They persisted , thinking they could force their way through it , began to feel dizzy , collapsed , and eventually suffocated .
Reaching their work level ( at 25 fathoms ) the first two encountered the bad air .
two persisted , thinking two could force two 's way through it , began to feel dizzy , collapsed , and eventually suffocated .
Reaching their work level ( at 25 fathoms ) the first two encountered the bad air .