Aids to the mathematics of hygiene / [Robert Bruce Ferguson].

  • Ferguson, R. Bruce (Robert Bruce)
Date:
1904
Catalogue details

Licence: In copyright

Credit: Aids to the mathematics of hygiene / [Robert Bruce Ferguson]. Source: Wellcome Collection.

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    density of aqueous vapour compared with air—viz., by 0-622 (p. 3). Therefore, t cubic foot of aqueous vapour at 6o° F. weighs 9-29x0-622 = 577 grains. Example: What weight of aqueous vapour is contained in a cubic foot of air which is saturated at a temperature of 6o° F. ? Dalton’s law states that ‘ the tension, and conse- quently the quantity of vapour which saturates a given space, are the same for the same temperature, whether this space contains a gas or is a vacuum.’ Therefore, the weight of aqueous vapour in a cubic foot of air is the same as if the space had been empty of air ; so the question resolves itself into, What is the weight of a cubic foot of aqueous vapour at 6o° F. ? [Ans. : 577 grains.] SATURATED AIR. To find the Weight of a Given Volume of Saturated Air at a Given Temperature and Pressure. The mass of air may be divided into two parts—viz., a volume of dry air, and a volume of aqueous vapour ; and the sum of the weights of these two volumes is the weight required. Let P = the pressure of the moist air ; and / = the elastic force of the vapour which saturates it. Then the air alone in the mixture only supports a pressure of P —p.
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