I. MICROSCOPES. 901 



The microscopes exhibited are the oldest iii the collection of the Cassel 

 Museum. 



The microscope of Jan van Musschenbroek dates from the 17th century. 

 It has been frequently described and represented in drawings. The University 

 of Le}*den possesses a similar one. This specimen was seen in 1709 by 

 Uffenbach in the collection of Professor Wolfarth in Cassel. 



3529. Two Microscopes, by Leutmann, in leather case. 



Royal Museum, Cassel (Director, Dr. Pi?ide?*}. 



These are microscopes by (or after) Leutmann, as is shown by the 

 drawing in Wolff's " Allerhaud Niitzliche Versuche," III. Bd., p. 291. 

 Harting gives no drawing of these microscopes. 



3530. Microscope, by Hartsoeker, in leather case. 



Royal Museum, Cassel (Director, Dr. Pinder). 



This microscope by Hartsoeker was invented before 1694. Wolff, who 

 gives a description and drawing of it, makes no mention of Hartsoeker as 

 being its inventor. It was found by Uffenbach in Professor Wolfartk'a 

 collection. 



3531. Microscope, by Campani, in leather case. 



Royal Museum, Cassel (Director, Dr. Finder). 



One of the microscopes by Campani, which Landgrave Charles bought in 

 Rome. 



Catadioptric Microscope of Axnici. 



The Royal Institute of " Studii Superiorly Florence. 



Dioptric Micro'scope of Amici. 



The Royal Institute of " Studii Superiorly Florence. 



One of the two microscopes has, instead of an object-glass, a concave mirror 

 exquisitely worked in metal ; the greater enlargements are obtained by varying 

 the ocular ; the other has its stage (porta oggetti) rendered movable by means 

 of two very delicate micrometrical screws, so that, in this way, it can also be 

 used as a micrometer. Both are for horizontal vision ; in the first instrument, 

 the image of the object being reflected by a plane metallic reflector ; in the 

 second one, by a rectangular prism. Particular attention is due to the 

 camera lucida which accompanies them, and to the various systems of illu- 

 mination. Among the instruments of Amici existing in Florence is his great 

 refractor, more than five meters in length, with an objective 29 centimeters in 

 diameter, an excellent instrument. It could not be sent for exhibition on 

 account of its size. 



3526a. Microscope of Nobili. 



The Royal Institute of" Studii Superiorly Florence. 



3530a. Microscope of Amici. 



The Royal Institute of " Studii Superiori," Florence. 



3517. Grand Microscope, with solar reflector and appli- 

 ances. Made by Benjamin Martin about 1740. 



The Committee, Royal Museum, Peel Park, Salford. 



