14 ' INTKODUCTOKY ADDRESS: 



In the Bibliography accompanying the present Address will be 

 found reference to some of the writings of other early workers with 

 the Microscope. For example, Antony van Leeuwenhoek, born at Delft 

 in 1632, constructed the first practical microscope and established the 

 art of properly grinding and polishing the Lenses. 



Leeuwenhoek w^as offered, and accepted, the post of Chamberlain 

 of the Sheriff of the town of Delft, worth £26 annually, and held this 

 for 39 years. Li February, 1680, he was made a Fellow of the Eoyal 

 Society. Although he never came to London, the Diploma of Fellowship 

 was sent to him in a silver box, having the Arms of the Society graven 

 on it. An interesting account of his life is given by the President of the 

 Royal Microscopical Society, Professor H. G. Plimmer, F.R.S., in his 

 Presidential Address in 1913. 



Leeuwenhoek did wonderful work with his simple or singular 

 Microscope. The largest magnification he obtained was about 160 

 in one of his Microscopes : his twenty-six other Microscopes varied 

 from 40 to 133 magnifications. With this simple instrument, as 

 Professor Plimmer points out in his address, Leeuwenhoek discovered 

 a new world, in fact new w^orlds, for us. He saw for the first time 

 Infusoria, Rotifers, and Bacteria. It is interesting to note in this 

 connection that Charles Darwin took no compound Microscope, but 

 only a simple one, with him on his famous " Beagle " Voyage. 



So important was Leeuwenhoek's w^ork that I give a portrait of 

 him (Fig. 8). 



In the paper " On the Construction of the Compound Achromatic 

 Microscope " by Charles Brooke, M.A., F.R.S., read before the 

 Royal Institution of Great Britain, March 10th, 1854, he states 

 that the first compound Microscopes^ on record, such as that of 

 P. Bonnani, about 1697, which was placed horizontally, and that of 

 J. Marshall in the beginning of the eighteenth century, which was 

 vertical, were furnished with central condensers. In later years the 

 development of the illuminating apparatus has by no means kept pace 

 w^ith that of the ocular portion of the Microscope, though scarcely of 

 less importance in attaining the highest perfection in the vision of 

 microscopic objects. 



On the authority of Adams, the first three compound Microscopes 

 were said to be those of Hooke, Eustachio Divinis and Phili]^ 

 Bonnani. An account of Divinis' Compound Microscope was read 

 before the Royal Society in 1668 (Philosophical Transactions No, 42). 



It must be borne in mind, too, that the progress made in the science 

 of Optics was largely aided by the great work of Sir Isaac Newton, 

 Delavel and Herschel. 



1700 TO 1800 A.D. 



It is stated by Roberts-Austen also in his *' Metallurgy " that the 

 Microscope was first apj^lied to the Examination of L'on and the 

 first records go back to 1722 when Reaumur described the structure 

 of Chilled Castings under the Microscope. Franyois in 1832 took 



