Minutes of proceedings of the Royal Artillery Institution (1858)
Great Britain. Army. Royal Artillery Institution · Woolwich, Eng., : The Institution · leaf 400
be, directs a constant beam of light on the back of the glass circle at P. “ The bright field illumination is effected by a very small central reflector, R't which sends the light directly into the field of the micrometer. “ This method is, I believe, now generally considered to give the best…
Artillery -- Periodicals · Artillery -- Great Britain -- Periodicals
Internet Archive · Smithsonian Libraries · Public domain (published before 1931). Free to use for anything.
