Report on the Lister Legacy. By E. J. Spitta. 149 



mind the effects of coma and of astigmatism, although of course no 

 mention of such names is to be found in his papers. ,"3 



In addition, are several different sets of holes in brass plates, 

 carefully wrapped in paper coverings ; one set having a wrapper on 

 which is furnished the size of each of the holes. These holes were 

 used in the experiments to ascertain the effects of not completely 

 filling the pupil of the eye, and showed an advance of thought in 

 this wonderful man that distinctly placed him in advance of all in 

 his time. 



More interesting relics of Lister's experiments are to be found 

 in a collection of several black and white rulings, the lines being 

 about xV'i^^- ^^ thickness. Some of these were crossed to make 

 cheques (called chequers in the experiments), and there were 

 additional sets made with much thinner lines. An arrangement 

 was also found that enabled the experimenter to set his cross lines 

 at any angle that might be desired. 



The first of the micrometers is made in brass, and is of unique 

 design. It is constructed to measure objects of sensible dimensions, 

 and yet others that are extremely small, by the adjustment of a 

 curiously constructed guide-screw. The remaining micrometers 

 are all of the stage variety, and are to be found in little boxes, but 

 up to the present no evaluation of the rulings has been made. 



A pair of very long and thin Nicol's prisms, some rather fine 

 selenites, two adapters for objectives ''for the Eoss and Powell 

 Microscopes," complete the collection of optical apparatus here 

 reported upon. 



