Two things seemed pretty apparent to me.

One was, that in order to be a pilot a man had got to learn more than any one man ought to be allowed to know; and the other was, that he must learn it all over again in a different way every twenty-four hours.
That night we had the watch until twelve.

Now it was an ancient river custom for the two pilots to chat a bit when the watch changed.

While the relieving pilot put on his gloves and lit his cigar, his partner, the retiring pilot, would say something like this-- 'I judge the upper bar is making down a little at Hale's Point; had quarter twain with the lower lead and mark twain {footnote [Two fathoms.
'Quarter twain' is two-and-a-quarter fathoms, thirteen-and-a-half feet.
'Mark three' is three fathoms.]} with the other.' 'Yes, I thought it was making down a little, last trip.

Meet any boats ?' 'Met one abreast the head of 21, but she was away over hugging the bar, and I couldn't make her out entirely.