Observations on the construction of healthy dwellings : namely houses, hospitals, barracks, asylums, etc. / by Sir Douglas Galton.
- Galton, Douglas, Sir, 1822-1899.
- Date:
- 1896
Licence: Public Domain Mark
Credit: Observations on the construction of healthy dwellings : namely houses, hospitals, barracks, asylums, etc. / by Sir Douglas Galton. Source: Wellcome Collection.
Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.
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![The mean rate of increase over the globe may be approxi- mately assumed at ] ° Fahrenheit for every 50 feet in depth. The internal heat exercises, under certain conditions, an influence over the mean temperature of the surface soil of a locality. Where the rainfall is tolerably evenly divided over the year, the average annual temperature of the soil will be that of the climate of the locality. But in countries with distinct wet and dry seasons, the mean temperature of the soil will not necessarily be the same as that of the mean temperature of the air. Snow, being a bad conductor, prevents the passage of the heat from the earth into the air, and thus in countries where snow lies for some time on the ground, the mean temperature of the earth exceeds that of the air. The temperature of water in permanent springs is neces- sarily derived from the subsoil line of fixed temperature, and, except in the cases just alluded to, it will not be found to vary more than i° or 2° from the mean temperature of the locality; therefore the temperature of a permanent spring may be assumed to afford a certain guide to the mean temperature of a district. Thus, in England, the permanent springs range in tem- perature from 49° to 51°, the mean annual temperature being 500. In India the springs will be found to vary in different parts, according to the temperature of the locality; in some instances they attain a temperature of from 700 to 8o°. But whilst the mean temperature of the ground depends on the climate, soils have a very varying conducting capacity for heat; loam, clay and rocks are better conductors than sand, and by allowing the sun's heat to pass more rapidly down- wards, do not become heated to so high a degree. The conducting capacity of the soil has a very important bearing upon the comfort, if not upon the health, of those who live upon it. The following table shows the relative power of soils to](https://iiif.wellcomecollection.org/image/b21023724_0027.jp2/full/800%2C/0/default.jpg)
