Observations on the medical and surgical agency of the air-pump : read before the British Association, in 1835 / by Sir James Murray.

Date:
1836
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the medical and surgical agency of the air-pump : read before the British Association, in 1835 / by Sir James Murray. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    &c. &c. PART I. OF RAREFACTION. Fishes, at a depth of about thirty-four feet of water, sustain a pressure of fifteen pounds upon every square inch, exclusive of the superincumbent atmosphere. This is the gravity of a column of water an inch square, by the above mentioned height. In like manner, all bodies placed in the ocean of atmospheric air around us, are pressed by a similar weight. A column of air of ordinary density -and tempe- rature, from the level of the sea, to the highest range or top of the atmosphere, by an inch square, weighs fifteen pounds. Now, as the human body, like all others, is sustaining the above weight on every square inch, it results, that the superficies of a man, being in general, rather more than fifteen square feet, multi- plied by fifteen pounds for every square inch, must