WATT'S COUNTERPOISE-CRANE. 警官 We present our readers with an engraving and description of another of those masterly contrivances of Mr. Watt, by the help of which the building of the Bell Rock Lighthouse was so much facilitated (see vol. 11, p. 401). The Counterpoise-Crane was invented by Mr. Watt, when the height to which the lighthouse was built rendered the use of gy-ropes to steady the jib-crane no longer convenient, and when the opening in the centre of the building admitted of the crane's having a permanent situation. The patterns of this crane were wholly made under the direction of Mr. Watt, and he went to the Calder Iron-works to superintend the casting; and though, after it had been put together at Arbroath, it was sent to Edinburgh to get some slight alterations (we believe in the barrels c and d), yet we have reason to think that the hint of these alterations was given by Mr. Watt previous to its removal. This crane, though of great weight as well as power, stood "perfectly steady upon its own cross foot, at the same time that it would raise with facility a weight of two tons, and could command any point within a. ring beginning three feet from its centre, and extending nine feet in breadth, or even more, if necessary. At the same time it was so contrived that the workmen, while standing on the platform attached to the crane itself, could raise and lower themselves and it at pleasure. From the three sets of wheel and pinion, and of winches, aa, ee, ii, it will be seen at once that the crane has three powers; but the manner of its action will be better understood after we have noticed the several parts. Fig. 1 is a side-view, and fig. 2 a horizontal plan. AB is the upright centre upon which the crane turns: it is formed of a cast-iron cylinder, ten inches in diameter. It is supported by the cross foot at A, the arms of which extend about three feet from the centre, and it has a series of holes for receiving the wedge, 2 (fig. 1), upon which the weight of the crane is supported. The pulley at B merely slips into the opening of the cylinder, and it can be removed at pleasure, so as to allow an additional cylinder to be added. The sides of the crane are formed of two very strong frames of cast iron, which are held together by bolts, two of which are made very #strong (one of which is shown at 1,' 9 fig. 2), for receiving the upright. DE is the weight-arm, formed of two cheeks, and strengthened by the wrought-iron stays, kkjogani teom a OGH is the counterpoise-arm, formed of one strong piece of cast iron, and strengthened by the stays, 14,9119 Wis the weight, and C the counterpoise, formed of a greater or smaller number of cast-iron discs, according to the weight. PP is a platform for the workmen, suspended about three feet below the arbours of the winches It is formed of planks, and is the only timber about the machine. ad, bluew visione By working the winches, aa, the Weight, W, is raised or lowered by the chain which passes over the truckpulley, f, and is passed two turns round the barrel, c. In order that the power of the crane may be always the same, the chain is coiled, not upon this barrel, but upon the flanch-barrel, d, which is worked by the winches, ee, additional power. vd boneral " and may, in some cases, be used as an A chain from the truck, f, passes over the pulley at E, and is hooked on the barrel, h, below; and another chain from the truck-roller, g, passes over the pulley at G, and is hooked on the same barrel below. Any link of these chains hooks on the barrel, so that when the crane is to be loaded, the counterpoise, C, and weight, W, may be placed in equilibrio. By working the winches, u, so as to coil the chains upon the barrel, l, the trucks, fand g, and couequently the weights and counterpoise, are drawn towards the extrethe same winches in the opposite dimities of the arms, and by working rection, they descend towards the centre by their own weight, preserving their equilibrium, When the crane is to be raised or lowered, a chain is made fast to the arbour of the barrel, c, passing over the pulley, at B (as shown by the dotted line, fig. 1), to the barrel, h; then, by working the winches, ii, so as to shorten the chain, the crane is raised,and by working so as to lengthen the chain, the crane is lowered. The crane is turned round by pulling a gyrope attached to the chain close by the weight W; and by the combination of motions, the crane is made to stand quite firm upon its cross foot, while the weight is brought with readiness and precision from any depth below, and to any point within the range of the arm, DE, traversing quite round, BALANCE-CRANE, OR APPARATUS FOR LIFTING HEAVY GOODS. BALANCE-CRANE, OR APPARATUS FOR LIFTING HEAVY GOODS. We *། ༥ copy the following account of a most ingenious, though simple Apparatus for lifting heavy Goods from the Ground into Carts or Waggons, invented by Mr. J. W. Boswell (the celebrated improver of the Schemnitz engine for raising water), from No. I of the Repertory of Patent Inventions, a new and greatly improved series of the old Repertory of Arts and Manufactures.-EDIT. funde It has often appeared to me, that society would be much benefitted by communications published relative to useful matters which may have occurred to individuals in their several pursuits or employments, and which, from various circumstances, they may not be able to render lucrative to themselves by the exclusive right of a patent, or other means, though valuable for their application to purposes of acknowledged utility. "Influenced by this opinion, I have communicated several papers, which appeared to me to contain matters of this description, for publication at various times, and should have transmitted others, but have been prevented partly from the pressure of my business, and partly from considerations with which it is not material to trouble your readers. 4. Some of these I have had the satisfaction to see adopted by gentlemen who had more opportunity to turn them to practical utility than I had. One gentleman, who made use of my improvements on the Schemnitz engine for raising water, has had the liberality to acknowledge his having taken his ideas from my paper relating to it in Nicholson's Philosophical Journal, in "what he published respecting this matter; and another gentleman has done me the honour to take out a patent lately for my method of moving ships by compressed air, which was published in the Number of the Repertory of Arts for April, 1815, which, however, I presume, cannot be of much use to him, as, by this publication, I have not only established the priority of my claim to the invention, but, of course, have rendered his patent null and void. "These two instances will, I hope, give some proof of what I have asserted relative to the value of such publications, and excuse me for again taking up some more of your pages with similar communications. 259 "Having had occasion, some time back, to send off several large castiron vessels, some of which weighed considerably more than a ton weight, and not being provided with a crane to lift them into a cart, I had to contrive some method for the purpose, less expensive, troublesome, and dangerous, than the united efforts of a number of men. and some strong cord that had served I had some deal spars, a few planks, for binding pearlash casks, but nothing else that could be at all applied to the use desired; with these, however, I made a shift to construct an extemporary apparatus, which I found extremely convenient for my design, very simple, easily put together, and of no cost, and which, as others may find it, or one of a similar kind, equally serviceable, I will describe at large, With three spars I erected what is commonly (though improperly) called a triangle, united together by cords at top, and diverging sufficiently at bottom to make it steady; to the top of this I fastened, by several rounds of rope, a strong beech plank by the middle, placing it edgeways (or with its plane vertical to that of the horizon), which plank was near 14 feet long, 10 inches broad, and about 2 inches thick; to one end of this plank I fastened a large scale, used for weighing, and secured it well by triple cords at each angle. I then brought down the other end of the plank sufficiently low to raise the scale above the level of the cart, and in this position had it bound firmly by several rounds of cord to the vessel which I desired to raise: I then had the scale loaded with heavy matters (weights, pieces of iron, and bricks), till it balanced the vessel, after which it was easily raised and placed in the cart, by backing the horse till it came under it in the proper position; and then, by taking the weights out of the scale again, the apparatus was as readily disengaged. "I found this simple apparatus so convenient for loading carts, that I used it several times afterwards for lifting casks of Epsom salts, and other matters, under 200 cwt.; which leads me to suppose, that one on the same principle would be found very useful for raising any weight greater than what one man could lift with facility, and that it would be advantageous to have one erected permanently for the use of any business where heavyweights are required to be raised from the ground into carts or waggons. 260 ON THE USE OF THE SLIDING RULE. a defect, from which this, which I propose here, would be free, which is, they require very near as much time to raise a small weight as a large one; for though the winch, or other operating part, which puts the machinery of the crane into motion, may be turned round somewhat quicker for the small weight, yet, as it must be turned round an equal number of times in both cases, the different degree of speed which a labourer will use with a smaller weight will not be found of much benefit; whereas, with the balance crane, the time το the load to be lifted; ten hundred weight only requiring half the number of weights to be lifted which would be necessary for a ton, and a smaller load proportionally less. must be exactly proportionate labour "When an apparatus of this kind is wanted for permanent use, I would recommend the following alterations to be made in its construction. Instead of three spras placed as before described, a single post might be fixed erect, about 10 feet high, and be well secured from inclining from the perpendicular position by the usual means; in the top of this post a hole should be bored vertically, 14 foot deep at least, and be secured by an iron cap well fastened, having an aperture directly over the hole; the use of this hole is to receive the shank of a piece of strong iron, forked above to receive the centre of a balance beam, and having holes in the forked parts for a gudgeon to be passed through them and the beam; a scale should be fastened well by chains to one end of the beam, so as to be about four feet from the ground when the "I have seen some cranes where this load is fastened to the other end of the defect was attempted to be obviated, beam, or a little higher than the bot- by having two or three toothed wheels tom of a common cart, and the other of different sizes on one axle in the maend of the beam should be furnished chinery of the crane, so fixed, that the with a short chain and hook, for taking pinion turned by the winch or handle up any packages or other matters which of the crane might be transferred from were required to be raised into carts. the wheel of the larger diameter to that A number of half-hundred weights of the smaller size, when required for should be also provided, equal collec- a smaller load; but it is obvious that tively to the weight of any package this contrivance could have but a very usually sent off the premises, The narrow limit, and only vary acsquare half-hundreds, which are made cording to the wheels placed with a handle sunk in the body of the for that purpose, the addition of which weight, would be most handy for this proportionally increased the expense of purpose, as they could be readily piled the crane, and its complication, while one on another in the scale, when re- the principle of the balance crane enaquired, without any danger of falling bles it to vary its power, and the time off. Weights of other sizes might of the operation, exactly in proportion doubtlessly be used for the same pur- to the load, without any complication pose; but it seems to me, half-hundred of parts, or additional expense of conweights could be raised quicker into struction. the scale than larger or smaller sizes, for a given load, by men of ordinary strength. It will be obvious, that the use of the forked support for the balance beam having a shank descending into the body of the post, is to admit of the beam being turned horizontally, for the greater convenience of putting goods into carts, while they remained in a fixed position; for which reason the shank should be well rounded above, and fit properly in the cap, and should also have a socket let down into the body of the post to sustain its lower extremity, to admit of its being turned round with more facility. "I have a plan for another crane on similar principles, which I think considerably superior to those described here, when intended for constant use; and which, when wanted for raising great loads frequently, would cost but little more than the last; but to make this known as it should be, I must wait for some better opportunity." ON THE USE OF THE SLIDING RULE. (Concluded from page 228.) PROBLEM XI To find the number of ale gallons contained in a cask, from having the length and mean diameter given. RULE. Set the length on C to the guage AN INQUIRY INTO THE STRENGTH OF MAN. point (marked AG) on D, then against the mean diameter on Dis the content on C'in ale gallons. 261 to the point where the outside also of the cask meets it; then take half, their sum, to which add its twentieth part for the mean diameter, and this rule is founded on actual experiment on several casks of different forms and dimensions, and compared with actually filling the casks afterwards, and not from any theory which supdetermined figures, which is never poses the casks to be of regular and the case, as the inside is left by the workmen very irregular, as well as the form itself depends, in a great measure, on the fancy of the workman. I shall here conclude the description of the common carpenter's sliding rule, as what has been shown will, I trust, enable the workman to perform any operation he may have have occasion for, as well as thoroughly to understand its construction. I shall, however, at some future time, extend this article by a description of some other Rules, and particularly one called the Improved Sliding Rule, which, though not in general use, is deserving the consideration of the practical mechanic, and which, by the assistance of an extra slide, is applicable to almost every purpose of mensuration or arithmetical calculation. I am, Sir, yours truly, 239 262 AT: MESTI EHT DIXIT 23 sonład azad an de " muscles of his shoulders and arms have strength enough to raise all the weight. man sus as Although the muscles of each part of the body are able to make such great efforts to raise burdens, and though the spirits which swell the muscles serve to motion in general, by contracting themselves and drawing the tendons of their extremities, and may distribute themselves equally into all those parts, in the ner with a separated part, yet we must not compute the strength of a man by that of all his muscles together, seeing each part usually serves for a support that to which it is joined. For example, the muscles example, the muscles of the arms and shoulders, contracting themselves, can raise a weight of 160lbs.; but if the body be bent, the arms cannot sustain this weight, unless the muscles of the loins have strength, at the the same time, to su tain the upper part of the body with the weight with which it is loaded; but if the hams were also bent, then the muscles of the legs thighs must still make a greater effort, a they must sustain the weight of 160lbs., and at the same time that of the whole body. Whence it happens, that in this disposition of the whole body, the strength is divided by Loby the distribution of the s all the parts, which is the cause Je spirits into that a man cannot raise from the ground a weight of 160lbs." Not but there may be some men whose spirits flow in such abundance, and with so much rapidity, into their muscles, that they make efforts triple and quadruple of what is s usual; and this appears t me the natural reason of the surprising force that we see i in some men who carry and lift such burdens as two or three men together would be at a loss to support, though these men are sometimes of a moderate size, and seem outwardly rath weak than strong. There was one not long ago in this country, who was said to carry a great smith's anvil, and, of whom several wonderful actions were related; but I saw another at Venice, who was young, and did not seem to be able to carry above 40lbs, or 50lbs., who, getting upon a little table, raised an ass from to |