Stanley Hopkins drew from his pocket a drab-covered notebook. The outside was rough and worn, the leaves discoloured. On the first page were written the initials “ J. H. N. ” and the date “ 1883 .” Holmes laid it on the table and examined it in his minute way, while Hopkins and I gazed over each shoulder. On the second page were the printed letters “ C. P. R. ,” and then came several sheets of numbers. Another heading was “Argentine,” another “Costa Rica,” and another “San Paulo,” each with pages of signs and figures after it.

“What do you make of these?” asked Holmes.

“They appear to be lists of Stock Exchange securities. I thought that ‘ J. H. N. ’ were the initials of a broker, and that ‘ C. P. R. ’ may have been his client.”