Diving Bells and Suits 383 



were covered with sand, which even penetrated the skin, and remained 

 for a few moments as if stupefied, but none of them was seriously ill. 



This result does not agree with what had been told me; but M. 

 Wolff was on his rounds at the moment of the accident; and M. 

 Counord was ill; it seems more certain to trust the version of a witness 

 though it is almost the opposite. Moreover, this man was present at 

 a similar accident, at the time of the construction of the bridge of 

 Bordeaux; there too, no death was caused by the sudden decom- 

 pression; two men only were killed by fragments of iron. 



But if a sudden decompression of more than three atmospheres 

 was not fatal, this change, though moderated by a stay of 4 or 5 

 minutes in the equilibrium chamber, was none the less dangerous in 

 the long run. According to M. Counord, 90% of the workmen were 

 ill, all attacked by violent pains in the joints, oppression, disturbance 

 of vision, etc. The foreman whom I saw was attacked three times, 

 and suffered greatly, but never more than a day. One morning, out 

 of eleven men who were leaving, nine were seized with pains after 

 a few moments. 



Certainly it is not impossible that the decompression had some- 

 thing to do with the death of the two workmen who were buried 

 in the wet sand; but that is not proved. The strangest thing in this 

 observation is to see men experiencing almost no symptom after 

 an instantaneous decompression from at least 4 atmospheres. 



In 1865, there was a similar foundation under the Louet, at 

 Chalonnes (Maine-et-Loire) , for the bridge of the line from Angers 

 to Niort. A catastrophe as yet unexplained killed two workmen: 



February 20, 1865, when pier number 2 had reached bed rock, 

 at a depth of 14 meters below the low-water mark, when everything 

 seemed finished, when the work-chamber was already filled with 

 concrete, and when the caisson, like a chimney, was also filled up to 

 a depth of 5 meters, suddenly a violent explosion occurred and half 

 of the metal roof of the equilibrium chamber " was hurled about 30 

 meters away. Two laborers, who were in the work-room, were 

 crushed. No explanation for this terrible accident has yet been found. 

 (Lectures on Bridges by M. Morandiere) 



It is probable that in this case, for some unknown reason, the 

 tension of the compressed air had risen far above that required by 

 the depth reached; the force of the explosion proves that. 



I am endebted to Dr. Gallard for some interesting details about 

 this distressing accident: 



The death of the two workmen (this learned colleague writes me) 

 was almost instantaneous, like a thunderbolt for one of them, a little 

 slower for the second, who still breathed for a few seconds, but had 

 already lost consciousness. 



The autopsy (made by M. Gallard under bad conditions, after 

 exhumation and previous autopsy by the physician of Chalonnes) 



