Perpetual Motion 75 



" the second way whereby the making of a perpetual motion has 

 been attempted is by means of the magnetical virtues which are 

 not without some strong probabilities of proving effectual for this 

 purpose." He explains that Taisner, Peregrinus, Bettinus, 

 Cardan and others imagined that by a combination of loadstones 

 and steel, by alternate attractions and repulsions, such a motion 

 might be obtained, but thinks this cannot be, since " D. Gilbert, 

 who is especially versed in magnetical experiments, considers it 

 to be a vain and groundless fancy." He had himself tried several 

 methods, and at one time imagined himself crying, "Eureka!" 

 over a device which he describes. It essentially consisted of an 

 inclined plane with a small trapdoor opening from below at the 

 lower end, and a hole of certain size at the upper. At the top of 

 the plane was placed the loadstone or magnet, and a steel ball 

 was placed upon the plane. Of course it will, if the magnet be 

 sufficiently strong, run up the plane until it reaches the hole, 

 through which it will drop, and falling upon a track shaped to the 

 arc of a circle hung vertically, will run down the track, through 

 the trapdoor at the bottom, and start all over again. On further 

 consideration he sees it cannot succeed, and states his reasons 

 with considerable acuteness, but shows no sign of noticing that 

 anything but a mistake in method prevents the success. 



In 1 718 it was reported from Frankfort that there had there 

 been constructed an airship which operated most successfully. It 

 was raised by the power of a " Coral Agate " in its roof, a magnetic 

 action being thus produced. 



There have been very many inventions, and a host of schemes 

 for the utilization of magnetism for the i)roduction of power, but 

 in no case have I discovered anything novel or unrepresented by 

 the two or three instances I have already given. 



The number of inventions intended to utilize gravitation in 

 some form is beyond all expectation. . I have no doubt whatever 

 that a weighted wheel device was invented very early in the 

 history of the quest for perpetual motion, but the first historical 

 mention which I have noticed is found in the notebook of 

 de Honecourt, a French architect of the 13th century, whose 



