The microscope: its history, construction, and application : being a familiar introduction to the use of the instrument and the study of microscopical sciences / by Jabez Hogg.

  • Hogg, Jabez, 1817-1899.
Date:
1869
Catalogue details

Licence: Public Domain Mark

Credit: The microscope: its history, construction, and application : being a familiar introduction to the use of the instrument and the study of microscopical sciences / by Jabez Hogg. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    appeared distinct and prodigiously magnified when held close to his eye, concluded, that if he placed a globule of Water in which there were any particles more opaque than tlie water near his eye, he should see those particles dis- tinctly and highly magnified. The result of this idea far exceeded his expectation. His method was, to take on a pin a small portion of water which he knew contained some minute animalcules; this he laid on the end of a small piece of brass wire, till there was formed somewhat more than a hemisphere of water; on applying it then to the eye, he found the animalcules enormously magnified ; for those which were scarcely discernible with his glass globules, with this appeared as lai’ge as ordinary-sized peas. Dr. Hooke thus describes the method of using this water-microscope: “If you are desirous,” he says, “of obtaining a microscope with one single refraction, and consequently capable of procuring the greatest clearness and brightness any one kind of microscope is susceptible of, spread a little of the fluid you intend to examine on a glass plate ; bring this under one of your globules, then move it gently upwards till the fluid touches the globule, to which it will soon adhere, and that so firmly as to bear being moved a little backwards or forwards. By looking^ through the globule, you will then have a perfect view of the animalcules in the drop.” The construction of the single microscope is so simple, that it is susceptible of but little improvement, and has therefore undergone few alterations ; and these have been chiefly confined to the mode of mounting it, or to addi- tions to its apparatus. The gi-eatest improvement this instrument has received was made by Lieberkuhn,i about the year 1740 : it consists in placing the small lens in the centre of a highly-polished concave speculum of silver, by which means a strong light is reflected upon the upper surface of an object, which is thus examined with great ease and pleasure. Before this contrivance, it was almost impossible to examine small opaque objects with any degree of e.xactness; for the dark side of the object being next the eye, and also overshadowed by the proximity ot (1) Dr. Nathaniel Lieberkuhn of Berlin. «