16 HISTORY OF 



an Italian mathematician, also expressly informs us, in his Life of 

 Galileo, that this great man was led to the construction of the micro- 

 scope from that of the telescope ; and in the year 1612 he actually 

 sent a microscope to Sigismund, King of Poland. In the year 1618, 

 Fontana, a Neapolitan, made a microscope of two double convex 

 lenses, and wrote an account of it in a work which he published 

 in 1646. 



For a long period, however, curious as the fact may now appear, 

 the single microscope was that generally in use, and the compound 

 instrument was considered as a mere philosophical toy, owing to the 

 distance which the light had to traverse, and the consequent increase 

 of the chromatic and spherical aberrations. Indeed so impossible did it 

 appear to overcome this great difficulty, that within thirty years of the 

 present period, philosophers of no less eminence than M. Biot and Dr. 

 Wollaston predicted, that the compound would never rival the simple 

 microscope, and that the idea of rendering its object-glass achromatic 

 was hopeless. Nor can these opinions be wondered at, when we con- 

 sider how many years the achromatic telescope had existed without any 

 attempt to apply its principles to the compound microscope. When 

 we consider the smallness of the pencil required by the microscope, and 

 the enormous increase of difficulty attending every enlargement of the 

 pencil ; when we consider further, that these difficulties had to be con- 

 tended with, and removed, by operations on portions of glass so small 

 that they were themselves almost microscopic objects, we shall not be 

 surprised, that even a cautious philosopher and able manipulator, like 

 Dr. Wollaston, should prescribe limits to its improvement. 



4. Fortunately, however, for science, and especially for the de- 

 partments of animal and vegetable physiology, these predictions have 

 been shown to be unfounded. The last fifteen years have sufficed to 

 elevate the compound microscope from the condition we have described, 

 to that of being the most important instrument ever bestowed by art 

 upon the investigator of nature. It now holds a very high rank 

 amongst philosophical instruments; while the transcendent beauties of 

 form, colour, and organization which it reveals to us, in the minute works 

 of nature, render it subservient to the most delightful and instructive 

 pursuits. To these claims on our attention it appears likely to add a 



