EARLY DAYS OF THE MICROSCOPE 



were never used for the purpose of studying minute 

 living objects. 



To Leonardo da Vinci belongs the honour of 

 seriously investigating, for the first time, the pro- 

 perties of concave and convex lenses, and several 

 alchemists, as the early chemists were called, used 

 flasks filled with water, concave mirrors or glass 

 balls to gather together the rays of the sun. " Long 

 before the dawn of the seventeenth century, the 

 principle of the lens was both comprehended and 

 applied to scientific matters by the Englishmen, 

 Leonard Digges and his son Thomas, and by the 

 Italian, Giambattista Porta." 



Towards the end of the sixteenth century and the 

 early part of the seventeenth century, interest in the 

 minute structure of natural objects appears to have 

 developed. As early as 1590, Thomas Mouffet used 

 magnifying glasses in studying small mites, and in 

 1637 Descartes invented a single lens microscope in 

 which the rays of light were reflected on to the object 

 by means of a concave mirror. This method of illu- 

 mination, it is interesting to note, is still used in 

 some forms of pocket magnifiers. Most of the early 

 discoveries were made v/itli single lenses, for in the 

 compound microscopes which were first made, it 

 was only possible to view such a small portion of an 

 object at one time that the advantage lay with the 

 less complicated instrument. 



The earliest microscopes were simply short tubes 

 of any material which would not admit light ; at one 

 end there was a lens, at the other a glass plate on 



18 



