4 HISTORY OF THE MICROSCOPE. 



one person having made the same invention nearly simul- 

 taneously, without any communication from one to the 

 other. In 1685 Stelluti published a description of the 

 parts of a bee, which he had examined with a microscope. 



The history of the microscope, like that of nations and 

 arts, has had its brilliant periods, in which it shone with 

 uncommon splendour, and was cultivated with extraordi- 

 nary ardour ; and these have been succeeded by intervals 

 marked with no discovery, and in which the science seemed 

 to fade away, or at least to lie dormant, till some favour- 

 able circumstance the discovery of a new object, or some 

 new improvement in the instruments of observation 

 awakened the attention of the curious, and reanimated 

 their researches. Thus, soon after the invention of the 

 microscope, the field it presented to observation was culti- 

 vated by men of the first rank in science, who enriched 

 almost every branch of natural history by the discoveries 

 they made by means of this instrument. 



The Single, or Simple Microscope. We shall first speak of 

 the single microscope, that having been invented and used 

 long before the double or compound microscope. When 

 the lenses of the single microscope are very convex, and 

 consequently the magnifying power great, the field of view 

 is small ; and it is so difficult to adjust with accuracy their 

 focal distance, that it requires some practice to render the 

 use of them familiar. It was with an instrument of this 

 kind that Leeuwenhoek and Swammerdam, Lyonet and 

 Ellis, examined the invisible forms of nature, and by their 

 example stimulated others to the same pursuit. 



About the year 1665, small glass globules began to be 

 occasionally applied to the single microscope, instead of 

 convex lenses ; and by these globules an immense magni- 

 fying power was obtained. Their invention has been 

 generally attributed to M. Hartsoeker ; though it appears 

 that we are really indebted to the celebrated Dr. Hooke 

 for this discovery, for he described the manner of making 

 them in the preface to his Micrographia Illustrata, pub- 

 lished in the year 1656. 



Mr. Stephen Gray 1 having observed some irregular 

 particles within a glass globule, and finding that they 



(1) Philosophical Transactions, 1696. 



