The practical use of meteorological reports and weather-maps / Office of the chief signal officer, Division of telegrams and reports for the benefit of commerce.

  • United States Army Signal Corps
Date:
1871
Catalogue details

Licence: Public Domain Mark

Credit: The practical use of meteorological reports and weather-maps / Office of the chief signal officer, Division of telegrams and reports for the benefit of commerce. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

    74/96 (page 64)
    When the temperature iu both thermometers is the same (or the diifereuce 0°) evaporatiou from tbe moist muslin on the wet- bulb has entirely ceased, the quicksilver in its tube has ceased to fall, and, of course, the relative humidity is that of full sat- uration, or 100, as is shown by the second vertical column iu Table ]So. 1. THE WET AND DRY BUI.B THERMOMETER. Table ITo. 1 is used but seldom, because it is adapted for extreme temperatures below the freezing-point of fresh w^ater, (32° Fahrenheit.) It gives the relative humidity iu the vertical columns for differences of each half degree between the two ther- mometers, and when the wet bulb falls as low down as 0°. Whenever the wet-bulb stands at any figure between 0° and 9° above 0° (inclusive) use lower part of Table No. 1. In other cases table ISTo. 2. These tables are compiled from Meteorological and Physical Tables, prepared for the Smithsonian Institution, by A. Guyot, third edition, Washington, 1859.