Yet his bulldog mind would not let go of the problem. Presently he had
found a new avenue of approach to it. If Rivière had travelled away from
Paris on the evening of the 15th, probably he stayed that night or the
next day at some hotel. There he would have to fill in his name, etc.,
in the hotel register according to the strict requirements of the French
law.

Advertise in the papers for one John Rivière from Paris, age
thirty-seven, staying at a hotel in the provinces on the 15th or 16th.
Offer a reward for information. The average Frenchman is very keen on
money; without a doubt he would answer the advertisement if he knew
anything of John Rivière. Advertise in _Le Petit Journal_, _Le Petit
Parisien_ and a few other dailies which cover France from end to end, as
no English or American journals do in their respective countries.

That was the right solution!

Larssen did not pay the cheque for £20,000 into his bank. He was after
big game, and a mere £20,000 was a jack-rabbit. It would be safer, he
felt, to let it lie amongst his secret papers.

When Sylvester, his private secretary, arrived by the afternoon train
from London, Lars Larssen placed him in touch with only so much of the
situation as he considered desirable. This was little. Sylvester was to
stay in Paris while the shipowner went on to Monte Carlo. If the various
advertisements brought a reply, Sylvester was to hunt out John Rivière
in whatever part of France he might be, and then communicate with Lars
Larssen for further orders.