EARLY DAYS OF THE MICROSCOPE 



ments, the minute pond animals he could see with 

 ease, and by 1683 he had even attained a sight of 

 the bacteria. His researches represented the high- 

 water mark of work done with the simple micro- 

 scope, most of the later work was carried out with 

 the compound instrument. 



The earliest history of the compound microscope 

 is difficult to separate from that of the telescope 

 and, in any complete account, the two instruments 

 must be considered together. It appears that the 

 first scientist that conceived the idea of using a 

 series of lenses, rather than a single lens, was 

 Leonard Digges, whom we have already mentioned. 



In a book by Porta, a writer who though not 

 himself original, was gifted with great curiosity and 

 industry in the collection of the ideas of others, 

 we read : '' How to make plain a letter held far 

 away by means of a lens of crystal," and also that 

 " with a concave lens you see things afar smaller 

 but plainer, with a convex lens you see them larger 

 but less distinct. If, however, you know how to 

 combine the two sorts properly you will see near 

 and far both large and clear." 



Shortly after the publication of Porta 's book the 

 method of combining two lenses into a microscope 

 or telescope was discovered, quite accidentally, by 

 a Dutch boy named Zacharias, who worked in the 

 shop of his father, a spectacle maker. The event 

 was described by Willem Boreel, Dutch Ambassador 

 to France, in a letter written in 1655. He wrote : 

 " I am a native of Middleburg, the capital of 



