Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-12-03T19:23:53.756Z Has data issue: false hasContentIssue false
  • English
  • Français

Estimation of Humidity with Cobalt Thiocyanate Papers and Permanent Colour Standards

Published online by Cambridge University Press:  10 July 2009

M. E. Solomon
M. E. Solomon
Affiliation:
Department of Scientific & Industrial Research, Pest Infestation Laboratory, Slough, Bucks.
Get access Rights & Permissions [Opens in a new window]

Extract

The method of measuring relative humidity by matching the colours of tissue paper impregnated with cobalt thiocyanate has now been made more convenient by the commercial production of impregnated paper and coloured glass standards.

Although the method as used straightforwardly is not at all precise, it is especially useful for the measurement of humidity in small or relatively inaccessible spaces, e.g., cracks in floors, air spaces in stored grain, under bark, or inside small tubes, etc., and for general use when elaborate equipment cannot be employed.

A piece of the paper is exposed to the humidity to be measured, preferably for two hours, then mounted on white opal glass in oil (liquid paraffin) and matched, in a simple comparator, against the coloured glass standards. When matching is done at a temperature other than 20°C., corrections are required as tabulated.

Tables of error are given, showing the range of variation from different causes, with estimates of 95 per cent, confidence limits. To cover all the sources of variation normally affecting the measurements under various conditions, limits up to ±5 are allowed for relative humidities down to 70 per cent.; these limits increase at lower humidities to a maximum of ±15, about 30 per cent. Various ways of avoiding errors are described, and it is shown that if special precautions are taken the method can be used with considerable accuracy, particularly at relative humidities above 65 per cent.

Type
Original Articles
Information
Bulletin of Entomological Research , Volume 48 , Issue 3 , September 1957 , pp. 489 - 506
Copyright
Copyright © Cambridge University Press 1957

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Atkinson, L. B. (1923). Improvements in and relating to hygrometers, hygroscopes and the like.—Brit. Pat. Specification 226,366 (No. 32,100/23).Google Scholar
Broadhead, E. & Thornton, I. W. B. (1955). An ecological study of three closely related psocid species.—Oikos, 6, pp. 1–50.CrossRefGoogle Scholar
Chatt, J., Duncan, G. H., Gregson, H. & Wilde, E. (1948). Improved humidity indicators.—Brit. Pat. Specification 610,976 (No. 11953/46).Google Scholar
Cragg, J. B. (1950) Studies on Lucilia species (Diptera) under Danish conditions.—Ann. appl. Biol., 37, pp. 66–79.CrossRefGoogle Scholar
Darrow, C. W. (1943). Physiological and clinical tests of autonomic function and autonomic balance.—Physiol. Rev., 23, pp. 1–36.CrossRefGoogle Scholar
Davies, L. (1948). Observations on the development of Lucilia sericata (Mg.) eggs in sheep fleeces.—J. exp. Biol., 25, pp. 86–102.CrossRefGoogle Scholar
Davis, P. B. & Pryor, J. N. (1950). Moisture indicator.—U.S. Pat. No. 2,526,938. (Brit, Abstr., (C) 1952, (2), 695.)Google Scholar
Delany, M. J. (1953). Studies on the microclimate of Calluna heathland.—J. Anim. Ecol., 22, pp. 227–239.CrossRefGoogle Scholar
Eder, R. (1940). Die kuticuläre Transpiration der Insekten und ihre Abhängigkeit vom Aufbau des Integumentes.—Zool. Jb., (Abt. 3) 60, pp. 203–240. (Biol. Abstr., 15, 20358.)Google Scholar
Goodwin, M. E. & Simpson, E. A. (1953). Relative-humidity indicator.—U.S.Pat. No. 2,627,505. (Brit, Abstr., (BI) 1953, (Nov.), 1168.)Google Scholar
Henderson, F. Y. (1936). The preparation of “three-colour” strips for transpiration measurements.—Ann. Bot., Lond., 50, pp. 321–324.Google Scholar
Horita, Y. (1954). Simple method of determining moisture with cobalt chloride.—Japan Analyst, 3, p. 330. (Chem. Abstr., 49, (21), 14572c.)Google Scholar
Livingston, B. E. & Shreve, E. B. (1916). Improvements in the method for determining the transpiring power of plant surfaces by hygrometric paper.—Plant World, 19, pp. 287–309.Google Scholar
Macfadyen, A. (1953). Notes on methods for the extraction of small soil arthropods.—J. Anim. Ecol., 22, pp. 65–77.CrossRefGoogle Scholar
Morton, J. E. (1954). The crevice faunas of the upper intertidal zone at Wem-bury.—J. mar. biol. Ass. U.K., 33, pp. 187–224.CrossRefGoogle Scholar
Pomeranz, J. & Lindner, C. (1953). A simple method for the evaluation of moisture in milled products.—Bull. Res. Coun. Israel, 3, p. 251. (Food Sci. Abstr., 26, (5), 2683.)Google Scholar
Snedecor, G. W. (1946). Statistical methods.—4th edn., 485 pp. Ames, Iowa, Iowa St. Coll. Pr.Google ScholarPubMed
Solomon, M. E. (1945). The use of cobalt salts as indicators of humidity and moisture.—Ann. appl. Biol., 32, pp. 75–85.CrossRefGoogle Scholar
Solomon, M. E. (1951). Control of humidity with potassium hydroxide, sulphuric acid, or other solutions.—Bull. ent. Res., 42, pp. 543–554.CrossRefGoogle Scholar
Ward, C. B. & Tischer, R. G. (1953). Use of cobaltous chloride to detect moisture patterns in partially dehydrated kernels of corn.—Cereal Chem., 30, pp. 420–426.Google Scholar
Wetherell, H. E. (1905). Hygrometry.—4th edn.Philadelphia, Ellis Johnson. (Cited in Darrow, 1943.)Google Scholar