H 



MICROSCOPE AND ACCESSORIES 



\CH. I 



Length in Millimeters and Parts included in "Tube-Length" by 

 Various Opticians* 

 Pts. included 

 in "Tube- 'Tube-Length" in 



length." Millimeters. 



See Diagram. 



f E. Leitz, Wetzlar 170 mm. 



I Natchet et Fils, Paris 160 mm. 



j Powell and Lealand, London 254 mm. 



j C. Reichert, Vienna 160 to 180 mm. 



j Spencer Lens Co., Buffalo 160 mm. 



[W. Wales, New York 254 mm. 



f Bausch & Lomb Opt. Co., Rochester 160 or 216mm. 



I Bezu, Hausser et Cie, Paris 180 mm. 



I Klonne und Miiller, Berlin 160-180 or 254mm. 



-j W. & H. Seibert, Wetzlar 170 mm. 



j Swift & Son, London 165 to 228^ mm. 



I C. Zeiss, Jena 160 or 250 mm. 



[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 i6oandi8omm. 



Verick (Stiassnie) Paris 160-200 mm. 



Watson & Sons, London 160-250 mm. 



J. Zentmayer, Philadelphia 160-235 mm. 



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



Various Opticians. 

 j Powell and Lealand, London, 

 roo mm. \ w. Wales, New York. 



r 2 5 °g- mm. Watson & Sons, London. 



T - J E. Leitz, Wetzlar. 



1 o'o mm. j r, Winkel, Gottingen, Germany. 



'-XTrf- mm. Ross & Co., London. 



f Klonne und Miiller, Berlin. 

 18 j Spencer Lens Co., Buffalo. 



roo mm. 1 Bausch & Lomb Optical Co., Rochester. 



[Queen & Co., Philadelphia, 

 mm. C. Zeiss, Jena, 

 mm. C. Reichert, Vienna. 



(Gundlach Optical Co., Rochester. 

 W. and H. Seibert, Wetzlar. 

 R. and J. Beck, London, 

 mm. J. Zentmayer, Philadelphia. 

 j Nachet et Fils, Paris. 

 \ Bezu, Hausser et Cie, Paris. 

 Swift and Son, London. 

 E. Hartnack, Potsdam, German)'. 



"10" (i 



-5.-1 i 



"1 IT 



l_0J_'l 5. mm 



r V o mm. 

 -? oh- mm. 



*The information contained in these tables was very kindty 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 

 (3 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. 168, 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 being 



