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field in Zeiss's eyepieces ; he thought this was a very great defect, 

 and it seemed as if whilst opticians had been striving to produce 

 perfection in the objectives and the stands, they had to a large 

 extent overlooked the need for perfection in eyepieces. 



Mr. J. D. Hardy asked if Mr. Nelson could tell him what was 

 the power of this eyepiece, and if was applicable to the telescope. . 



Mr. Nelson said the power was 12, but a higher power could 

 be made. The difficulty experienced in obtaining a large field 

 with good definition all over it was due partly to the objective, 

 which would not always stand it. Multiple eye-lenses used to be 

 common at one time, and there were some examples of these in 

 the Royal Microscopical Society's collection. A lens could always 

 be divided in that way, and by so doing the aberration was 

 reduced. He quite agreed that opticians had not given the 

 attention to eyepieces which they ought to have done. All the 

 compensating eyepieces were over- corrected so as to make up for 

 the under-correction of the apochromatic objectives. If, therefore, 

 a properly corrected objective was used with an over-corrected 

 eyepiece it ought to fail. Experience showed, however, that they 

 were not all alike, but both objectives and eyepieces had very 

 different amounts of under- and over- correction. 



The Secretary said that as their next ordinary meeting would 

 not be held until October, it was not worth while to give out 

 notices for three months, but he hoped new members would bear 

 in mind that the meetings would still continue to be held on the 

 usual evenings as " gossip nights." He hoped the members, who 

 would no doubt many of them be leaving home before they met 

 again in that room, would have a very pleasant vacation, and 

 that one result of their holiday excursions would be some more 

 papers for the Club. 



The proceedings then terminated with the usual Conversazione. 



