Olituary. 409 



objectives beyond a certain point ; and shows how the most likely- 

 direction of progress lay in the direction of photography by means 

 of light of shorter wave-length than that employed in visual 

 observations. 



Another paper of his, published in 1897, deals with the 

 Greenough Binocular Microscope.* It gives a concise account of 

 the theory of stereoscopic vision as applied in that instrument. 



Of microscopical appliances which bear his name may be men- 

 tioned the Corneal Microscope ; and the special Axial Image 

 Eye -piece with Iris diaphragm, for studying the rings and brushes 

 of crystals. 



Dr. Czapski's last paper was one of a popular character relating 

 to the various applications of Photography in Scientific Eesearch.f 

 Photography was a subject in which he had always taken a keen 

 interest, and he was an Honorary Fellow of the Royal Photographic 

 Society. He became a Fellow of the Eoyal Microscopical Society 

 in 1897, and on several occasions attended the meetings. 



Amongst the numerous German societies to which he belonged 

 may be mentioned the Deutsche Gesellschaft fiir Mechanik und 

 Optik, of which he was Vice-President. 



He, with others, was responsible for the editing of Abbe's 

 Collected Papers. J He aided in conducting the Zeitschrift fiir 

 Instrumentenkunde, and at one time was a frequent contributor to 

 its pages. 



His valuable services in the cause of science were recognised by 

 the conferment of the title of Professor by the Prussian Ministry. 



All who knew Dr. Czapski testify to the winning manners and 

 charming personality of the man. He possessed in a peculiar 

 degree the gift of influencing and inspiring the many classes of 

 people with whom he came in touch ; it was a characteristic which 

 aided him largely in the prosecution of his plans, besides securing 

 him a wide circle of friends. 



He married at an early age, and leaves a large family. Though 

 his health had for many years not been of the best, his sudden and 

 early death came completely unexpectedly, and will be deplored 

 throughout the world by all interested in the progress of optical 

 science and industry. 



Along with Abbe — the great man to the furtherance of whose 

 work he so unselfishly and assiduously devoted himself — will ever 

 be associated his friend Czapski, who outlived him little more than 

 two years. 



* " Das stereoskopische Mikroskop nach Greenougli." Zeitschr. wiss. Mikrosk. 

 Xiv. (1897) pp. 289-303. 



t " Der Wert der Photographie fiir die vvisseuschaftliche Forschung." Photo- 

 graph. Corresp., Dec. 1906 and Jan. 1907. 



X " Gesammelte Abhandlungen von Ernst Abbe," published in 1904-6, by 

 ■ Gustav Fischer, Jena, of which three volumes have so far appeared. 



Aug. 21st, 1907 2 E 



