The two men walked down the passage towards the river. Here also the arrangement was the same as at Ferriby, and they remained only long enough for Willis to point out to the Frenchman how the loading apparatus was worked.
“Well,” said the former, as they returned to the office, “that’s not so bad for one day. I suppose it’s all we can do here. If we can learn as much at that distillery we shall soon have all we want.”
Laroche pointed to a chair.
“Sit down a moment,” he invited. “I have been thinking over that plan we discussed in the train, of searching the distillery at night, and I don’t like it. There are too many people about, and we are nearly certain to be seen. It’s quite different from working a place like this.”
“Quite,” Willis answered rather testily. “I don’t like it either, but what can we do?”
“I’ll tell you what I should do.” Laroche leaned forward and checked his points on his fingers. “That lorry had just been unloaded. It’s empty now, and if our theory is correct it will be taken to the distillery tomorrow and left there over-night to be filled up again. Isn’t that so?”
Willis nodded impatiently and the other went on:
“Now, it is clear that no one can fill up that tank without leaving finger-prints on the pipe connections in that secret box. Suppose we clean those surfaces now, and suppose we come back here the night after tomorrow, before the man here unloads, we could get the prints of the person who filled up in the distillery.”
“Well,” Willis asked sharply, “and how would that help us?”
“This way. Tomorrow you will be an English distiller with a forest you could get cheap near your works. You have an idea of running your stills on wood fires. You naturally call to see how M. Raymond does it, and you get shown over his works. You have prepared a plan of your proposals. You hand it to him when he can’t put it down on a desk. He holds it between his fingers and thumb, and eventually returns it to you. You go home and use powder. You have his finger-prints. You compare the two sets.”