CHAP. XIX. THEORY. 379 



fell temporarily, and seemed fascinated by the experiment. They 

 received, however, several very emphatic indications of the danger 

 attendant upon rapid diminution of pressure,^ which were con- 

 firmed upon an actual balloon ascent made thirteen days later. 

 Taking no warning from tliese premonitory symptoms, on April 15, 

 1875, they left the earth at 11.35 a.m., and in two hours rose to 

 the height of about 26,000 feet, and for two hours more hovered 

 about 26-28,000 feet. At the end of this time both were found 

 suffocated, with their mouths full of blood ; but neither the time 

 nor the elevation at which they died is known exactly, as M. 

 Tissandier, the sole survivor of the party, was rendered insensible, 

 and thus was unable to give a complete account of the affair. 



Various suggestions were made as to the immediate cause of 

 their death, and upon these Prof. Bert remarks (p. 1075) that none 

 deserve to be reproduced, they are " old ideas, already condemned^' ; 

 and to the end of his volume (which was published three years after 

 the catastrophe — allowing him ample time to reconsider his posi- 

 tion) he maintains (1) that deficiency of oxygen was the cause of 

 the death of these aeronauts and of all the evils that are produced 

 by diminution in pressure, and (2) that artificial inhalation of 

 oxygen is the sovereign remedy. It does not appear that he took 

 the practical course of remaining in his cylinder for a length of 

 time, at a pressure corresponding to that which proved fatal to his 

 pupils.^ If he had done this, and had emerged alive, he would 

 have made out a strong case. 



Prof. Bert omits to state what effect is produced on Respiration 



1 Notwithstanding the draughts of oxygen, their pulses rose to 132 and 135, 

 They experienced a sort of drunken sensation and could neither see nor hear clearly. 

 One of them commenced to eat and soon stopped ; " and when I made," says M. 

 Bert, ''a sign to him to continue, he answered me with a gesture of disgust." 

 Upon their balloon ascent on Mar. 22, 1874, they experienced strong pressure in 

 the head. 



2 Whose death seems to have exercised a deterrent effect upon aeronauts. There 

 has not been, I believe, any subsequent attempt to reach the elevation at which 

 they perished, and I have not heard that any one, since 1875, has even soared so 

 high as twenty thousand feet. 



