Henri chuckled.

"You are not an expert fisherman then, Pierre," he answered. "Still, one can land a very good fish with a pole and string; I have done it scores of times. But professional fishermen have a bit of silk-gut to connect the hook with the line. Not only is it very strong, but it is invisible when under water. Most of the silk-gut is made in Italy or Spain, the Spaniards surpassing all others at manufacturing it. Valencia is the chief centre for the industry."

"And how is it made? Spun from silk fibres?"

"Not at all. You remember how, before the silkworm begins to spin, the viscid secretion is stored in the two long ducts at each side of the little creature's body. It is that material which it unites into a single thread in the spinaret, you know. Well, before the worm has a chance to spin, it is put into vinegar and this jellied silk is extracted. It is first soaked in cold water and afterward in a caustic solution so that its outer covering can be loosened and taken off. Then the yellowish gum is dried in a shady place and bleached white by means of sulphur fumes. You can see that it is expensive because so many silkworms must be sacrificed, and because the thread produced is so small. Why, I have read that it takes as many as twenty or thirty thousand strings to make a pound."

Pierre gasped.

"No wonder I don't use silk-gut on my fish-line!" he exclaimed.

In the meantime the boys were passing on amid the stifling atmosphere and whirling machines.

Suddenly the noon whistle blew and the busy wheels of the mill became still.

Pierre and Henri were only too glad to emerge with the others from the close, steamy air of the factory into the coolness of the outdoor world. Down by the river's bank they unpacked their luncheon, a royal feast, for Madame Bretton had sent enough food for both hungry boys. They were in jubilant spirits.

"If I had a line with some silk-gut on it I might perhaps land a trout," said Pierre mischievously.