To produce the motion, draw the plug from the orifice _a_, from which the water gushing out with considerable force will immediately turn the water-wheel, which communicating motion, by the crank _d_ and rod _e_, to the beam E, will cause the pump D to be worked, the water from the spout passing into the upper vessel A. Now, the cylinder of the pump, if one only be used, must be of suitable dimensions, or the velocity of its movement so increased by means of a multiplying-wheel as to enable it to discharge water into the upper vessel A faster than the same escapes through the lower orifice _a_; consequently, the vessel A will soon overflow from the capacious opening at _b_, to which a trough is attached, which collecting the waste water, causes it to descend also upon the circumference of the water-wheel; thus contributing to its movement, and at the same time tending to preserve an uniform supply of water in the reservoir for the continued action of the pump. Hence you have a perpetual motion, so long as the whole keeps in repair and in good order, which is all that can be expected of any perpetual motion, constructed as it must be of perishable materials. But of what use are all the perpetual motion machines, if they can perform no other work than that of keeping themselves in motion? For it is evident, in the case of my machine, that if I wish to increase the power of the wheel, fixed as it is in size, radius, etc., I must increase the jet of water, and consequently the pumps must be made of corresponding dimensions, or exert a corresponding increase of force or velocity to replace the water; so that it is evident, neither Mr. Linley's machine nor mine, in their present fixed state, can perform more than the simple operation of pumping their own water. And this is the case with all the perpetual motion machines I have ever observed--they can exert no useful or disposable power beyond that of keeping up an equilibrium, or getting beyond the point of equilibrium. Yours, etc., AUTHOR OF THE "VOICE OF REASON." An Italian Device In 1825 there was published in London in Mechanics' Magazine the account of a very ancient invention by an Italian. He had written an account of his invention in Latin. It had been translated and furnished to Mechanics' Magazine by a correspondent of that Magazine. The communication so furnished as published is as follows: The underwritten is translated from an ancient Latin book * * * (entitled "De Simia Naturæ," Autore Roberto Fludd), which treats of every science known at the time it was published, and largely of the science of mechanics. What followed I have extracted merely to show that the discovery of the perpetual motion was as nearly attained then, perhaps, as it is now.--I am, &c., P.