had been placed in a situation which enabled her to realise a sum sufficient for their future comfort; and at the death of the good Madame St Alois, the younger Maxwells were amply provided for by the bequest of all her savings.

JOHN SPENCE, A NATURAL MECHANICAL GENIUS. JOHN SPENCE was the son of a tanner in Linlithgow, and from the early age of four or five years, exhibited a taste for mechanics. He could not study the subject in books, from his ignorance of the technical terms, but, as he grew up, he cultivated his favourite propensity by visiting many and various machines, observing them in motion, and meditating on the principles developed in their construction. Wheels and levers occupied all his boyish thoughts, and he was happy only when inventing, and constructing what he invented. At the age of twelve, he was sent to a shoemaker to learn that business, but was never indentured. Such was his readiness in taking up any handicraft employment, that, after looking on for a week or two in the shoemaker's workshop, he began the trade at his own hand, requiring no further superintendence to teach him its whole mystery.

Some years afterwards, having imbibed a dislike to the shoemaker trade, and being desirous of getting near some of the great machinery in Glasgow, John Spence went to that city, and made an unsuccessful attempt to procure employment in some of the factories there. He then returned to Linlithgow, where, to his great satisfaction, he obtained the humble place of keeper of a small steam-engine. His duty here was to oil the machinery and feed the furnace; and though his friends were altogether unable to conceive what pleasure he could find in such an occupation, he felt perfectly happy in it, from the opportunity it afforded him merely of seeing

wheels in motion. Tired at length with the sameness of the scene, Spence, at the end of two years, returned to the trade of a shoemaker. But the mechanical powers still haunted his imagination, and he continued to invent and construct, neither to the benefit of his purse, nor to the satisfaction of his friends and his wife. In 1814, he was so much disgusted with the shoemaking, that he resolved to try the weaving trade. He constructed the whole apparatus of a loom, except the hiddles and the reed, got a professional weaver to put in the first web, and, without any other instruction, made cloth not distinguishable from the manufacture of those regularly bred to the business.

A restless desire to accomplish something of greater moment in the mechanic arts, appears to have soon led Spence away from the weaving scheme. Among other curious subjects, he turned his attention to the invention of travelling machines, where the moving power was to be supplied by the traveller's hands or feet. He came from Linlithgow to Edinburgh in a car of this kind, which was afterwards exhibited in the latter city. This car stood on four wheels, and could hold three persons, two of whom wrought at a time in propelling it by means of two handles acting on the wheels, and which handles revolved like those of bucket- wells or milk-churns. Various other machines, evincing much mechanical ingenuity, were invented by John Spence, but we are unable to describe these in detail, and now turn to the great feat which brought him into general notice, or rather, notoriety.

Spence was just the man to be tempted into the pursuit of the Will-o'-the-Wisp, called the Perpetual Motion. His scientific knowledge was too limited to guard him against the delusive belief in the practicability of such an invention; and the honours which would undoubtedly attend success, formed a most seductive prospect to his ambition. After directing his ingenuity long to this difficult point, he at last announced to his friends in Linlithgow, that he had attained the object of his desires.

This occurred between the years 1814 and 1818. After a time, the intelligence of the ingenious Linlithgow shoemaker's discovery of the perpetual motion spread generally over the country, and great numbers of strangers, scientific and otherwise, visited his house, and saw his machine. Everybody admired the ingenuity and seeming simplicity of the contrivance. In the Edinburgh Magazine for May 1818, a description of the invention is thus given. After stating the difficulty of explaining it clearly, the writer proceeds :- Suffice it to say, that a wooden beam, poised by the centre, has a piece of steel attached to one end of it, which is alternately drawn up by a piece of magnet placed above it, and down by another placed below it; and that, as the end of the beam approaches the magnet, either above or below, the machine interjects a non-conducting substance, which suspends the attraction of the magnet approached, and allows the other to exert its powers. Thus, the end of the beam continually ascends and descends betwixt the two magnets, without ever coming into contact with either; the attractive power of each being suspended precisely at the moment of nearest approach. As the magnetic attraction appears to be a permanently operating power, there appears to be no limit to the continuance of the motion, but the endurance of the materials of the machine. The novelty here, it will be seen, lies in the ingenious manner in which the magnetic power seems to be rendered inoperative, at the proper moment, by the intervention of the non-conductor. The magnet had often been thought of as the source of a perpetual movement, but Spence had the merit of inventing this mode of bringing it into play.

Such are the principles upon which the perpetualmotion machine of Spence was ostensibly constructed. Being seen by several persons of eminence, the inventor was recommended to bring his wonderful engine to Edinburgh, for exhibition before the great ones of the capital. He adopted the advice given to him, and came to Edinburgh in the middle of the year 1818. He at

once excited the greatest attention among the scientific people, some of the most eminent of whom seem to have sincerely adopted the belief that Spence had succeeded in discovering the grand desideratum. The whole world ran after the extraordinary shoemaker of Linlithgow. The great machine itself was, after a time, shut up in a convenient place (on the Calton Hill, we believe), in order to test the perpetuity of its movements, and it was there visited by thousands. Drawings of it were exhibited in the streets, and the ingenious sect of the phrenologists examined the inventor's skull, where they found everything to coincide with the possession of great mechanical genius. There is one point in the report of the phrenologists upon Spence's head, which strikes us as extremely naïve, considering what came out afterwards. I found,' says the phrenological reporter, that he had a very large development of cautiousness;' and afterwards, 'so far as I have been able to observe, he is very cautious; and some persons who have been attempting to impetrate his secret from him, regarding the perpetual motion, will be able to confirm my testimony from their own experience. When addressed himself on the subject, Spence said: 'You may judge yourself whether I am cautious. All this, though reflecting credit rather than otherwise upon phrenology, tends to excite a smile when one considers how little Spence's real reason for caution and concealment was thought of at the time; for, after a season, the perpetual movement came to a pause, like all earthly things! The inventor had permitted no one to examine the interior of the machine, and was himself excluded from doing what he chose to it; and, in consequence, the movement came to an end, after having continued for about a month. It was then found, that the operation of the magnetic power was merely the ostensible cause of the movement, and that the real source was a large spring in the interior. The machine ran out in the same way as does an eightday clock.

The deception which Spence had practised was certainly

an unjustifiable one, and he was punished for it, by losing all the credit which his real ingenuity entitled him to. Notwithstanding this unfortunate declension, the mechanical shoemaker continued to indulge in his favourite pursuits. He turned his attention, among other things, to the construction of velocipedes, or horse-like machines, where the rider fulfils the double part of horse and horseman. On a machine of this order, consisting of two wheels, one behind and one before, with an intermediate bar, shaped like a saddle, in the centre, Spence once travelled between Edinburgh and Glasgow. He propelled himself by pushing his feet occasionally against the ground, and could keep up for a mile or two with a gig, going at a common pace. Although an unpractised person, from the narrow base presented by the wheels, could with difficulty balance himself on this machine even in a seated posture, Spence had acquired by practice such dexterity in managing it, that he could stand on the saddle on one foot, and with the other projected in the air as a balance, guide the engine down a declivity of nearly a mile in length, going all the while at a bounding pace. For some time he contrived to draw a little money by shewing this velocipede, and teaching people to ride on it, in a court-yard which he rented for the purpose.

Another production of John Spence's ingenuity was a house-a wooden house, which he erected at Fountainbridge, a suburb on the south-west of the Scottish metropolis. This house was twelve feet square, and consisted of three floors, reckoning a cellar and garret under that denomination. Twelve posts or standards, each about four inches square, composed the solid supports of the building, and these were clad outside and inside with deals, forming the walls. The space between might be filled up with any loose stuffing to increase the warmth within. An excavation beneath formed a cellar. The roof was of wood, and a trap-stair led from the main floor to the garret. The materials of the house were bound together by long screw-bolts, where required. This house was perfectly portable. Spence took it down