Giannotto had helped him in his experiments; there was an assistant who attended the fires. But no one followed the Duke into it unbidden.

But, as time went on, Giannotto debated with himself that he would venture. Visconti was long. What was he doing? It was an opportunity to spy. If caught, the secretary could plead anxiety as to his master's safety. Summoning his courage, Giannotto rose and crept to the unlocked door and softly pushed it back.

It opened on a flight of stairs, black marble, carpeted in gold, the high walls hung with tapestry in red.

The steps were few in number, before they twisted abruptly out of sight. Round the bend floated a thin wisp of grey smoke.

Giannotto slowly and cautiously mounted. At the bend the steps still continued, twisting again.

It was very silent, very still, only the lazy floating wreath of smoke moving. Giannotto came within sight of a door, ajar. He marvelled at it. It was thus Conrad von Schulembourg had escaped—through an unlocked door. Visconti trusted overmuch to the terror of his name.

Giannotto slowly and cautiously pushed it a little further open. It showed him the outer laboratory, a long low room of grey stone, and lit by a large window set back a man's height in the wall.

Hanging over a clear charcoal fire, burning in a pan, was an elaborate silver pot, seeming to quiver in the vapour that shimmered off the fire underneath.

Around it on the floor stood glasses, vases, jars, and goblets, glass, china, and gold.

Save this, the vault-like chamber was void of furniture; only on the stove near the window lay a pile of things, curiously mixed. They held Giannotto's eyes. They were not in the laboratory when he worked there.

A man's doublet of white satin, a scent bottle, a spray of roses, a mask, a poniard, two scarfs intertwisted, and, sparkling on an inlaid tray, a massive ring—he knew it, he had seen it on Isotta's hand—her wedding ring; all this thrown among two birds and a hound, stiff and dead.

Giannotto started a step back. Then his eyes fell on the window-seat, and even he could scarce suppress a cry. For Visconti stood there, erect and motionless, so motionless and so one with the stone beside him, Giannotto had not known him there. From head to foot he was clad in grey. In his right hand he held a pair of gloves, turquoise blue, magnificently worked in pearls, and in the other a small phial filled with a yellow, slow-moving liquid. This he held high against the light, which fell strong and cold upon his upturned face and thick, curling red hair, and Giannotto gazed, fascinated, on the gleam of his teeth as he smiled with a slow satisfaction. Giannotto had seen enough. His heart beat quickly. He drew the door to again, and crept back down the steps unobserved, gaining the outer chamber, trembling; and there for a moment fell upon his knees, as if in thanks for a most merciful escape. His thanks were not without their reason. Hardly was the secretary in his chair again, when a light footfall sounded and Visconti entered.

For one moment Giannotto thrilled with terror, but a covert glance at the Duke's face reassured him.

'I have this to give you, my lord,' he began at once. 'It was left in the Lady Isotta's prison.'

Visconti took the parchment.

'By whom left there?' he asked.

'I know not, my lord,' said Giannotto. 'Luisa brought it, but dared not leave her post.'

His own narrow escape of a moment since had tied up Giannotto's tongue.

'It will not be hard to discover,' said Visconti. 'Someone who did not bribe Luisa high enough.'

'Della Scala lives,' he read again.

'Let the Lady Isotta have it,' he said. 'It may keep her alive. It looks to me that she may die, Giannotto, of the bad air and the confinement,' and he smiled.