John Bernoulli possessed perhaps the greatest genius of any bearing the name for pure mathematics and pure mechanics. He was a contemporary of such men as Leibnitz, Euler and Newton, a co-laborer with the two former, but never conceded the merits of Newton. He was of a peculiar disposition, of intense likes and dislikes and among his peculiarities it may be mentioned that he harbored an unreasonable hatred toward a worthy and deserving son. In 1742 he wrote a work entitled "Dissertation on Effervescence and Fermentation." To this work he added an appendix entitled "Concerning Artificial Perpetual Motion." The appendix translated into English and as published by Dircks, is as follows: Scarcely had I finished this dissertation, when, attentively considering the nature of precipitation and secretion, briefly explained in the last pages, there accidentally occurred to me a mode of constructing, by means of some continually flowing liquid, the much-talked of and long-desired Perpetual Artificial Motion; and this as a completion to my work, on account of the affinity of the subject, I now propose for the consideration of the learned. No one need be told how eagerly for a length of time this same Perpetual Motion has been sought after by the most celebrated men, how ardently desired; what indeed have they not contrived? To what expense have they not gone? How many machines have they not constructed? But all in vain. The secret desire of this Perpetual Motion still perplexes and torments many, and excites their minds to such a degree that we see the ears and minds of learned men carried away by it; yet many philosophers reject the idea, unanimously asserting that Perpetual Motion cannot be communicated and cannot be invented; which opinion is nevertheless not of any weight, seeing that they rashly judge that no one should be listened to who boasts of having found out such a thing; and their reasons (as I confess) do not suffice to convince me; for I do not hesitate to assert not only that Perpetual Motion may be discovered, but that it has now actually been discovered, as will be confessed by any one who reads these lines; and what is this labor to many? does not Nature herself (who is never said not to operate by mechanical laws) indicate Perpetual Motion to be possible? To recall but one instance, what is the constant flux and reflux of the rivers and seas but Perpetual Motion? Does it not all belong to Mechanics? Therefore, you must confess that it does not exceed the limits of mechanical laws, and is not impossible; what then hinders that following Nature in this, we should be able perfectly to imitate her? as indeed I shall so conclude, by declaring to these the possibility of Perpetual Motion and the manner of obtaining it; and lest thou come to an adverse conclusion, or regard it as a Titanic enterprise, I pray that thou mayest first well weigh the