The other started again, nodded, and said, "That was the house."

"Now," pursued the captain, "between those two men cast away there arose
a mystery concerning the round sum of five hundred pound."

Again Tregarthen started, changing colour. Again the captain said,
"What's the matter?"

As Tregarthen only answered, "Please to go on," the captain recounted,
very tersely and plainly, the nature of Clissold's wanderings on the
barren island, as he had condensed them in his mind from the seafaring
man. Tregarthen became greatly agitated during this recital, and at
length exclaimed,--

"Clissold was the man who ruined me! I have suspected it for many a long
year, and now I know it."

"And how," said the captain, drawing his chair still closer to
Tregarthen, and clapping his hand upon his shoulder,--"how may you know
it?"

"When we were fellow-clerks," replied Tregarthen, "in that London house,
it was one of my duties to enter daily in a certain book an account of
the sums received that day by the firm, and afterward paid into the
bankers'. One memorable day,--a Wednesday, the black day of my
life,--among the sums I so entered was one of five hundred pounds."

"I begin to make it out," said the captain. "Yes?"

"It was one of Clissold's duties to copy from this entry a memorandum of