“But what are these prescriptions?” asked the monk, puzzled.
“You would know by this time,” said the Paduan grimly, “if that flame-crested imp of yours, Padraig, had been the one to experiment. By following the directions on this bit of vellum he might have blown us all into the other world. Luckily only three of these formulæ are of that nature. The others are quite safe for your young disciples to play with. But these we will keep to ourselves.” He laid a stained brownish piece of sheepskin apart from the others and two smaller ones beside it. “These are directions for the manufacture of aqua regia, Spanish gold, and something which Archiater called Apples of Sodom. Of a certainty they are fruit of the Tree of Knowledge, those apples.”
Brother Basil had lost color. This really was a trifle too near necromancy to be pleasant. Spanish gold was a Saracen invention, said to be made of most unholy materials, and he had heard of a wizard being carried bodily off on the wind after dealing in the others.
“We will carry on our experiments,” Tomaso continued, “in the cellars of my tower, if you please. The young ones will be only too glad to be rid of us. If any one meddled here we should risk all we have done and the lives of our pupils. If we make any blunders working by ourselves—well—I sometimes think that I have lived a long time already.”
The disciples were too well trained to ask any questions, but they were somewhat mystified by the proceedings which ensued. An underground chamber straitly walled in with masonry was fitted up, and the smells that clung to the garments of Brother Basil when he emerged were more like brimstone than anything else. Tomaso was never seen at all. Meanwhile the newly discovered formulæ for glass and enamel work had been turned over to the workers in the glass-house, with permission to buy whatever material was needed. Padraig and Guy went to London, and came back with precious packets of rare gums, dyes, minerals, oils and salts, not to be found or made at the Abbey.
Meanwhile the monk and the physician worked with absorbed intentness at their crucibles and stills. There was a slight explosion one evening, and a country lout of the neighborhood told of it. Next day a neighboring farmer ventured to ask Padraig what was going on in the ruined tower.
“Why,” said Padraig soberly, “we are raising a brood of hobgoblins for the King. Did ye not know?”
The making of sulphuric acid, nitric acid and their compounds would have been risky business in any age, with the primitive apparatus that the two investigators had. They were furthermore made cautious by the fact that they did not know what might happen if they made the least error. It was midnight after a long and nerve-racking day when they became satisfied that they had the secrets of at least three perilous mixtures in the hollow of their hands.
“I think the King would give seven such chests as the one he sent, if he knew what we know,” said Brother Basil musingly.
“He has the value of that chest already, in the rose window and the great window, the monstrance, the chalice and the cups,” Tomaso answered, his sense of money values undimmed. “They are as good in their way as Limoges itself can do.”