Early Histoi'y of the Microscope. 9 



rest, and nothing of importance was done till 1770, when 

 Dr. Hill published a treatise on the structure of timber. So 

 important a subject revived the ardour for microscopic pursuits, 

 and we find about this time the elder Adams contrived a micro- 

 tome for cutting transverse sections of wood, which instrument 

 was improved by a Mr. Gumming, and also later on by the 

 younger Adams. 



In 1771 the elder Adams pubhshed a fourth edition of his 

 ♦ Micrographia,' in which, amongst other appliances then in use, 

 he describes a contrivance of his own for applying the solar 

 microscope to the camera obscura, and illummating it at night 

 by a lamp, by which means a picture of microscopic objects 

 might, he says, be exhibited on winter evenings, and also the 

 variable microscope. 



It seems that Lieberkuhn had adapted his solar microscope 

 for viewing opaque objects ; but the contrivance was lost. 

 Knowing, however, that this had been done, a certain M. ^pinus 

 turned his attention to the subject, and in some measure suc- 

 ceeded ; but his success seems to have been marred by employing 

 a too small illuminating mirror. Some further improvements 

 were made by M. Ziehr. But the most perfect instrument of 

 the kind was that described by Mr. Benjamin Martin in 1774. 

 In 1777 we have Dellebarre's microscope, and in 1784 M. iEpinus 

 describes some newly invented microscopes in a letter to the 

 Academic des Sciences of St. Petersburg, about which the 

 younger Adams makes some rude remarks as to their being 

 simply the application of the achromatic perspective, long known 

 in regard to telescopes, to microscopic purposes. 



This, gentlemen, brings us to what we may call the end of the 

 history of the microscope in the unachromatised state, and 

 I think that when we look at the wonderful and good useful 

 work done by our forefathers, and compare the instruments at 

 their command with our present day microscopes, we cannot 

 but admire their courageous researches, and reverence their 

 memory as the founders of a science which has had, and is 

 having, not only an interest for those wishing to see Nature in 

 detail, but has enabled us to discover much which has been a 

 real benefit to the health and life of man. 



