"Oh no; Jack is a very harmless fellow," he answered.  "More than once, when it has not been blowing as hard as it does now, before I was out of my apprenticeship, I and others have chased Jack about the rigging, and caught him too.  When near, he seems to have a very dull, pale light.  I and another fellow determined to have him.  At last I clutched him.  I felt that I had got something clammy, as it were, which stung my skin like a handful of thin jelly-fish.  I brought him down on deck, and clapped him into a box.  In the morning I could feel that there was something in the box, but all the light was gone, and the box hadn't been opened long before the thing, whatever it was, was gone too."