Identifier: reporttransactio73glas (find matches)
Title: Report and Transactions of the Glasgow Society of Field Naturalists
Year: 1879 (1870s)
Authors: Glasgow Society of Field Naturalists
Subjects:
Publisher: Glasgow: Glasgow Society of Field Naturalists
Contributing Library: Natural History Museum Library, London
Digitizing Sponsor: Natural History Museum Library, London

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^^AL H\^ GLASGOW SOCIETY OF FIELD NATURALISTS. 127 The magnified image produced by the rays of light after havingpassed the object-glass and crossed in the focus of the backcombination, are viewed by a simple microscope at the upper endof the body called the Eye-piece. The Huyghenian eye-piece (fig. 10), commonly used, consists oftwo plano-convex lenses with their convex sides directed towardsthe object-glass. The lower larger one is called the field-glass, theupper one the eye-glass. These eye-pieces give a field of from 4to 6 inches diameter. The Huyghenian eye-piece is not achromatic,being under corrected for colour, and to secure achromatism of themicroscope ail good object-glasses are so constructed that they areover corrected for colour. The Kellner or orthoscopic eye-piece (fig. 11) has a double convexlens placed in the focus of the achromatic eye-glass without theinterposition of a diapliragm. It does not give quite as gooddefinition as the ordinary eye-piece, but it yields a

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