, different from that of a ship, it may be useful to describe it particularly. The rudder is a plate of iron 4 feet long, and 3 feet deep. It is fastened to a vertical spindle, reaching from the middle of the stern to the water. In the first boat employed in the Tay, the rudder was attached by

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one end to the spindle, so that, when she was in motion, its whole length trailed behind. But this rudder being found difficult to move, a device was adopted which answers the purpose perfectly. The spindle, instead of joining the rudder at the end, is fixed to it at onethird of the length; so that, when the vessel is in motion, two thirds are abaft, and one-third before the spindle, resembling a large weathercock, or vane inverted. A horizontal wheel is fixed to the upper extremity of the spindle, and this is turned by a wheel and pinion by the steersman. Both the divisions composing each twin-boat are flat bottomed, have perpendicular sides, and are sharp bowed; the angle at which the two bows meet at the extremities being 60°, ample room. is allowed for the escape of the back-water. The rudder is placed in the middle point between the two stems; and, of course, lies directly in the centre of the current of back-water thrown out by the paddle - wheel. The steersman stands on a raised platform, above the taffrail, from whence he commands a clear view over the paddlecase. There are no masts; and the only resistance which is offered to the wind, is from the chimneys of the engines.

Though the manner in which the two engines of a steam-boat are made to act in concert, be known to every person at all acquainted with the subject, it may perhaps interest some readers to describe, in a popular way, the beautiful device by which this object is accomplished. The paddle-wheel is moved by one continuous shaft, to which both engines give their impulse, by means of two cranks, or bends in it, formed so as to be at right angles to each other. Thus, when one of the cranks is either quite up, or quite down, and con

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