A manual of elementary microscopical manipulation for the use of amateurs / by T. Charters White.

  • White, T. Charters (Thomas Charters), 1828-1916.
Date:
1887
Catalogue details

Licence: Public Domain Mark

Credit: A manual of elementary microscopical manipulation for the use of amateurs / by T. Charters White. Source: Wellcome Collection.

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    evolution of a natural interest has been stilled bv a premature attempt to mentally grasp what only a trained eye can comprehend. Before the student commences the work of his micro- scopical observations, it is necessary that he should pi o' ide himself with a few indispensable appliances; to assist him. a brief enumeration may save trouble;— Glass Slides— Before observing any transparent object under the microscope, it must lie supported on the stage >■! the instrument on a glass slide beneath the objective. I hose glass slips, procurable of any optician, are of a standard sizo of three inches long, by one inch wide. 1 hey should be of patent plate, free from bubbles and stria', and ground at the edges. They are not exjiensive, as they may l>e cleaned and used over again should the mounted object not be satisfactory. If they have been used for Canada balsam mounting, a short immersion in methylated spirit, to which some liquor potassm has been added, will quickly remove tho mounting medium, when the slide may be washed in warm water, and wiped clean, ready for further use. If the object under examination be opaque, such as seeds, pollen, grains of flowers, eggs of insects, and such like, the rays of light may be concentrated on them by the condensing lens, which is sufficient preparation: indeed, a juster idea of the nature of the object may be formed by this method than by any other; but if the object is intended to be examined by transmitted light reflected from the mirror beneath the stage, then it is desirable to place the object under a covering glass to keep it flat. Cover Glasses.—These, also obtainable at the opticians, are of differing degrees of thinness, varying from one- fiftieth to one three-hundredth of an inch in thickness. Unless the magnifying power employed be greater than one-sixth of an inch focal length, it is advisable for the