"Does he know its object?" asked David.
"No, there's been no chance to tell him."
"Why is he interested, then?" asked David. "Has his commercial instinct been aroused?"
"Oh, I think not," said the inventor, "I've not spoken to him about that part of it, only told him a great chance was his if he became interested in the machine."
"Someone's ringing the bell. Run down, Peter," said Mrs. Procter.
Peter went down and returned at once with a note.
"A man with brass buttons brought it," he said. "It's for father."
Mr. Procter tore open the letter.
"Well, that's decent of John Massey to let me know," he said. "He's ill and will be unable to come here tomorrow."
"Yes, very decent for old John Massey," said David. "Well, I must be off. And we'll come again soon, if we may."