"Wait a bit. Don't you remember old Peters making it once by boiling sulphur with tallow? And he told us you get a more steady flow of gas that way. We've probably got all we want on the premises. But how are you going to get it into the room?"
"We'll have to find a way. Let's go and investigate."
Inquiry of Mrs. Trenchard elicited the information that her store cupboard ran along the whole length of the room in which Smail had made himself at home. The wall between them was rather thick, but it would certainly not be impossible to pierce a hole in it.
"Splendid!" said Eves. "We can make the gas in the store cupboard, and pass it into the room through one of our tubes. Of course, we'll have to lock the man in."
"The gas won't drive him out of the window," said Templeton. "In fact, if he keeps that open the smell will never be strong enough."
"You may be sure the window won't be open. A fellow of that sort revels in fug. No doubt he'll take an afternoon nap to-morrow. That'll be our time. He'll wake up choking, and if I know my man he'll make a dash for the window and tumble out into the open—by the way, I suppose the gas won't actually poison him?"
"No; the worst effect, I believe, is sickness and dizziness. We had better start boring our hole to-night, when he's asleep. If we're careful he won't hear us."
"We must get Mother Trenchard to take out her stores. Shall we tell her why?"
"Better not. I'll just say we want to try an experiment."
Mrs. Trenchard somewhat reluctantly agreed to remove her stores for a short time. From her they obtained a quantity of tallow and a few sticks of brimstone, and in the privacy of their bedroom they broke up and pulverised one of the sticks, and boiled a little of the sulphur powder with tallow in a tin.