Practical microscopy / by George E. Davis.

  • George E. Davis
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: Practical microscopy / by George E. Davis. Source: Wellcome Collection.

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    objects, either by means of the mirror or the achromatic prism. There is also a graduated silver circle, which can be used as a goniometer or for a variety of purposes. The substage has rotary, vertical, and rectangular motions, and both stages have for their foundation a solid brass ring, firmly attached to the stem. Messrs. R. & J. Beck make many forms of microscopes, but their u Pathological,” shown in Fig. 7, is perhaps the most useful to the real worker. It has been specially designed with a view of applying everything necessary for clinical and bacteriological work to a small instrument. It has a lever fine adjustment, and a rack and pinion substage with centering screws, carrying a wide-angle achromatic condenser, accurately corrected for spherical aberration. The stage is of glass, and therefore not mechanical, but for the kind of work it is intended for this is no drawback. This chapter is not intended to be merely a catalogue of microscopes, but is designed to show the would-be purchaser the various forms there are in the market to aid him in the task of selection. It is not our intention to elevate or disparage the productions of any maker in particular, but we do advise the beginner to be very careful in the selection of an instrument, as we have nearly always found, that if anyone has rushed blindly into the purchase of a microscope, on the recommendation of a friend, sooner or later he has been dissatisfied with it and has finally purchased another of his own choice. It is a good plan before deciding to purchase, to attend several of the microscopical soirees now so popular during the winter months. The would-be microscopist can there see many patterns of instruments and will be able to gain some valuable information by talking over their merits and demerits with the possessors. The exceedingly large stands will not be found very handy for every-day work, they are