104 AN EMPIEICAL STUDY OF GYRATING BODIES. 



glass, as in fig. 20, resting on the point of the hooked 

 end, and having the axle inclined about 60°. 



N. B. If the point on the end of the gyroscope is 

 fine and sharp, and happens to be in line with the axis of 

 the shaft, the experiment will fail. The point should 

 be a little above the axis when held so that the latter is 

 horizontal. To this there is one very curious exception. 



If, instead of a point, the instrument ends in a small 

 knob or sphere, so placed that the axis produced passes 

 through its center (or near to it) the actual point of sup- 

 port will be below the axis line, and yet the instrument 

 may rise to a vertical. If the experiment be tried and 

 succeeds, it will be found that in a few moments the 

 ring and wheel whirl around together, as if they were 

 one piece, as it were, a top ; and, till this occurs, the 

 gyroscope will not rise. 



The explanation is curiously different from that of the 

 gyroscope proper. It belongs to the theory of the top ; 

 and, when that is understood, this will be found to pre- 

 sent no difficulty. 



THEORIES OF THE GYROSCOPE. 



A satisfactory explanation of the gyroscope must in- 

 clude not only all these phenomena, but any other that 

 it can be made to produce, and must make clear their 

 harmony with the long-known laws of motion. 



Many attempts have been made to give such an ex- 

 planation, but all — so far as I have seen them — more or 

 less unsatisfactory, and some quite absurd. 



It was my intention to precede my discussion by a 

 somewhat extensive examination of the various theories 

 heretofore advanced ; but I find that this would occupy 

 too much space, with little benefit other than to show the 

 need of more thorough study of the problem. 



I shall, however, sj3eak of a few erroneous ideas em- 

 bodied in certain theories which have become popular- 



88 



