"If we have finished, we had better go up to the laboratory and see that the apparatus is ready. Mr. Britton is a busy man, and, as he is doing us a great service, we mustn't keep him waiting when he comes."
We ascended to the laboratory, where Polton was already busy inspecting the massively built copying camera which—with the long, steel guides on which the easel or copy-holder traveled—took up the whole length of the room on the side opposite to that occupied by the chemical bench. As I was to be inducted into the photographic art, I looked at it with more attention than I had ever done before.
"We've made some improvements since you were here last, sir," said Polton, who was delicately lubricating the steel guides. "We've fitted these steel runners instead of the blackleaded wooden ones that we used to have. And we've made two scales instead of one. Hallo! That's the downstairs bell. Shall I go sir?"
"Perhaps you'd better," said Thorndyke. "It may not be Mr. Britton, and I don't want to be caught and delayed just now."
However, it was Mr. Britton; a breezy alert-looking middle-aged man, who came in escorted by Polton and shook our hands cordially, having been previously warned of my presence. He carried a small but solid hand-bag, to which he clung tenaciously up to the very moment when its contents were required for use.
"So that is the camera," said he, running an
