X PREFACE. 



The zoologist finds in tlie Microscope a necessary co- 

 operator. To the geologist it reveals, among a multiplicity 

 of other facts, " that our large coal-beds are the ruins of a 

 gigantic vegetation ; and the vast limestone rocks, which 

 are so abundant on the earth's surface, are the catacombs 

 of myriads of animal tribes, too minute to be perceived by 

 the unaided vision." 



By " conducting the eye to the confines of the visible 

 form," the Microscope i3roves an effective auxiliary in 

 defining the geometric properties of bodies. Its influence 

 as an instrument of research upon the structure of bodies 

 has been compared to that of the galvanic battery, in the 

 hands of Davy, upon Chemistry. It detects the smallest 

 structural difference, heretofore inappreciable, and, as an 

 ally of Chemistry, enables us to discover the very small 

 changes of form and colour effected by test-fluids upon 

 solids ; and dissects for us, so to speak, the most multiplex 

 compounds. It opens out to the mind an extended and 

 vast tract, opulent in wonders, rich in beauties, and bound- 

 less in extent. 



The Microscope not only assists studies, and develops 

 objects of profound interest, but also opens up innumer- 

 able sources of entertainment and amusement, in the 

 ordinary conventional acceptation of these terms ; — dis- 

 closing to us peculiarities and attractions in abundance ; — 

 impressing us with the wonderful and beautifully-skilful 

 adaptation of all parts of creation, and filHng our minds 

 with additional reverence and admiration for the beneficent 

 and Almighty Creator. 



The Author will conclude these prefatory observations 

 with a few words in explanation of his arrangements, 

 and by way of acknowledgment to those to whom he is 

 indebted. He has sought, in the volume that he now lays 

 before the public, to point out and elucidate at once in a 



