To this Zorzi answered nothing, for he was glad not to be questioned further about what had happened.  Presently Beroviero settled to his work with his usual concentration.  For many months he had been experimenting in the making of fine red glass of a certain tone, of which he had brought home a small fragment from one of his journeys.  Hitherto he had failed in every attempt.  He had tried one mixture after another, and had produced a score of different specimens, but not one of them had that marvellous light in it, like sunshine striking through bright blood, which he was striving to obtain.  It was nearly three weeks since his small furnace had been allowed to go out, and by this time he alone knew what the glowing pots contained, for he wrote down very carefully what he did and in characters which he believed no one could understand but himself.

As usual every morning, he proceeded to make trial of the materials fused in the night.  The furnace, though not large, held three crucibles, before each of which was the opening, still called by the Italian name ‘bocca,’ through which the materials are put into the pots to melt into glass, and by which the melted glass is taken out on the end of the blow-pipe, or in a copper ladle, when it is to be tested by casting it.  The furnace was arched from end to end, and about the height of a tall man; the working end was like a round oven with three glowing openings; the straight part, some twenty feet long, contained the annealing oven through which the finished pieces were made to move slowly, on iron lier-pans, during many hours, till the glass had passed from extreme heat almost to the temperature of the air.  The most delicate vessels ever produced in Murano have all been made in single furnaces, the materials being melted, converted into glass and finally annealed, by one fire.  At least one old furnace is standing and still in use, which has existed for centuries, and those made nowadays are substantially like it in every important respect.

Zorzi stood holding a long-handled copper ladle, ready to take out a specimen of the glass containing the ingredients most lately added.  A few steps from the furnace a thick and smooth plate of iron was placed on a heavy wooden table, and upon this the liquid glass was to be poured out to cool.

“It must be time,” said Beroviero, “unless the boys forgot to turn the sand-glass at one of the watches.  The hour is all but run out, and it must be the twelfth since I put in the materials.”

“I turned it myself, an hour after midnight,” said Zorzi, “and also the next time, when it was dawn.  It runs three hours.  Judging by the time of sunrise it is running right.”

“Then make the trial.”

Beroviero stood opposite Zorzi, his face pale with heat and excitement, his fiery eyes reflecting the fierce light from the ‘bocca’ as he bent down to watch the copper ladle go in.  Zorzi had wrapped a cloth round his right hand, against the heat, and he thrust the great spoon through the round orifice.  Though it was the hundredth time of testing, the old man watched his movements with intensest interest.