At five o’clock Jack was at the chemist’s and received his package. On opening it he found the ozak in two four-ounce, glass-stoppered bottles, and these he put in his pocket.

“Will you give me three spray syringes, as large a size as you have, rubber, glass, and metal. I’m not sure but this stuff will attack one or other of them, and I don’t want to spend the rest of my life running down to your shop.”

Getting the syringes, he jumped into his cab, and was driven to the Professor’s.

“You may call for me at ten,” he said to the cabman.

There were three others besides the Professor and himself, and they were all interested in learning the latest scientific news from New York and London.

It was a quarter past ten when the company separated. Lermontoff stepped into his cab, and the driver went rattling up the street. In all the talk the Prince had said nothing of his own discovery, and now when he found himself alone his mind reverted to the material in his pocket, and he was glad the cabman was galloping his horse, that he might be the sooner in his workshop. Suddenly he noticed that they were dashing down a street which ended at the river.

“I say,” he cried to the driver, “you’ve taken the wrong turning. This is a blind street. There’s neither quay nor bridge down here. Turn back.”

“I see that now,” said the driver over his shoulder. “I’ll turn round at the end where it is wider.”

He did turn, but instead of coming up the street again, dashed through an open archway which led into the courtyard of a large building fronting the Neva. The moment the carriage was inside, the gates clanged shut.

“Now, what in the name of Saint Peter do you mean by this?” demanded the Prince angrily.