Another demonstrator of the impossibility of perpetual motion, is Mr. Mackinnon (see "Mechanical Magazine," Vol. 1, Page 363). As no doubt the different attempts to produce, or communicate, continued and perpetual motion, at least, such as are often brought forward by persons unacquainted with the science of mechanics, are generally to those who are acquainted with that science, if not absolutely ridiculous, yet of a nature to excite a smile at their futility: still there are a few (perhaps a very few) who entertain an opinion that such a thing is not impracticable, and who have, from practical experience as well as study, acquired a tolerable insight into the laws of nature (so far as relate to this subject); who in their turn cannot help smiling at the weak reasoning of some other would-be philosophers, who gravely give their dictum in the case. In this class I include Mr. Mackinnon, who very gravely goes to work to prove, etc., and flatters himself he shall, if rightly understood, help to prevent much future waste of time on the subject. He then goes on to give us his definition of inertia, by which he informs us that a body in a state of rest will remain so until it is moved (wonderful!)--that it cannot move itself--that it has not that power--and that no mechanical contrivance can give it that power. (How profound!) SUMMARIZED TABLE OF CONTENTS Page Introduction 3 Contents 5-6 Preface 7-10 Introductory Essay 11-21 CHAPTER I--DEVICES BY MEANS OF WHEELS AND WEIGHTS-- Wilars De Honecort; A Repetition of Wilars Honecort's plan; Leonardo da Vinci; A. Capra's Device; The Device of Dixon Vallance; Furman's Device; Schirrmeister's "Mechanical Movement;" James Ferguson's Device; B. Belidor's Device; Desagulier's Proposition on the Balance; John Haywood's Device; Explanation of the Failure of Wheels and Weights Devices to Accomplish Perpetual Motion 22-67 CHAPTER II--DEVICES BY MEANS OF ROLLING WEIGHTS AND INCLINED PLANES-- Device by Mercury in Inclined Glass Tube and Heavy Ball on Inclined Plane; Series of Inclined Planes; Devices by Oscillating Trough and Cannon Balls; Unpublished Inclined Plane and Weights Devices Noted by the Author 68-75 CHAPTER III--HYDRAULIC AND HYDRO-MECHANICAL DEVICES--