THE MICROSCOPE. 



body, a triangular support was provided, on which the body 

 was readily turned. In order to make the light of a lamp, 

 or even day%ht, more efficient, this instrument was supplied 

 with a short tube, in which were two double convex lenses, 

 as in a magic lanthorn, which served to condense the light 

 upon the object. 



A work entitled Oculus Artificialis Tehdioptncvis, &c., 



was published at Nuremberg, in 

 1702, by Jean Zahn, in which 

 were contained numerous curious 

 aphorisms, and a description of 

 many compound microscopes, and 

 amongst others, two binocular 

 ones, and also a figure of the 

 microscope of Francis Grindelius, 

 represented by fig. 5. It will 

 be seen that this instrument was 

 used for opaque objects, and that 

 its optical part consisted of six 

 planoconvex lenses, but of its size 

 we have no record. 



About this period, 1696, we 

 find that Mr. Stephen Gray 

 of the Charterhouse {Philosophical Transactions, No. 221, 

 p. 280), suggests that globule lenses should be formed of 

 small pieces of glass melted into a globule on Charcoal by 

 means of a blow-pipe ; but finding that he could not always 

 succeed, and that on the side upon which they rested on the 

 charcoal they were more or less flattened or opaque, he was 

 led to the construction of his water microscope; this was 

 nothing more than a drop of that fluid lifted up with a pin 

 and deposited in a small hole in a piece of brass. The drop 

 retained nearly a spherical form, and showed objects with 

 some degree of distinctness. 



He subsequently contrived the apparatus represented by 

 fig. 6, to be used as a water microscope: a 5 is called the 

 frame of the microscope, and was made of brass one-sixteenth 

 of an inch thick ; at a is a small hole one-thirtieth of an inch in 



Fig. 5. 



