136 THE AMERICAN MONTHLY [June, 



years ago. The chief individual exhibitors in this department 

 were Dr. Van Heurck, of Antwerp, and A. Nachet, of Paris, 

 both of whose collections were large and attractive. 



Among the instruments most interesting for personal reasons 

 were three genuine microscopes of Leeuwenhoek (1673), which 

 had been used in his studies by that pioneer in histology, and 

 were exhibited here by an artist painter (P. A. Haaxman), of 

 Delft, a lineal descendant of Leeuweiihoek's sister; also an au- 

 thentic simple microscope of P. Lyonnet, accompanied with the 

 dissecting instruments he used with it in his famous study of cat- 

 erpillars, and I^y the numerous plates engraved by his own hand 

 (Maastricht, 1760), contributed by the Royal Zoological Societ}' 

 of Amsterdam ; a fine compound microscope presented to Buft'on 

 by his pupils (inscribed " a notre maitre pa?' ses eVcves ") in 

 1 75S, having a wooden base with three knobs to give a tripod 

 efiect, with a stout body, some 3 inches wide and 7 lo^ig? sup- 

 ported vertically by heavy brass-work and supplied with coarse 

 and fine adjustments; and a microscope by Amici, that formerly 

 belonged to the botanist Schleiden (1837). 



Of objectives, aside from the regular outfit of the various mi- 

 croscopes, there wereglobules from melted glass of 1750 and 1815 ; 

 lenses of garnet and of sapphire, by Charles Chevalier (1S35); 

 and an achromatic objective by Beeldsnvder, an amateur in Hol- 

 land just 100 years ago (1791). This objective, exhibited by 

 Dr. A. W . Hubrecht, professor of zoology in the University of 

 Utrecht, is claimed to be the first one made, and is so well con- 

 structed as to give a very good image. It consists of two convex 

 lenses of crown-glass, with a biconcave of flint between them, and 

 appears to be the earliest known adaptation of the achromatic tel- 

 escope object-glass to the microscope, which was revived unsuc- 

 cessfully at Modena bv Amici in 181 2, and successfully modi- 

 fied and introduced at Paris in 1823. 



A most interesting example of an ancient cabinet of slides was 

 a systematic collection of 300 preparations (i8th century), in 

 ivory slips, four specimens in a row in each ; the objects were 

 mounted in holes bored through the slips, they and their covers 

 being held in place by wire rings sprung into the cell and upon 

 the cover. Interesting preparations by Andrew Pritchard were 

 also shown (London. 1S25). 



Microscopes and Accessories. 



In this department the chief exhibitors were, naturally, the 

 manufacturers, and with only two notable exceptions they were 

 of the *•' continental" group. 



Among the whole it was evident that one, the Carl Zeiss es- 

 tablishment at Jena, was easily pre-eminent, on account of the 

 magnitude and variety of its exhibit, the high quality of its work, 

 and the extent and importance of its contributions to the recent 

 developement of the microscope, especially in inventing and in- 



