Fontenelle, of the Vfefulnefs 



Farther t a Geometrical Speculation, which 

 Was not at firft applicable to any ufe, becomes fo 

 afterwards. When the greateft Geometricians 

 in the Seventeenth Century fee about to ftudy a 

 new Curve, which they call'd a Gycloide, they 

 only engag'd themfelves in a meer Speculation 

 out of Vanity, Arriving to outdo one another by 

 the Difcovery of difficult Theorems. They did 

 nor even pretend that this was for the Publick 

 Good ; however by diving into the Nature of the 

 Cycloide it was found, that it was deftinM to 

 make Pendulums as perfect as may be, and carry 

 the Meafure of Time as far as it can go. 



It is the fame thing with Natural Philofbphy as 

 with Geometry. The Anatomy of Animals feems 

 infignificant ; and it only concerns us to know 

 that of Human Body. But yet fbme Parts of it, 

 which are of fb nice, or fb confus'd a Make, that 

 they are invifible, are fenfible and manifeft in the 

 Body of an Animal. Hence it is, that Monfters 

 themfelves are not to be negle&ed. The Me- 

 chanifm conceal'd in a particular Kind or in a 

 common Make, is unfolded in another kind, or in 

 an extraordinary Make ; and one wou'd be almoft 

 apt to fay,that Nature by multiplying and varying 

 fo much her Works, can't ibmetimcs forbear be- 

 traying her Secrets. All that the Antients knew 

 of the Load-ftone, was, that it attracts Iron. 

 But whether they did not value a Curiofity, which 

 promised them nothing ; or that their Genius did 

 not lead them to make Experiments, they have 

 not examin'd this Stone as carefully as they might. 

 One Experiment taught them, that it turns of its 

 felf towards the Poles of the World, and did put 

 into their Hands the ineftimable Trcafure of the 

 Mariners Compafs. They might eafily have 



