The investigation of mine air : an account by several authors of the nature, significance, and practical methods of measurement of the impurities met with in the air of collieries and metalliferous mines / edited by Clement le Neve Foster and J.S. Haldane.

  • Foster, Clement le Neve, Sir, 1841-1904.
Date:
1905
Catalogue details

Licence: In copyright

Credit: The investigation of mine air : an account by several authors of the nature, significance, and practical methods of measurement of the impurities met with in the air of collieries and metalliferous mines / edited by Clement le Neve Foster and J.S. Haldane. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    iTyten dissociated into hemoglobin and recei 4 a .1 ^T^' ^^^'^ Wood, to receue a new charge of oxygen and once more become o^;tn'car' 1 • ^'^ hemoglobin wTh prSure o? Tp^ accomphshed in the lungs if the partial pressure of the oxygen m the air which is being inhaled is lAciently great Experiments have shown that 1.h s can be lowered to one-half of the normal without injury to health I V>ZerT:^^^^^^ sunk below U per cent, that dilBculties of breathing set in: with 10 per cent the hps become bluish; with 6 percent, there is violent pa pztation of the heart and loss of cozLiousness, which is soon folWed by death. The experiences of person^ going up i ba loons or ascendmg high mountains are in complete accord with the above facts for it is found that difficulties of breathing ommence at a height of about 5000 metres (16,000 feet), whe? the atmospheric pressure is reduced to about one-half of what't IS normally and when consequently the partial pressure of the oxygen m the inhaled air has likewise sunk to one-half. On the npntL^T 'f''' air-pressure may partially com- pensate for the reduction in the percentage of oxygen. Conse- quently a diminution in the oxygen contents of the^tmospC IS more easily borne at a great depth than at the surface. The partial pressure of the oxygen in the inhaled air may be increased threefold without injury to health; and pure oxygen mly be inhaled into the lungs for a long time without^^dange^^ As blood m contact with pure oxygen saturates itself with this gas five times as quickly as it does when in contact with air, persons who have been suffocated from want of oxygen are made to breathe pure oxygen m the hopes of restoring them to life. Compressed oxygen contained in steel bottles is a regular article of commerce 2. Nitrogen. Of the various substances existing in the gaseous state upon the earth, nitrogen is the one which occurs in the largest .luantitv Our atmosphere contains nearly four-fifths of its volume of nitrogen ; more exactly, it contains 78-1 per cent, of nitroo-en by volume Although the percentage of oxygen in the air fs very constant the proportion of nitrogen is almost more so as it scarcely has any share in the active chemical changes which are continually going on in our planet. It is only a few plants