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CHAPTER VI. 



A description of the Achromatic Microscope, together with 

 its Apparatus and the mode of using it. 



IN a country like England, preeminently distinguished 

 for mechanical inventions, it would be strange, indeed, 

 if the constructing of stands for microscopes, their 

 mountings, apparatus, &c. had not attracted the atten- 

 tion of some of her artists. Since the publication of the 

 first edition of this work, numerous contrivances of a 

 highly ingenious description have been devised for their 

 improvement ; and though many of them are too complex 

 ever to become of general utility, yet are they such on 

 the whole as have tended to advance this instrument to 

 its present effective condition. Several artists in France 

 and Germany have also especially directed their thoughts 

 to the microscope, and have produced some which, as 

 specimens of workmanship, claim, no doubt, very con- 

 siderable merit ; but they do not appear to have had 

 sufficiently in view the principles upon which they ought 

 to be constructed. Those which have fallen under my 

 notice are wholly unsuited for general purposes of ob- 

 servation a circumstance which is the more surprising, 

 because there being exhibited so much talent in the op- 



