British Standard Graticule

Fig. 3.2 The British Standard Graticule (Graticules Ltd) [11], Diagram from BS 3406 (1963), Confirmed April 1993 Methods for the Determination of the Particle Size of Powders-. Part 4, Optical Microscope Method. (Reproduced by permission from British Standards Institution, 2 Park Street, London Wl, from whom copies of the complete standard may be obtained.)...

Cawood where the series is much closer. He also described a graticule, having nine circles in a V2 progression of sizes, for use with the projection microscope [71]. This was incorporated in a projection screen instead of being in the eyepiece and was adopted by the British Standards Organization [11]. 

Table 3.1 Illustrative example of the calculation of a size distribution by number using the British Standard globe and circle graticule...

BS 3625 (1963) Microscope eyepiece and screen graticule. British Standards Institution, London. 

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