PETER PEREGRINUS. 169 



After stating that he proposes to describe the occult 

 nature of the lodestone in simple language, Peregrinus 

 lays down the principles of experimental research. While 

 he admits the value of general reasoning, he warns the 

 reader against relying upon speculation and theory alone. 



In the abstract, he says, many things appear true and cor- 

 rect which cannot be done by hands. The student must 

 exhibit the wonderful effects by his work ; for, by actually 

 doing things, he can remedy errors which he never can cor- 

 rect by mathematics. This may seem curious counsel from 

 the inventor of a perpetual motion, and lead to the query 

 whether he practiced what he himself preached. The an- 

 swer is suggested further on, when Peregrinus describes 

 the first of his self-moving contrivances. If it does not 

 work, that fact, he says, is to be ascribed to the lack of 

 mechanical skill in the maker, rather than to inherent 

 difficulties of the mechanism. This, of course, is one way 

 of avoiding a troublesome issue ; but it must be remem- 

 bered that Peregrinus is writing from the seat of war, 

 where he probably has had no means of obtaining accurate 

 workmanship. He is sure of the conclusions which he 

 has deduced from experiment ; and, having tested some 

 probably rude form of his machine and finding that it re- 

 fuses to work, he considers this due, not to erroneous 

 deductions, but to imperfections in the making. Hence 

 this warning at the outset. 



He next tells how to select a good magnet. In color 

 it must be iron-like slightly bluish and pale. The best 

 comes from the northern regions, and is used by sailors 

 who travel between the ports of the northern seas, notably 

 those of Normandy and Flanders. This preference for the 

 northern magnet is noteworthy, not only as showing that 

 the best lodestone existed in the part of Europe where the 

 compass found its first employment, but also because it 

 is in direct variance with all the earlier writers who in- 

 variably give first place to the Indian stone. The heavier 

 and more compact the magnet, the better, although such 





