Answer: a pin
Unfortunately, Colin Blythe has developed progressive myopia due to his many years of forgery work; he can see objects at very close range but is unable to see five feet in front of his face. When "Big X" Bartlett finds out about Blythe's condition, he wants to prevent Colin from entering the escape tunnel. Blythe had earlier planted a pin on the floor in case anyone doubted his eyesight. Roger Bartlett, however, doesn't fall for the ruse and moments later trips Blythe. Hendley then comes to Blythe's defense by assuring Big X that he, Hendley, will take take care of Colin in the escape.