Chapter II 

 INCREASED PRESSURE 



Subchapter I 



OBSERVATIONS, THEORIES, AND RECENT 

 DISCUSSIONS 



1. High Pressures. 



The study of high barometric pressures has not been the subject 

 of any recent work. The results of my experiments on the action 

 of oxygen at high tension were accepted without dispute, I might 

 even say without criticism, by physiologists. Similarly, for the 

 effects of sudden decompression and their explanation demon- 

 strated by my researches, no new fact, either in industry or in 

 science, has been produced which can be reported here. I shall 

 except only a very interesting work of M. Guichard, 1 an engineer 

 with great experience in the use of compressed air and personally 

 very skilled in the use of the diving-suit. 



The article of M. Guichard is composed of two kinds of observa- 

 tions. The most numerous relate to the stay in poisonous gases 

 (CO, CO., C 2 H 4 , S0 2 , etc.) ; these, in spite of their great practical 

 interest, and the dramatic details of one of them (Observation 

 VIII) , have no connection with the subject of our research. In the 

 others, it is a question of respiration in compressed air; I quote two, 

 interesting for various reasons: 



Observation XIV. Seven divers were successively seized by 

 epistaxis under a pressure of a column of water of 9 meters. To show 

 the use of a new apparatus for artificial respiration, I descended into 

 a vast masonry basin containing very clear water at a depth of 9 

 meters. The ascent and descent were executed without any time pre- 



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