On an easy method of viewing certain of the diatomaceæ / by John Charles Hall.

  • John Charles Hall
Date:
[between 1800 and 1899]
Catalogue details

Licence: Public Domain Mark

Credit: On an easy method of viewing certain of the diatomaceæ / by John Charles Hall. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    On an Easy Method of viewing certain of the Diatom ace/e. By John Charles Hall, M.D., Physician to the Sheffield Public Dispensary, &c. &c. We shall most certainly add not a little to the chances of increasing our knowledge of the intimate structure of the infusorial tribes, if any means can be suggested by which the number of observers may be increased. Possessed of a good microscope by one of our principal makers, a student may imagine that he is in a condition at once to ascertain the exact form and nature of certain shells of Bacillaria, certainly amongst the most difficult of test objects; a very few trials will, however, convince him that even the best-constructed eighth will not fully display their peculiar markings without some accessory instrument For this purpose the achromatic condenser of Mr. Gillet, as made by Mr. Ross, or the achro- matic condenser of Powell and Lealand, or of Smith and Beck, is usually employed. The purse, unfortunately, of the most enthusiastic labourers is not always the heaviest; a mi- croscope is bought and added to from time to time, and the condenser, so much coveted, must often be waited for some years. We propose in the present paper to show how, for a few shillings, this apparatus may, for a time at least, be dispensed with; and how the Pleurosigma Hippocampus, Pleurosigma formosum, Pleurosigma angulatum, and other individuals of this genus, may be shown in the most satisfactory manner; and we almost envy the sensation of delight which must be experienced on using this simple means of illumination, and beholding for the first time the wonderful markings and brilliant colouring of many of these dust-like atoms, found alike in the clearest waters, in the strongly acidulated, and in the salt fluids of the various zones of the earth. “ In springs, rivers, lakes, and seas, in the internal moisture of living plants and animal bodies, exists,” says Pritchett, “ a world, by the common senses of mankind unperceived; for, in the ordinary pursuits of life, this mysterious and infinite kingdom of living creatures is passed by without knowledge of, or interest in, its wonders.” To facilitate the investigation of these wonderful organizations the present paper has been written. A
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