Giovanni turned and watched him.
"You are really very cautions," he said.

"Do you always lock the door when you go out ?" "Always," answered Zorzi, shouldering his blow-pipe.
They crossed the little garden and entered the passage that led to the main furnace rooms.

In the first they entered, eight or ten men and youths, masters and apprentices, were at work.

The place was higher and far more spacious than the laboratory, the furnace was broader and taller and had four mouths instead of three.

The sunlight streamed through a window high above the floor and fell upon the arched back of the annealing oven, the window being so placed that the sun could never shine upon the working end and dazzle the workmen.
When Giovanni and Zorzi entered, the men were working in silence.