14 



MICROSCOPE AND ACCESSORIES 



\CH. I 



Length in Millimeters and Paris included in 

 Various Opticians* 

 Pts 



'Tube-Length" by 



* C3 



Tube-Length" 



Millimeters. 



Fir,. 24. 

 Thickness of 



i',r mm. 

 vP mm. 



'-Mi 8 mm. 



- : hf- mm. 

 ] -r o's- mm. 



rtfV mm. 



- r iu-}j- mm. 



ucluded 

 'Tube- 

 length." 

 See Diagram. 



I' E. Leitz, Wetzlar 17° mm. 



I Natchetet Fils, Paris 160 mm. 



Powell and Lealand, London 254 mm. 



C. Reichert, Vienna 160 to 1S0 mm. 



Spencer Lens Co., Buffalo 160 mm. 



W. Wales, New York 254 mm. 



f Bausch & LombOpt. Co., Rochester. __ 160 or 216mm. 



I Bezu, Hausser et Cie, Paris 1S0 mm. 



I Klonne und Miiller, Berlin 160-1S0 or 254mm. 



-! \V. & H. Seibert, Wetzlar 170 mm. 



Swift & Son, London 165 to 22S 1 , mm. 



I C. Zeiss, Jena 160 or 250 mm. 



I R. Winkel, Gottingen 192 mm. 



. Gundlach Optical Co., Rochester 254 mm. 



. Ross & Co., London 254 or 160 mm. 



. Queen & Co., Philadelphia 160 mm. 



. R. & J. Beck, London 254 or 160 mm. 



. Hartnack, Potsdam, Germany i6oand iSomm. 



Verick (Stiassnie) Paris 160-200 mm. 



Watson & Sons, London 160-250 mm. 



J. Zentmayer, Philadelphia 160-235 mm. 



Cover-Glass for Which Non-Adjustable Objectives are Corrected by 



Various Opticians, 

 f Powell and Lealand, London, 

 i W. Wales, New York. 



Watson & Sons, London. 

 I E. Leitz, Wetzlar. 

 I. R. Winkel, Gottingen, Germany. 



Ross & Co., London. 

 C Klonne und Miiller, Berlin. 

 I Spencer Lens Co., Buffalo. 

 I Bausch & Lomb Optical Co., Rochester. 

 I Queen & Co., Philadelphia. 

 C. Zeiss, Jena. 

 C. Reichert, Vienna. 

 ( Gundlach Optical Co., Rochester. 



W. and H. Seibert, Wetzlar. 

 |_R. and J. Beck, London. 



J. Zentmayer, Philadelphia. 

 I Nachet et Fils, Paris. 

 [ Bezu, Hausser et Cie, Paris. 

 Swift and Son, London. 

 E. Hartnack, Potsdam, Germany, 



*The information contained in these tables was very kindly furnished by the 

 opticians named, or obtained by consulting catalogs. In most of the later catalogs 

 the information is definite, and many makers now not only put their names and the 

 equivalent focal length on their objectives, but they add the numerical aperture 

 ( 'i 31 ) and the tube-length for which the objective is corrected. This is in accord- 

 ance with the recommendations of the author in the original paper on "tube- 

 length," (Proc. Amer. Soc. Micr., Vol. IX., p. 16S, also by Bausch, Vol. XII, p. 

 43). If the table in this edition is compared with the original table or with that in 

 the previous edition of this book some differences will be noted, the changes beintr 



