132 THE HISTORY AND DEVELOPMENT OF THE MICROSCOPE 



In H>7i! Sir Isaac Newton communicated to the Royal Society 



.I n ite and diagram tiir M reflecting microscope ; we have, however, 

 no evidence t hat it WMS ever c instructed. But in 1673 Leeuwen- 

 h<iek lie-Mil tn .send tuthe Royal Society his microsci >pical disci >veries. 

 Nothing WMS known of the n instruction of his instruments, except 

 that tliev were simple microscopes. even down to so late a period as 

 17"'.). We know. h<>\ve\er. that his microscopes were mechanically 

 rough. ami that optically they consisted of simple bi-convex lenses, 

 with worked .surface.-. mounted lietweeii two plates of thin metal 

 with minute apertures through which the objects were directly seen. 

 At his death Leeuwenhoek bequeathed a cabinet of twenty-six of his 

 microscopes t ithe Royal Society ; unhappily, they have mysteriously 



disappeared. But Mr. Mav 

 all was enabled to figure one 

 lodged in the museum of the 

 Utrecht University, which is 

 given in figs. 99 and 100 in 

 full size. The lens is seen in 

 the upper third of the plate. 

 It has a J-inch focus. The 

 object is held in front of the 

 lens, 011 the point of a short 

 rod, with screw arrange- 

 ments for adjusting the 

 object under the lens. 



Many modifications of 

 this and the preceding in- 

 struments are found with 

 some early English forms. 

 but no important construc- 

 tive or optical modification 

 immediately presents itself'. 

 hut some ingenious arrange- 

 ments are found in the 

 simple microscopes devised 

 by Musschenbroek in the 



FIG. 



Leeuwenhoek's micros,-,, ( (ic,;:;,. 



early years of the eighteenth 

 cent ury. 



figured a microscope in his ' Mierographia Nova' in 

 which optical modification, arise. Divinj had. as was 



'ombined two pla sonvex lenses, with theirconvex surfaces 



'"'"i an eye piece: this idea was carried further in l(i(>H 



111 optician, who used two pairs of these lenses; Grindl 



3 ! linl HI addition be used two similar (but smaller) lenses 



> manner as an objective. The form of the microscope 



'"'I ' from thai ofCherubin d'Orleans (fur. 97), but was 



f the application of an external screw. 



tonannus modified preceding arrangements by dovisinj; 

 bjecl between two plates pressed away from 



spiral spring, the focussing being then effected 

 barrel.' 



