Adjoining the dial is a thermometer, which indicated the atmosphere to be eighty-two degrees Fahrenheit.
Accidents occur in the caisson, in spite of all precautions. A short time before my visit, a small stone caught in the pipe of the siphon, and one of the workmen came very near losing his arm while attempting to pull it out. His hand was drawn into the pipe, as if by a powerful magnet. The man was thrown upon his face by the great power of the atmosphere, and at the same time his arm was drawn up the pipe: had it not been for four of his comrades instantly pulling his arm down, the limb would have been torn from his shoulder. He received severe injuries, and is not likely to be so careless again. The skin of the arm looked as if a quantity of boiling oil had been poured over it, and it soon became blistered from his shoulder downward.
After a stay of nearly an hour, the party proceeded to return once more to terra firma. We entered the lock, as on making the descent, through the small iron door; then the compressed air was allowed to escape until the pressure of the air was equal to that of the atmosphere outside.
CHANGE OF ATMOSPHERE.—THE JAMS.
While this was going on, a peculiar sensation was experienced, but it was not as disagreeable as that of making the descent. It seemed as though there was a rush of water through the ears, and we were diving. Ascending to the top of the caisson occupied about ten minutes, as the physician in attendance recommends that the change from the high pressure should not be made rapidly. We were all glad to breathe the pure air and enjoy daylight again. Several of the workmen stated that nearly every day some of them suffered from the work below, and said one,—
“We have all had the jams.”
“What are the jams?” said I.
“Well,” said another, “they ain’t the jim-jams, brought on by drink, for we dare not take much, but a feeling like the flesh a tearin’ off of our bones.”
“We have the cramps in our legs, body, arms, and chest,” said another, “and at times it causes us so great pain that we cannot work; we do not notice anything amiss until we have been out of the caisson for some hours, sometimes not until the next day. These ‘jams,’ as we call them, go away as quickly as they come, but sometimes return after another visit to the caisson.”