At that instant there came a rap on the door. Washington answered it.
"Yas sir, Perfesser Henderson done lib here," he replied, in answer to a question from some one. "But he am bery busy jest at de present occasioness an' he'll be most extremely discommodated if yo' obtrude yo' presence on him at de conglomeration ob de statutory limitations, which am to say right now. Come again!"
"It's the same old Washington!" said someone outside, laughing heartily. "Just you tell the professor we want to see him most particular."
At the sound of the voice the professor started and Mark and Jack wondered where they had heard it before.
"Show the gentlemen in, Washington," called the inventor.
"Dere's two ob 'em," objected the colored man.
"Show them both in, then."
Washington opened the door of the cabin, and in came two men, who seemed much amused over something.
"What can I do for you?" asked the professor, in rather a sharp voice.
"He don't know us either, Tom," remarked the taller of the two.