A handbook of house sanitation : for the use of all persons seeking a healthy home ; a reprint of those portions of Mr. Bailey-Denton's lectures on sanitary engineering given before the school of military engineering, Chatham, which related to the "dwelling."

John Bailey Denton

Date:: 1882

Credit: A handbook of house sanitation : for the use of all persons seeking a healthy home ; a reprint of those portions of Mr. Bailey-Denton's lectures on sanitary engineering given before the school of military engineering, Chatham, which related to the "dwelling.". 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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$Impermeable granites and marbles of the greatest possible density hold about a pint of water per cubic yard, while a loose sand will contain from 40 to 50 gallons per cubic yard. Ordinary red sandstone will hold 27 gallons per cubic yard. XVI. Improvement of Temperature consequent upon Under-drainage.—The advantage of lowering the sub-soil water, and of admitting air into the soil does not, however, end with the reduction of special diseases. This work has the effect of im- proving the temperature of the air incumbent upon the ground, as well as of raising that of the soil beneath. If the rain falling on the ground is absorbed and cannot escape from the sub-soil because no oudets exist to carry it away, it is evaporated from the surface; and, supposing 30 inches of rain to fall in a year on an acre of land, and its evaporation to be spread over the whole period, the daily weight of water evaporated would be rather more than 8^ tons or 18,596 lbs. ' ^ , . , An engineer will best realize the loss of neat, i.e., the reduction of temperature resulting from the change of such a quantity of water into vapour, when he remembers that it would require the combustion of about 24 cwt. of coals as ordmarily used under a steam boiler to effect the object {Josiah Parkes) ■ ceteris paribus, the amount of water evaporated is proportional to the surface exposed to the air. It is much greater from porous solid surfaces kept wetted-as, for example moist soil wetted by rain—than from the surface of water itself {Herschel). Every grain of water evaporated, carries off with it sufficient heat to raise q6o grains i degree Fahr. . , ^ . •, , Mr Buchan, of the Scottish Meteorological Society, has shown bv his'experiments that the temperature of the drained sod has been raised in summer above that of undramed land to the extent of 3 degrees, often 2 degrees, and still more frequently a degree and a half hence it follows that the advantage derived from drainage is, in many cases, the same as if the land had been transDorted 100 to 150 miles southward. . , , T Wniiam Rankine showed ^o^rnal of the ScotUsh Meteorolo- deal Society, 1865) that the mean temperature of land was raised by Sde^^-d %age at 10 inches from the surface eight-tenths of a Se^ee wS^^ experiments I made at Hmxworth E!;:iZncultural^Soeiety of England -1- x8 o sho.^^^ that in spring the temperature of dramed land at 18 inches trom t'he urflce las 2 degLs higher than that o t^e -dj^ed ^^^^^^^^ o, >V,A c:amft deoth The experiments of the late Josiali i-arKes, near BSnJe-Moors, showed an increase in the temperature of drained and over undrained bog, of lo degrees at 31 inches below fhe surface V'On the influence of water on t)^ temperature of sod. fouZTTftL Royal Agricultural Soaety of England, vol. v.]$