A HISTORY OF SCIENCE 



Many opticians, indeed, quite despaired of ever being 

 able to make a satisfactory refracting compound micro- 

 scope, and some of them had taken up anew Sir Isaac 

 Newton's suggestion in reference to a reflecting micro- 

 scope. In particular, Professor Giovanni Battista 

 Amici, a very famous mathematician and practical 

 optician of Modena, succeeded in constructing a re- 

 flecting microscope which was said to be superior to 

 any compound microscope of the time, though the 

 events of the ensuing years were destined to rob it of 

 all but historical value. For there were others, fortu- 

 nately, who did not despair of the possibilities of the 

 refracting microscope, and their efforts were destined 

 before long to be crowned with a degree of success not 

 even dreamed of by any preceding generation. 



The man to whom chief credit is due for directing 

 those final steps that made the compound microscope a 

 practical implement instead of a scientific toy was the 

 English amateur optician Joseph Jackson Lister. Com- 

 bining mathematical knowledge with mechanical in- 

 genuity, and having the practical aid of the celebrated 

 optician Tulley, he devised formulae for the combina- 

 tion of lenses of crown glass with others of flint glass, so 

 adjusted that the refractive errors of one were corrected 

 or compensated by the other, with the result of produc- 

 ing lenses of hitherto unequalled powers of definition ; 

 lenses capable of showing an image highly magnified, 

 yet relatively free from those distortions and fringes of 

 color that had heretofore been so disastrous to true in- 

 terpretation of magnified structures. 



Lister had begun his studies of the lens in 1824, 

 but it was not until 1830 that he contributed to the 



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