Improved Kettle-Holder. surface, while those that are least pressed on are lengthened, and rise above that level. As soon as the former columns have sunk to a certain depth, and the latter have risen to a certain height, their motions are reversed, and continue so till the columns that were at first most depressed have become most elevated, and those that were most elevated have become most depressed. The alternate elevations and depressions thus produced are called waves. The water in the formation of waves has a vibratory or reciprocating motion, both in a horizontal and a vertical direction, by which it passes from the columns that are shortened to those that are lengthened, and returns again in the opposite direction, progressive motion not being necessary to undulation. The vibrations of water in the form of waves may be compared to the reciprocations of the same fluid in a syphon or bent tube; and it was from this that Newton deduced the velocity of waves, and the time required for an undulation. The time of an undulation is the time from the wave being highest, at any point, to its being highest at that point again. The velocity of the wave is the rate at which the points of greatest elevation or depression seem to change their places. If the altitude and breadth of a wave be known, the time of an undulation and the space which the wave appears to pass over may be determined as follows:-To find the time of an undulation, add half the breadth of the wave to its altitude, multiply the sum by ⚫3927, and the square root of the product will be the time in seconds. (This number is oneeighth of the circumference of a circle whose diameter is 1.) Thus, suppose the breadth of a wave to be 14 feet, and its heighth 3 feet, required the time of an undulation. Here the sum of the height and half the breadth is 10, which multiplied by 3927, becomes 3.927, the square root of which is 2, nearly, the number of seconds in which an undulation is performed. To find the space which the wave passes over in one second :-Divide half the breadth of the wave by the square root of the altitude, and half the breadth, multiplied by 3.927, and the result will be the space passed over by the wave in one second." Thus, suppose the breadth and height of a wave to be as stated in the preceding example, and it is required to find the space it will pass over in a second of time. Here the square root of 10 is 3.1, nearly, which multiplied by 3927 is 1.22, nearly; and 7 divided by this number quotes 5, nearly, 77 While the depth of the water is sufficient to allow the oscillation to proceed undis. turbed, the waves have no progressive motion, and are kept, each in its place, by the action of the waves that surround it. But if by a rock rising near the surface, or by the shelving of the shore, the oscillation is prevented, or much retarded, the waves in the deep water are not balanced by those in the shallower, and therefore acquire a progressive motion in this last direction, and form breakers. Hence it is that waves al. ways break against the shore, whatever be the direction of the wind. Breakers formed over a great extent of shore are distinguished by the name of surf. The surf is greatest in those parts of the earth where the wind blows always nearly in the same direction; but in the foregoing observations no allowance is made for winds. H Improved Kettle-Holder. By G. J. [From the London Mechanics' Magazine.] SIR, A B is a slender bar of iron, or strong piece of hooping. A D, BE, are hooks of equal size fixed at A and B; but E B is prolonged upwards to D, where it is turned off square to form a handle. F is a hook, admitting of being turned freely round its centre-pin C. The hook F is hung on across the pot-hook, and the kettle on the hooks D E; there is also a spring, which is welded on A B, and entering the mouth of the hook E, prevents the kettle from slipping. The operation, then, is to draw the handle D towards you, when the water will Hunter's Screw Press Improved. By . M. [From the London Mechanics' Magazine.] SIR,-I beg leave to submit to the consideration of your readers the following design for extending the range of an admira. ble invention, which must be familiar to most of them-I mean Hunter's Screw Press. My principle is, instead of using Hunter's triple combination of nut and screw, to use only a nut and screw with a supplementary apparatus, which shall have the effect of making the screw, as it were, run away from the grip, of the nut, while the nut is made to follow with whatever degree of velocity may be required. Thus the screw rises with a velocity bearing a similar ratio to that of the moving power, as in Hunter's, while the range of the resultant power is continued through the whole length of the screw. the accompanying figure, A' B' is the screw taken out of its place; a square projection of equal length with the scre is added to it. The head of this square part is seen in the figure at A, rising out of C, in which it slides. C is a tube with a circular bore, wide enough to admit the screw freely, but closed by a square aperture, through which the square projection works. C is of one piece with a, b, and c, and works resting upon d, which is the real nut. a, b, c, and d, are furnished with teeth, and a winch is affixed by a contrivance which will allow of its en. gaging either a, b, c, or d, individually, or c and d together. a may be supposed to have 50 teeth, b 100, c 200, and d 200. a, b, In order to get up one little hill, all the pas and c, are intended merely to bring the screw sengers were asked to get out and off from down to its work, or to perform light tasks; the coach, and even then it was with the and when the winch engages any one of greatest difficulty that the coachman could them, d is clamped. When the screw is re- force the horses up. He was obliged to quired to do its utmost, the winch is made to "lash them into madness;" sometimes two engage c and d together: then c, by means were down together, and once all four were of its hold on the square projection, keeps down at the same time, and when they had the screw going before the nut, while the nut scrambled to the top they were in a pitiable is overtaking it at the rate of one tooth for state of exhaustion, the sweat literally runeach revolution. The construction given in ning from them as though warm water had the figure is one of several, and not the best, been poured on their backs, although so cold but the one I found least troublesome to a morning. copy. I hope some of your correspondents will favor us with an opinion of the merits of the machine as thus altered, and also with a calculation of its powers, taking for data the winch at 15 inches radius, the moving power at 30 pounds, as also, that one revolution of the winch passes one tooth, and that one re. volution of the nut d passes one thread of the screw, the interval between any two threads being 2 inches. A Improved Horse Shoe. By T. P. [From the Voice of Humanity.] SIR, I was lately travelling in a coach, early in the morning: it was one of those mornings which are so distressing to smooth. shod horses. In the night there had been a considerable fall of sleet, with a little rain, aad this fall was immediately followed by a very hard frost, so that the road was one complete sheet of ice. Coming on so suddenly, there was no time to get the horses rough-shod, and their consequent suffering was great. They were down and up, first one and then another, all the way. It struck me at the time that it would be easy to make horse shoes which might be turned up, as it is termed, in a few minutes. I send to your appropriate publication a drawing of the sort of shoe I have invented. The two steel nuts, marked B, are made barely a quarter of an inch high, about oneeighth and a half, and wore in the winter when the roads are not slippery. When the frost comes, and you wish the horse turned up, or more properly speaking, rough-shod, you take out the two nuts, marked B, by means of the spanner, marked C, and put in the two steel nuts marked A. The whole is done in a few minutes. Mr. Holmes, the veterinary surgeon of this town, has lately shod some horses in this way, and it answers well. When the groom or ostler picks his horses' feet every night, he should at the same time take out the nuts, put a little oil or grease to them, and screw them in again tightly this is to prevent their getting fastened by rust. There should always be a little store of nuts, that as they wear down they may be replaced; and they must not be permitted to wear down lower than that state in which they can be turned out by the spanner. The prevention of the very injurious effects upon the feet of horses by their shoes being taken off and turned up (often required from frost in a day or two after they have been newly shod) is worth consideration, to say nothing of its being done in haste and the foot often pricked. Above all this, rational humanity and kind. ness to those docile, useful, and noble animals, should be our main object. Let them ever be considered as gifts from the Almighty Creator, for our use and comfort, and let them ever be treated with gentleness. Indeed, I believe they are seldom ill-treated, but by men of vulgar minds, unthinking, or uneducated; or if educated, their education not based on Christian principles, and, without that base, I hold all education defective, if not mischievous. Birmingham, Feb. 9, 1832. [From the London Mechanics' Magazine.] WALTER HANCOCK'S STEAM CARRIAGE.The engraving, above delineated, represents a new steam carriage, which Mr. Wal. ter Hancock has just built to run on the road between London and Greenwich. For the following particulars of its construction we are indebted to Mr. Gordon's valuable Historical and Practical Treatise, reviewed in our last number. There are two engines, which are placed before the boiler, and turned with the stuf. fing box down, so that the cylinders are uppermost, and the piston and connecting rods below. The crank shaft with two cranks is supported by a flexible frame, which provides for any concussion on rough roads. A chain passes over a sheave on the crank shaft, and over a larger sheave on the hind axletree. The wheels turn loose on the axle, and one or other, or bath, are fixed by a clutch when required. This clutch is on the outside of the wheel, and can be screwed out or in, as the case demands, with great facility. The turning of the carriage round to the offside is prepared for by throwing out the offside clutch and keeping in the near one; and the turn round to the near side is prepared for by throwing out the near clutch, and throwing in the offside clutch. A little play is left between the catches in each clutch, so that a winding road may not oblige either On the Strength of Men and Animals. of which there are two. B the fire-place; D the stoke-hole; E E the chambers, con structed of the best wrought iron; F F shows the manner in which all the chambers are bolted together, so as to form a large boiler of many compartments. There are fillets of iron, which keep the individual compartments at a proper distance from each other; and the spaces which these fillets leave are the flues of the boiler, through which the flames ascend, as shown at H H H. All these compartments are connected at the bottom for the purpose of keeping the water in each at the proper level; and at the top the steam is conveyed from each by as many pipes as there are chambers, into the steam feed-pipe, by which steam is conveyed to the engines. By this arrangement the only parts of the boiler which can be dreaded are the sides, but good ties will keep them together. And as to the bottom end and top of the boiler, which are composed of the edges of these compartments, if one part is burnt out or hurt, it is only that individual compartment which can burst, and its power of doing mischief is not worth notice. The fire is urged by a blower which is driven by a connection with the engines. 81 The waste steam is blown from the engines into the chimney, and so destroyed. The passengers are carried on the same machine, Mr. Hancock preferring that disposal of the weight to the dragging of it in a carriage behind. The wheels of the car. riage are a beautiful exhibition of strength and lightness combined. The spokes are all wedge-shaped, and where they are fastened into the nave abut against each other. Their escape laterally is prevented by a large iron disc at each end of the nave; and these being bolted through, confine the spokes se curely in their place. On the Strength of Men and Animals. [Se. lected for the Mechanics' Magazine.] The form and construction of the human body renders it peculiarly applicable as the first mover of machinery, and what it wants in strength is compensated in a great de. gree by the skill and judgment with which it can be applied. When we consider the great number of cases in which it is preferable to employ the action of men rather than that of inanimate agents, and the still greater number in which it is out of our power to employ any other, it becomes a matter of the highest importance, both to workmen and to those who employ them, to ascertain the way in which the greatest quantity of work can be obtained from their exertions, with the least quantity of bodily fatigue, or with such a quantity of fatigue as they can easily bear from day to day, without injuring their corporeal functions. Daniel Bernoulli, indeed, maintained that the degree of fatigue is always proportional to the quantity of action by which it is produced; that, whether he walks or carries a load, or draws, or pushes, or works at a winch, or raises a weight, he will always produce, with the same degree of fatigue, the same quantity of action, and therefore the same effect; and that the daily labor of a man, whatever be the work to which he is set, may be reckoned at 1,728,000 pounds, raised through the height of one foot, or 60 pounds raised through the height of one foot in a second, when his day's labor amounts to eight hours. These opinions were adopt. ed by almost all subsequent authors, on the authority of vague and inconclusive experi. ments, till the subject received a full investigation from the celebrated Coulomb, Amontons, and others. According to M. Amontons, a man weigh. ing 133 French pounds, ascended 62 French feet by steps in a minute, but was complete. ly exhausted. |