“Mr. Parks,” said Nick, stepping forward, “I promised that within the hour I would bring you face to face with the coward and villain who stabbed your wife.
“I will keep my word. Behold Doc Helstone!”
With a sudden movement Nick raised a mirror which he had held concealed behind him and thrust it before Parks’ face.
Parks leaped back as if a thunderbolt had struck him.
In that mirror he saw his face wearing the exact disguise which he had led his gang of thieves to believe was the real countenance of Doc Helstone.
There was the light-brown beard parted in the middle, there were the gray eyes and light eyebrows, and rather pale skin.
“Surprised, are you?” said Nick. “Why, it was the simplest thing in the world.
“When I made your face up half an hour ago I used a false beard colored with a substance which is black when it is moist, but light-brown when it is dry.
“Your eyebrows were colored with the same substance. It dries very quickly. Five minutes after I showed you the dark face in the glass you had begun to look like Doc Helstone. Every black line was fading into brown.
“The tint which I used on your skin acts the same way. It turns from a tan color to a pale flesh tint by simply being exposed to the air.