The knock was answered by a smartly-dressed maid with a crafty yet heedless air. On Rachel's inquiring for Mr. Nicholas Hart, the girl eyed them with sharp suspicion.
"Mr. Hart don't ever see anyone," she said.
"He once showed my grandfather a great kindness," Rachel explained, "and I thought perhaps he might remember--"
"He don't remember much," interrupted the other; "but I suppose you can go along up," she admitted, after a further scrutiny of the pair from whom, it was clear, there was nothing to fear. "He remembers faces sometimes; you'll have to climb the stairs though," she added maliciously.
Rachel helped her grandfather up the three flights of stairs and the servant rapped on the attic door.
"Come in," piped a voice which sounded like the note of a cracked flute. And old David and Rachel entered.
The attic was wide and sunny and in the recess of a gable window stood a very little old man with a face fair and pink as a child's and with a skull cap on the back of his white head. He turned with one delicate hand resting on the barrel of a microscope. On perceiving the servant his eyes grew round with fury.
"Get out of here!" he shrilled, and, ignoring the strangers, he flew straight at the maid, skipping over the floor with remarkable briskness, his coat-tails moving like the wings of a maddened bird. The girl retreated with a laugh.
Old David presented his letter. In the presence of his host, who was as airy and, seemingly as fragile-lived as a figure traced upon a window-pane of a frosty morning, old David appeared endowed with the sturdiness of youth. "Years ago when I was a paintin' of cars," he began; but Nicholas Hart sent the letter, from which he had not removed the envelope, whirling across the floor.
"Cars," he cried, "run on wheels, but look at these wings,--" and with a finger shaking with excitement he pointed to the microscope. "Don't they beat all the wheels in creation?" he demanded.
In answer to his gesture, old David peeped timidly into the instrument; then he straightened himself and the face which he turned toward the other expressed a world of simple wonderment.
"Eh, what did I tell you?" exclaimed Nicholas exultingly. "And look here! and here!" he cried, placing one slide after another under the lens.