James White

“ If this Machine is well made and proportioned, I think it is one of the best that can be used, to do much work by a given power: It gives no shock to the water; which, when once in motion, continues to rise, and escapes when arrived at it’s proper height: and, being spread over a large surface, no part of it is raised higher than enough. The perfection of the Machine depends on a due relation between the centrifugal force, and the sine of the angle, which the threads of the screw make with the horizon ”

“ When a wheel, in general, rolls on or against any fixed plane (and the cords m P, A P, now act the part of a fixed plane) , the point of it’s circumference the most distant from that plane, moves, in a direction parallel to it, just twice as fast as the centre of such wheel, because it is twice as far from that plane, the virtual centre of its motion: (an example of which is found in the wheel of a carriage, whose top moves forward just twice as fast as it’s axle-tree.) ”

“ The action of a wheel of the new kind on another with which it works or geers is the same at every moment of its revolution, so that the least possible motion of the circumference of one, generates an exactly equal and similar motion in that of the other. ”

“ A sugar-mill acts in or near the plane of the centres; and one of it’s cylinders is not intended to drive the other independently of pressure between them. This is so true, that the rollers of many sugar-mills are not fluted at all. Besides this, my wheels exert no pressure in that direction; and if they did, they would not be cog-wheels. In a word, their action is at right angles to the former, and has an object of quite a distinct nature. These, then, are by no means the same machine; and, therefore, mine is not a “Chinese Invention.” ”

“ It is however vulgarly said that power cannot be gained without losing time—which implies that if time is lost, power will be gained: and the principle of virtual velocities says the same thing, though in more appropriate terms—that if a small movement be given to a system of bodies actually counterpoising each other, the quantity of motion with which one body ascends, and the other descends perpendicularly, will be equal: so that, as remarked in page 50, by “whatever means a slow motion is obtained, dependent on that of a moving force, the power is great in the same proportion.” ”

“ The knife-edges which carry a heavy pendulum, suffer it to vibrate many years without wearing out; and the fulcrums of scale-beams, bear enormous weights, for almost an indefinite period, without any injurious effect. I request therefore, that these facts, may be put into the scale, when my foregoing statements are tried: whether as applied to these anti-attrition machines, or to my late patent wheel work, or both combined: for I foresee the use of these friction rollers, cut into teeth on that principle, to insure the proportionality of their respective motions. ”

“ If in unloading a vessel, there should be found goods of every weight, from a few hundreds to a ton and upwards, the workman will be able so to adapt his strength to each, as to raise it in a space of time, (inversely) proportionate to it’s weight, he walking always with the same velocity as nature and his greatest ease may teach him.’”
“‘It is a great disadvantage in some Cranes, that they take as long a time to raise the smallest weight as the largest; unless the man who works them turn or walk with such velocity as must soon tire him. ”

“ The Slide-valve is an excellent substitute for the hand-geering of steam-engines, from the simplicity of form which it introduces, and the certainty of it’s recurring effects. But it is, I believe deservedly, reproached with being too sluggish in it’s operation, at the very moment when activity would be most desirable—namely, at the beginning of the strokes; insomuch, say some, that the power of the engine is materially lessened by it. The fact is, that the excentric (usually placed on the crank-shaft) is almost always moving, and with it the slide-valves also ”

“ For if the number of the teeth on these wheels (A and C) differ only by unity or one, then must the handle D revolve one turn about that common centre to occasion 1⁄100 part of a revolution of the wheel A, and of course 100 turns to move the axis B once round that centre. And if further the wheel A be three times the diameter of the axis B, the power gained there would be as 300 to 1, [75] that is a power of 1lb. at a distance from the centre, only equal to the radius of the wheel A, would countervail a weight of 300lb. suspended on the axis B: and supposing a man’s strength to be 100lb. ”

“ When any part of a line requires a dot or mark to be made, the Machine strikes a blow there; and when no impression is to be made, the Machine (by means that will be shewn) suffers the cylinder to pass that place without striking. The means of regulating this is committed to workmen who merely know how to read off the pattern in it’s length, as it is now read off in it’s width by the weaver. To describe the construction of the Machine, (as exhibited in figs. 3 and 4 of Plate 50) A is the cylinder to be engraved; and B is a worm-wheel fixed to it’s mandril, and destined to turn it. ”

“ To keep a Door strongly closed, yet suffer it to be opened easily. That “necessity is the mother of invention,” is a remark none the less true, for having become a trite proverb; I could mention the time, place, and circumstance which gave birth to this little Invention: but such detail would be superfluous. A certain door was, and is still, most inconvenient, from the stiffness of the spring, and the noise it occasions in a place where silence ought to prevail: which state of things suggested to my mind the Machine represented in fig. 5, of plate 17. ”

“ But should it be desirable to engrave patterns so correct as to require an exact parallel motion round the cylinder, then the motion of this screw must not be continual—but must intermit and be resumed, at every beginning of a new line round the cylinder. I hope, I make myself understood: a pattern drawn on squares, produces lines all parallel to the first; while the spiral motion of the punch causes a slight deviation—which, in a word, can either be suffered or avoided. At all events, this deviation is so much the smaller as the punch motion is slower in both directions ”

“ With regard to the demonstration of the first proposition, I must premise an observation of M. Camus on this subject, in his Mechanics, 3d. part, page 306, viz. “if all wheels could have teeth infinitely fine, their geering, which might then be considered as a simple contact, would have the property required, [that of acting uniformly] since we have seen that a wheel and a pinion have the same tangential force, when the motion of one is communicated to the other, by an infinitely small penetration of the particles of their respective circumferences.” ”

“ They have done more; they have given birth to machines of no small importance, that could not have existed without them. In rapid motions they do all that band or cord can perform, with the addition of mathematical exactness, and an important saving of power. In spinning factories these properties must be peculiarly interesting; and in calico-printing, where the various delicate operations require great precision of motion. In clock-making also, this property is of great importance in regulating the action of the weight, and thus giving full scope to the equalizing principle whatever it be. ”

“ But I may be opposed in some of my statements by the fact, that friction rollers, with centres, have been used with little advantage; and often laid aside. This I acknowledge; and go a step further. Friction is by no means of so much consequence as it was once thought to be: and is not the source of the greatest defalcations that occur in the use of power. Yet, to get rid of it, in some cases, would be of considerable importance; and the subject deserves at least the attention of every intelligent mechanician. ”

“ But the pressure is not the same. For, the line a g is the direction in which the pressure of the curve acts at the point g, and the line p q, is the length of the lever-arm on which that pressure acts, to turn [95] the generating circle on its axis (now supposed to be fixt;) but, as the turning force or rotatory effort of the wheels, is by hypothesis uniform, the pressure at g must be inversely as p q; that is, inversely as the cosine of half the angle of rotation of the generating circle; hence it would be infinite at s, the summit of the curve, when this circle has made a semi-revolution. ”

“ In the use of bevel wheels of this description (with singly inclined teeth) there is doubtless a tendency to approach toward or recede from each other; the extent of which (for cylindrical wheels) has been already determined. This tendency goes, so far, to give a bend to the shaft; and, if this be very weak, to create a degree of friction on the teeth as the wheels revolve. It is therefore desirable that the shafts should be rather too strong than too weak; since the principle can only exist entire, when the wheels in working, are kept in the same planes which they occupy when at rest. ”

“ Nevertheless, these threads are made to occupy the same length, in both screw and nut, as though they did enter each other: so that the two parts running parallel to each other, leave a square interstice b, all along both nut and screw: into which balls of brass, or soft iron are [82] introduced, which at once restore the screw-property without it’s friction: a friction so considerable in the common screw, that it always surpasses the effective power, since it remains closed, (in a vice for example) while holding any object squeezed with all the force a man can apply. ”

“ I believe there is no better floor for a working horse to tread on, than a plane of wood—on condition, of the horse being rough shod: I speak however, on recollection of many years’ standing. I then felt persuaded that a horse wastes less effort by travelling on this floor than on any other; which is one of my reasons for the adoption of the present Machine. It consists (Plate 26, fig. 1,) of a wheel A B, on which the horse walks, as indicated by the sketch of him given in the figure. ”

“ One man’s weight applied to the extremity of the wheel would raise upwards of a ton: and it need not be added that a single sheaved block (at the jib) would double that power. Suffice it to say that the size of the machine may be varied in any required degree, and that this wheel will give as great advantage at any point of its plane as a common walking wheel of equal diameter; as the inclination can be varied at pleasure, as far as expediency may require. ”

“ This Invention has for it’s object, to make a more abundant use of the wind’s agency, at a given expence, than is usually done: and the means, generally, are to avoid a part of the expence lavished on the foundations or fixtures of wind-mills, and yet to carry more sail than that system admits of. Machines of this nature, are chiefly used in low marshy countries, where there is much water to be raised, and little solid ground to build on. My idea here, is to found the whole on the water, and to make that element the medium, and as it were the centre of every motion. ”