iv PURSUIT OF KNOWLEDGE 69 



account there are many insect-hunters and collectors, 

 but few who have an intimate acquaintance with the 

 habits of insects in the life. 



One such open-eyed naturalist was Reaumur, born at 

 La Rochelle in 1683, and as diligent and accurate an 

 observer as ever lived. Reaumur's History of Insects 

 occupies six large volumes, and though issued so long 

 ago as between 1734 and 1742 they are still a rich mine 

 of information upon all aspects of insect-life observable 

 with the naked eye or a simple lens. Referring to his 

 accounts of the change from a caterpillar into a chrysalis, 

 and of the chrysalis into a moth, Prof. L. C. Miall says : 

 " These luminous descriptions are now reproduced with 

 cruel abridgment in all popular works which treat of 

 insect-transformations . . . The only important additions 

 which naturalists have made to Reaumur's account 

 of the transformations of Lepidoptera relate to the 

 internal changes, and these demand a minute acquaint- 

 ance with insect anatomy." 



The geometrical or mechanical properties of Nature 

 are far more easily defined with precision than are any 

 of the processes of organic life. Five hundred years 

 before the commencement of the Christian era, Pytha- 

 goras observed that the three angles of every plane 

 triangle together make up two right-angles ; and this 

 conclusion stands now as it did then. Two and a half 

 centuries later Archimedes proved that an object 

 immersed in a fluid is buoyed up with a force equal to 

 the weight of the fluid displaced ; and this principle 

 admits of no alteration whether it is applied to the 

 flotation of a ship in water or the buoyancy of a balloon 

 in air. Hipparchus, the founder of astronomical science, 

 who lived in the second century B.C., determined the 

 periods of revolutions of the planets with remarkable 



