Air, water and food from a sanitary standpoint / by Ellen H. Richards and Alpheus G. Woodman.

  • Richards, Ellen H. (Ellen Henrietta), 1842-1911.
Date:
[1904], [©1904]
Catalogue details

Licence: Public Domain Mark

Credit: Air, water and food from a sanitary standpoint / by Ellen H. Richards and Alpheus G. Woodman. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    upon the legal questions connected with tenements and fac- tories, must often rely upon chemical examinations of the air. The validity of these depends not only upon the per- fection and delicacy of apparatus and methods used, but also upon the judgment and intelligence with which the samples are taken. Many errors in the construction of buildings have been perpetrated because of an ignorance of the physical proper- ties of air and, consequently, a mistaken notion of the be- havior of a vitiated atmosphere. The lecturer on popular science who some forty years ago enlightened (?) the com- munity on the chemistry of daily life was accustomed to use, as a striking illustration, a glass jar in which a small lighted candle was instantly extinguished on pouring into the jar a tumblerful of carbon dioxide which had been collected for the purpose. The inference was plain: carbon dioxide was heavier than air, therefore it falls to the floor and must be allowed to flow out as if it were a stream of water. Further confirmation of this inference was found in the frequently observed fact that a candle lowered into a well often went out just before the water was reached. Hence for many years the habits of thoughtful persons were formed on a belief in the heaviness of carbon dioxide or bad air, and in its tendency to go to the bottom of the room and into any holes it could find. This is only another instance of danger in half a truth. When do we find cold carbon dioxide generated in living-rooms? And how warm must the gas be in order to be lighter than the ordinary air? How quickly does diffusion take place? Until within a very few years the almost unanimous belief among the so-called educated classes was that the bad air could be let out by opening a window at the bottom, and, in spite of the lessons which might have been learned by any observant person in