TliE president's address. 307 



compare the productions of the present day — the apochromatics 

 both dry and immersion, of wide aperture, with the humbler pro- 

 ductions of the " sixties " and the " seventies," I do not despair of 

 seeing lenses in the near future as much superior to those of the 

 present day as our best modern lenses are superior to the most 

 perfect constructions of pre-apochromatic days. Even now, signs 

 of improvement are not wanting. Within the last few weeks I 

 have had an opportunity, through the courtesy of a member of 

 this Club, of examining a number of lenses, both achromatic 

 and apochromatic, by Mr. Reichert of Vienna, constructed on 

 an entirely new principle, and of glass which is guaranteed to 

 resist the effect of hot climates. These glasses, one and all, give 

 an image of great purity and brilliancy. They stand faii-ly deep 

 eyepiecing well, and have plenty of working distance, considering 

 their uniformly \\ide aperture. If Mr. Eeicherfc could be induced 

 to construct objectives of equally high merit for the long 250-mm. 

 tube, he would add not a little to his deservedly high reputation 

 as a constructor of first-class objectives. Messrs. Leitz, too, have 

 still further improved the series of lenses for which they have 

 recently become famous. They have devoted their attention to 

 the development to the highest attainable perfection of the 

 achromatic lens, using several permanent varieties of Jena glass, 

 but no fluorite, in their construction. 



Then again, these lenses are really marvels of cheapness. I 

 have recently selected a quarter-inch by this firm, possessing 

 an aperture of '77, which was scarcely distinguishable from an 

 apochromatic. I tested this glass in every possible way, com- 

 paring it with glasses which had cost four times as much, and I 

 was unable to detect in it any point of inferiority. The price 

 of this glass was only 255. 



But I trust I shall not be misunderstood if I express my 

 conviction that the cry for cheap objectives has been heard long 

 enough. For my own part — and I am not alone in this respect 

 — I should be glad to see opticians striving to excel one another, 

 not so much in the further cheapening of " popular" instruments 

 as in the construction of glasses of the highest possible excellence, 

 both in respect of resolving and of defining power. 



The experience of opticians both in this country and abroad 

 will show that microscopists do not grudge a reasonable price 

 for a really first-rate instrument. There will, of course, always 



