of the Boston Journal' thus describes it:-It is a simple wheel, runs on gudgeons, and is independent of any outside spring, weight, or power as a propeller. On the same axle on which the metal wheel is fixed is a band wheel, on which a band runs over a small pulley that drives a small circular saw. Set it on a table and remove the brake, and it will start itself and run with great velocity, driving the circular saw. It is the simplest thing in the world, though I cannot intelligibly describe it; but it is at once understood by the beholder. It will not, nay, cannot, stop without a brake, as it is so fixed by means of balls and arms that the descending side of the wheel is perpetually farther from the centre of motion than the opposition ascending.

In 'The Times' of the 2nd June, 1864, appears a communication from 'A Herefordshire Incumbent' on 'Authoritative Decisions,' in which the writer incidentally observes :—

The desire for certainty is an instinct of our nature, and the motive spring of all discovery. No sooner does any question really interest a man than he sets about seeking for a solution of it, and does not stop till he either finds one that satisfies him, or discovers that the nature of the question renders a solution impossible-a result which is, in fact, one form of answer. Newton probably never rested from the time when the fall of an apple excited his attention to the moment when the law of universal gravitation unfolded itself to his mind. No doubt scores of persons, of imperfect education but a mechanical turn, are engaged at this time in the attempt to effect perpetual motion, and will go on till they die, unless they should have the good fortune to fall in with a mathematician who can teach them both that what they are aiming at is an impossibility, and why it is so.

A correspondent, W. T, in 1868, claimed to have discovered the great mechanical secret of perpetual motion, and which had led him to the invention of a peculiar arrangement of pumps, first to be started by a winch handle, and then to continue working. He suggested a plan like the two cylinders A, B, of corresponding capacity, but differing in form, as shown in the diagram annexed, each having pistons and piston rods, with corresponding cranks, C, D, on an upper

axle, supported by strong frame-work. It would be difficult to conceive anything less imposing, or more impossible.

B

J. P, a Scotch mechanic, in February, 1870, writes to state that he cannot form any theory to explain why a system of a kind of water-bellows, set around the periphery of a wheel, should not, when filled, press themselves empty as they pass over a roller, thus causing a water-wheel, on such a principle, to be heavier on the one side than on the other. The idea is a reproduction of Vogel's plan, already described, but slightly modified. In describing his draught, he says:-A, a wheel, turning on its axis B, and passing over a roller D.

C, sixteen chambers, containing water, and communicating with each other by valves, which open only in the direction of motion.

E, sixteen bellows, opened by a light spring, and closed by passing over D.

As the bellows is closed, the air with which it is filled is forced through a valve opening inwards into an elastic bag, or bellows, within the chamber, and the air is retained in the bag by the closing of the valve. It escapes slowly by a small hole in the centre of the valve itself, and thus the chambers on the ascending side have all more or less air in them, whilst

those on the descending side are all quite full of water. In a wheel carefully contrived on this principle, would not the

constant extra weight on the descending side be sufficient to overcome the necessary pressure below? There might, of course, be several ways of closing the outside bellows, involving less friction than the one rudely sketched.

The Scientific Review,'* of 1870, notices a contrivance closely allied to the foregoing, of which it is stated that the invention of Mr. W. D. STILES, of Nevada City, consists of an old plan of arranging a series of hydraulic bellows around the perimeter of a vertical wheel, and operating them by means of cams on the spindle upon which the wheel runs, so as to force the water from one bellows into another at certain points of the wheel's revolution. The weight of the water thus transferred from one point of the perimeter to another rotates the wheel and furnishes the motive power.

Mr. R. S, lately deceased, wrote the following paper :Does Perpetual Motion admit of a Mathematical Solution?It is, perhaps, the most difficult and still seemingly easy question that can be put. Perpetual motion has for ages * Scientific Review,' vol. v., No. 3. Folio. March 1, 1870. London.

been the study of a large portion of the mathematical mechanical, who during some portion of their lives have given a large share of their time to the subject; and the result of those labours has been of the most discouraging nature.

Were it possible to answer the above question, the whole subject might be set at rest; or, if a professor of mathematics could satisfy the student in search of perpetual motion that he was seeking a chimera, what a benefit he would bestow upon him.

In considering the subject, it is first necessary to know what perpetual motion is to the mechanic; and, in order that it may not be made too intricate, let that machine stand for the question that will turn by gravity alone which is selfcontained, then the question will be as follows:

Can a machine move, or keep moving, after being set in motion by the arrangement of weights about its centre, periphery, or elsewhere?

Now, it will be seen that all the quantities are unknown, and to obtain an equation it will be necessary to suppose everything, hence the difficulty, for it is evident that it is as easy to suppose it possible as impossible.

It is quite another matter for the mathematician to prove the impossibility of a machine moving by gravity, such as above named, when the proportions are given as well as the position of the weights, if fixed, or their paths, if movable; then, however, a model or a series of comprehensive drawings will do as well.

Consequently from the foregoing, perpetual motion is, as it has ever been, an open question; and no doubt will engage the attention of the mechanical philosopher till his patience be worn out; for to believe a thing impossible that has baffled the most learned to prove so, can hardly be expected.

CHAPTER XI.

PATENTS OF THE NINETEENTH CENTURY, FOR IMPROVEMENTS IN OBTAINING MOTIVE POWER; ENGLISH AND FRENCH.

It would scarcely be credited, without the facts here prominently brought forward, that the last three-quarters of a century should have given rise to the obtaining of letters patent for about 170 motionless mechanical contrivances, combining levers, wheels, weights, water, and air, to accommode the whimsical fancies of men pretending both to rationality and some scientific knowledge. It is truly to be deplored that, in this enlightened age, there should be found such palpable proofs of men lavishing their time and money on this chimerical pursuit. Here we have a class of patentees who fearlessly parade their ignorance and folly before the public; ignorance, because the most elementary acquaintance with the subjects in which they dabble ought to suffice to expose their ill-masked points of failure; and folly, because their greatest success could at best only realize a worthless curiosity.

We shall proceed to give the patents in order of date, including those which were omitted to be noticed in 1861 :—

1801.-WILLIAM PARKES [No. 2535], of Newington, Surrey, Professor of Philosophy, "A perpetual power that will give motion to all kinds of machinery, mills, engines, carriages, ships of war, mercantile and other vessels, lighters, crafts, and boats of every description."

This grand arcanum or secret of nature is that liquid or fluid composition called air, not formed by art but by the chymical process of nature. It is invisible and inexhaustible, but it is unlimited in its power and effect. It can be applied