The Microscope. 229 



sequently corrected by collar for the same length of tube — thus 

 securing " equal rights " with each. 



The condition of field was next taken into consideration. 

 For this purpose a fine valve of Frustulia Saxonic was selected, 

 and so placed in the field (which was rendered of the same size 

 with each objective by the use of the proper eyepieces) that one 

 end was in the center while the other end was at the extreme 

 edge of the field. When thus arranged, the Zeiss showed the 

 lines distinctly as far as the central nodule while the Spencer 

 showed the lines all over the valve. 



Any attempt at a proper test by central light was rendered 

 extremely difficult from the short working distance of the 1-18. 

 I should liked to have used the mercury globule but gave it up 

 — relying entirely upon the two tests given as deciding the 

 merits of the lenses. 



I am sorry that I had neither Bausch & Lomb's nor Gund- 

 lach's objectives of similar power to try against the Zeiss, for I 

 am fully satisfied (from the reputation the Zeiss lenses have in 

 Europe) that the best objectives made anywhere are in the 

 United States. 



THAD S. UP DE GRAFF, M. D., F. R. M. S. 



C H. STOWELL. 



IT was never my good fortune to meet him whose death brings 

 sadness to so many hearts. But from correspondence only 

 one could readily understand why it was that Dr. Up de Graff 

 had so many warm friends. His generous nature was con- 

 stantly showing itself and "he had the rare faculty of making 

 his opponents at last his true friends." A life-long friend of 

 his promised our readers a sketch of his life, but was unable to 

 carry out his desires. So at the last moment, just as we go to 

 press, how can I, a stranger, speak in proper words when one of 

 his nearest friends has said that — '' of his generosity, of his de- 

 votion to his friends, of his sacrifices for others, of his grand 

 hospitality, of his delight in making others happy, of his versa- 

 tility in entertaining, of the thousand splendid traits of charac- 

 ter he possessed and which need not be rehearsed to those who 

 knew him ; of these I could not narrate the half had I unlimited 

 room and time. These are memories for us, his closest friends, 

 to cherish forever, and enjoy unto our dying day." 



