doctor and I are deadly rivals. We are rival scientists, and I was waiting for the hairy man to steal a march on him."
"But, but—how did you get in."
"I had this key," he said holding up a small key, "remember, word of honour! The man whom I have just left came up and wasn't certain whether he had to go in No. 8, that's the doctor's, or No. 6—and the one key fits both doors!"
He inserted the key which was in the lock of her door and it turned easily.
"And this is what I was waiting for—it was the best the poor devil could do."
He lifted the paper package and broke the seals. Unfolding the paper carefully he laid it on the table, revealing a teaspoonful of what looked like fine green sawdust.
"What is it?" she whispered fearfully.
Somehow she knew that she was in the presence of a big elementary danger—something gross and terrible in its primitive force.
"That," said Mr. Beale, choosing his words nicely, "that is a passable imitation of the Green Rust, or, as it is to me, the Green Terror."
"The Green Rust? What is the Green Rust—what can it do?" she asked in bewilderment.
"I hope we shall never know," he said, and in his clear eyes was a hint of terror.
CHAPTER III
PUNSONBY'S DISCHARGE AN EMPLOYEE
OLIVA CRESSWELL rose with the final despairing buzz of her alarm clock and conquered the almost irresistible temptation to close her eyes, just to see what it felt like. Her first impression was that she had had
