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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    purchased by the late Duke of Buckingliam, and another tlie thirtieth of an inch focus. In March 1825, M. Chevalier presented to the Society for the Encouragement of the Sciences, an achromatic lens of four lines focus, two lines in diameter, and one line in thickness in the centre. This lens was greatly superior to the one befoi'e noticed, which had been made by him for M. Selligues. In 1826, Professor Amici, of Modena, who from the year 1815 to 1824 had abandoned his experiments on the achromatic object-glass, was induced, after the report of Fresnel to the Academy of Science, to resume them; and in 1827 he brought to this country and to Paris a hori- zontal microscope, in which the object-glass was composed of three lenses superposed, each having a focus of six lines and a large aperture. This microscope had also extra eye- pieces, by which the magnifying power could be increased. A microscope constructed on Amici’s plan by Chevaliei', during the stay of that physician in Paris, was exhibited at the Louvre, and a silver medal was awarded to its maker.' “ While these practical investigations were in progress,” says Mr. Koss, “the subject of achromatism engaged the attention of some of the most profound mathematicians in England. Sir John Herschel, Professors Airy and Barlow, Mr. Coddington, and others, contributed largely to the theoretical examination of the subject; and though the results of their labours w’ere not immediately applicable to the microscope, they essentially promoted its im- provement.” Mr. Jackson Lister, in 1829, succeeded in forming a combination of lenses updn the theory propounded by these gentlemen, and effected one of the gi-eatest improve- ments in the manufacture of objecbglasses, by joining together a plano-concave flint lens and a convex, by means of a transparent cement, Canada balsam. This is desirable (1) In 1855, when the Jury on Microscopes at the Paris Exposition were com- paring the rival instruments, Professor Amici brought a compound achromatic microscope, comparatively of small dimensions, which exhibited certain strim in test objects better than any of the instruments under examination. This superiority was produced by the introduction of a drop of water between the object and the object-glass.