‘Hallo? Is that M. Boirac’s?--Is M. Boirac at home?--About seven o’clock? Ah, thank you. I’ll ring up again later.--No, don’t mind. It’s of no consequence.’ He replaced the receiver. ‘He’s crossing by the 11.00 from Charing Cross, and will be home about seven. If you were to call about half-past six, which is the hour at which he usually returns, your visit would not be suspicious, and you could have a chat with François.’ ‘I shall do that, monsieur,’ and with a bow the detective withdrew. The clocks had just finished chiming the half-hour after six when Lefarge presented himself at the house in the Avenue de l’Alma. François opened the door. ‘Good-evening, M. François. Is M. Boirac at home?’ ‘Not yet, monsieur. We expect him in about half an hour. Will you come in and wait?’ Lefarge seemed to consider, and then,-- ‘Thanks. I think I will.’ The butler preceded him to the small sitting-room into which he had shown the two detectives on their first call. ‘I heard at the Sûreté that M. Boirac had gone to London to identify the body. You don’t know, I suppose, if he was able to do so?’ ‘No, monsieur. I knew he had gone to London, but I did not know for what purpose.’ The detective settled himself in a comfortable chair and took out a cigarette case. ‘Try one of these. They’re special Brazilian cigarettes. I suppose we may smoke here?’ ‘Certainly, monsieur. I thank you.’ ‘It’s a long way over from London. I don’t envy Monsieur his journey. You’ve been, I suppose, monsieur?’ ‘Twice, monsieur.’ ‘Once is all right to see the place, but after that--no, thank you. But I suppose M. Boirac is used to it? They say you can get used to anything.’ ‘I should think he must be. He travels a lot. London, Brussels, Berlin, Vienna--he had been at them all to my knowledge in the last two years.’ ‘I’m glad it’s he and not I. But I should think this unhappy event would take away his love for travelling. I should imagine he would want to stay quiet in his own home and see no one. What do you think, M. François?’ ‘Well, he hasn’t anyway, or else he can’t help himself. This is the second journey he’s made since then.’ ‘You surprise me. Or rather, no, you don’t. I suppose we shouldn’t be talking about what doesn’t concern us, but I would be willing to lay a napoleon I could tell you where the first journey was to and what it was for. It was to see the Wilson Test. Am I not right?’ ‘The Wilson Test, monsieur? What is that?’ ‘Have you never heard of the Wilson Test? Wilson is the head of a great firm of English pump manufacturers, and each year a reward of over 10,000 francs is offered by them for any pump that can throw more water than theirs. A test is held every year, and the last one took place on Wednesday. M. Boirac would naturally be interested, being head of a pump manufactory himself. He would go to the Test.’