This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...employed. The use of monobromoiiaphthalene immersion objectives has been tried, but they do not appear to have achieved any widespread use. An effort has also been made to meet this requirement by the use of light of much shorter wave-length. The author has spent a considerable amount of time in endeavouring to use the Zeiss ultra-violet microscope for metallurgical purposes, and has succeeded in obtaining a few micrographs by this means. He has, however, abandoned his efforts, because the expenditure of time required was much too great, while the results themselves were not particularly satisfactory. One of the main difficulties in his experience arose from the internal scattering of the ultra-violet light and the occurrence of fluorescence within the microscope tube. Even should it be possible to overcome these difficulties, a process which is entirely photographic, and in which the systematic visual examination of relatively large area of specimens is impossible, does not promise a very large range of utility. Reverting to the requirements for objectives of the ordinary type intended for metallurgical use, there is one point which requires special emphasis and attention. Clear images, whether visual or photographic, can only be obtained if serious reflections of light from the back surface of the objectives can be avoided. As has been indicated above, this is partly a question of careful adjustment of the light and of the illuminator. With the best of facilities in that direction, however, the author's experience has shown very clearly that different lenses of the same focal length differ very widely in respect of this matter of internal reflections. This appears to be a question of the shape of the back lens of the objective, and especially of the outer...
"synopsis" may belong to another edition of this title.