ELECTRO-MAGNETIC MACHINE.
The electro-magnetic machine invented by Professor Page, has from time to time been noticed in our Journal, and we have now to give a further account of this interesting mechanism, as furnished by an American periodical. It appears that several of these machines have lately been submitted to critical examination by competent authority at Washington, and with very favourable conclusions. The principle has already been explained—namely, the alternate rising and falling of an iron rod within a helix through which an electro-magnetic current is made to pass: when the current is on, the rod rises, and remains, as it were, self-suspended, equidistant from all parts of the surrounding helix; and falls as soon as the current ceases by breaking contact with the battery. The 'rod' of one of the machines submitted to the examination weighs 350 lbs.: no sooner, however, was contact made, than it rose into its position. 'Dr Page then stood on the top of the rod, which not only sustained his weight, in addition to its own, but he pushed with his hands against the ceiling, increasing the downward pressure on the rod, which was only acted upon as a powerful spring would have been, but still maintaining its perpendicular position concentric to the inner surface of the helices. I held,' says the reporter, 'an iron rod in my hand, with the end of which I touched that of the suspended rod. I could not detach it by pulling or jerking, and could only alter its position so as to cause the annular space to become eccentric instead of concentric. The instant the battery was disconnected, the rod fell to the floor with its full force.'
By moving the wires from the battery up and down outside the pile of helices, it was clear that an upward and downward movement of the rod would follow, 'and that a shackle-bar attached from this oscillating rod, and to a crank, would convert this reciprocating motion into a continuous one.' To this contrivance the name of 'Jumper' was given, of which one was exhibited, the helices weighing 800 lbs., and the rod 526 lbs.; and by the means above mentioned, it has been converted into a working-engine, with a twelve-inch crank, and a fly-wheel of four and a half feet in diameter. 'On the outside of the helices,' to quote the description, 'was placed a line of pieces of metal, so arranged as to render the attachment with the battery and its necessary alternations performable by the engine itself. Before starting the engine, I tied an arm of the fly-wheel, at one-third greater distance from the centre than the length of the crank, to an upright beam of twelve inches diameter, which formed part of the frame of the engine. The cord used was the better kind of bed-cord, of great strength, nearly three-eighths of an inch thick. This was passed twice round the fly-wheel arm and post before being tied, and with pieces of sole-leather intervening, to prevent the cord being cut by the corners of the post. Such a fixture, I am confident, would have held a five horse-power steam-engine from starting, with full pressure of steam on the piston, and no previous motion. Not so, however, with this engine, for the breaking of the cord and contact with the battery occurred at the same instant of time, leaving an impression in the beam to the depth of the cord, despite the protection of the sole-leather.' The engine continued to work in the most satisfactory manner; and Dr Page attached a circular-saw, which was used in wood, to a depth of six inches, and at a speed such as could be anticipated from the power which we afterwards found the engine to possess.
Careful experiments made to test the power of the engine, shewed it to be equal to seven horse nearly; and the estimate for consumption of acid and use of zinc is twenty cents for each horse-power per day of twenty-four hours. The escape of acid vapours from the batteries is an evil that will have to be guarded against, to prevent the pernicious effects produced in several electro-plating establishments, where the health of the workmen has been seriously injured by the liberated gases. This defect being overcome, Professor Page's electro-magnetic engine may become highly valuable in engineering and manufacturing processes. To quote the conclusions of the report—'the cost will be less than that of a steam-engine of the same power: the weight will be but one quarter, if boilers and contents be taken into account: the expense of firemen and engineers is dispensed with: buildings, and stocks of goods, and vessels may be more cheaply insured than when steam-engines are used, as there could be no risk from explosion or fire: the expenses are only active while the machine is positively in action, whereas an ordinary steam-engine continues its expenses whenever the fire is burning.
'Dr Page's engine, if used ten times during the day, of six minutes each time, would have but one hour's expenses for the day; whereas a steam-engine, under similar circumstances, would be subject to nearly or quite the full expenses of fuel for twenty-four hours, or equal to the expenses of continuous work.'