148 THE MICROSCOPE. 



His solar microscope he improved so as to permit of projection 

 of opaque objects. His death prevented the publication of his 

 methods, and his heirs never seemed disposed to give information 

 respecting this particular instrument. 



M. Alpinus used many endeavors to ascertain concerning the 

 construction of this instrument by Lieberkuhn, and while thus en- 

 gaged he became fascinated with the subject, and so he himself set 

 about improving Lieberkuhn's original designs. This he suc- 

 ceeded in, to the extent of perfecting to the form we now are using 

 the megascope. 



Euler, Teiher, and Martin each made some slight alteration in 

 the mechanism of the megascope (short account of an opaque solar 

 microscope, by Martin, in Graphical Perspective.) 



Again several years of obscurity follow in the history of our in- 

 strument. In 1770 Dr. Hill published a treatise in which he en- 

 deavored to explain the construction of timber by the microscope. 

 This revived the instrument. At same time, 1770, the elder Adams, 

 contrived an instrument for cutting sections of wood. This was 

 afterwards improved by Mr. Gumming. Dr. Hill and Mr. Custance 

 now endeavored to bring back the microscope to the old standard 

 and succeeded. Mr. Custance was unrivaled in his dexterity in pre- 

 paring, and accuracy in cutting thin transverse sections of wood. 



Up to this time, 1772, the highest magnifying glasses for micro- 

 scopes were made in Naples in 1765, by T Di Torre in globular 

 form. One of the four sent to the Royal Society was missing when 

 they were given to Dr. Baker for examination. The largest of these 

 left was -gig-" in diameter, and was said to magnify 640 x, the second 

 the size of i Paris point, or -^^\ and the third >^ Paris point or y^', 

 and magnified 2560 x. (See report in Phila. Transactions, vol. 56, 

 p. 67). With that which magnified the least, he was unable to see 

 any object with satisfaction and concludes his account by express- 

 ing a hope that he had not injured his eyesight and states that any- 

 one not used to microscopical investigation he fully believes would 

 have been blinded by the testing of them. 



In 1753 this same Dr. Baker writes that "the cumbersome and 

 inconvenient double microscope of Hooke and Marshal, were many 

 years ago reduced to a manageable size, improved in their structure, 

 supplied with an easy way of enlightening objects by a speculum 

 underneath and in many other ways rendered agreeable to the curi- 



