[On foul air and lung disease : a lecture] / by Arthur Ransome.

  • Ransome, Arthur.
Date:
[between 1870 and 1879?]
Catalogue details

Licence: Public Domain Mark

Credit: [On foul air and lung disease : a lecture] / by Arthur Ransome. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    The result of all this is that the air is necessarily charged with many adventitious substances; and yet owing to the vastness of its extent, and its power of diffusing gases and vapours through- out its area, and also owing, as we shall presently see, to its power of altering the nature of what is poured into it, it really has a most wonderful uniformity of composition. Many of the substances that pass into it are to be found only in very minute quantities even in the immediate neighbourhood of their source; and, on the other hand, the air collected in mid-ocean or over the unsul- lied snows of Mont Blanc can be shown, by the delicate processes of modern chemistry, to contain traces of these substances. The air is, in fact, in great measure self-purifying. _ In the great laboratory of the sky, chemical and electrical operations are con- stantly going on on the grandest scale ; the heated air rises, cooler currents rush in to supply its place; breezes, winds, and storms arise and act as agents that move on any gases and vapours or any product of putrefaction, and mix them up in the vast depths: of the aerial sea, and there they are not only diluted, but con- verted into harmless substances. We know but little of the balancings of the clouds, but we may be sure that within their recesses all organic matter and impurity is burnt up as certainly as if it had passed through a furnace; the oxygen of the an, in- tensified in its power by electricity, fastens upon it and changes it into the ultimate products of combustion—carbonic acid, aqueous vapour, ammonia, or nitric acid. Even without wind, any excess of gas is immediately removed by means of what was called by our great townsman, Dr. Dalton, the diffusion of gases. Simply stated, this means that any gas can pass into the interstices between the particles of another gas, and thus mix itself up with it as readily as if it were passing into empty space. Then, again, when the condensed vapour of which the clouds are composed is precipitated in the form of ram, it washes down some of these altered products, and prevents any excess from re- maining there. . . It has been calculated that 90,000 cubic miles of ram fall upon the face of the globe in the course of a year, and that it washes down in this time no less than i£ millions of tons of ammonia. When we remember the great value of this substance to the farmer, and how that it is the chief part of his richest manures, we see at once both what a tremendous system of scavenging is being., carried on, and what an invaluable assistance the product is to the growth of food for mankind.
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