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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    to be taken as a basis for the microscopic object-glass; it diminishes very nearly half the loss of light from reflec- tion, which is considerable at the numerous surfaces of a combination; the clearness of the field and brightness of the picture is evidently increased by doing this; and it prevents any dewiness or vegetation from forming on the inner surfaces. Since this time, Mr. Eoss has been con- stantly employed in bringing the manufacture of object- glasses to their greatest perfection, and at length they have attained to their present improved manufacture. Having applied Mr. Lister’s principles with a degi'ee of success never anticipated, so perfect wei’e the corrections given to the achromatic object-glass, so completely were the errors of sphericity and dispersion balanced or de- stroyed, that the circumstance of covering the object with a plate of the thinnest glass or talc disturbed the coiTections, if they had been adapted to an uncovered object, and rendered an object-glass which was perfect under one condition sensibly defective under the other. Here was another and unexpected difficulty to be over- come, but which was finally accomplished; for in a com- munication made to the Society of Arts in 1837, Mr. Eoss stated, that by separating the anterior lens in the combi- nation from the other two, he had been completely suc- cessful. The construction of this object-glass will be illustrated and explained in a future chapter. The rapid improvement in the manufacture of the achromatic compound microscope in this country has been greatly furthered by the spirit of liberality evinced by Sir David Brewster, the late Dr. Goring, kir. E. H. SoUy, and Mr. Bowerbank. To the patronage of Dr. Goring we owe the constniction of the first triplet achromatic object-glass, of the diamond lens, and of the improved reflecting instrument of Amici by Cuthbert. The achromatic microscopes now manufactured by our London makers, Mr. Eoss, Messrs. Powell and Lealand, and Messrs. Smith and Beck, are unequalled in any part of the world. This opinion is confirmed by the reports of the juries on the Exhibition of Works of Industry of all Nations, 1851; at that time the instruments exhibited by Mr. Eoss and Messrs. Smith and Beck, by far excelled