This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
A local junk dealer, who was also known as the "strongest man in town,"' used to mystify the folks by opening a bottle, apparently with a stroke of his index finger. His audience saw his index finger strike the stopper, but did not see the knuckle of his second finger strike the eccentric at the point A, as shown in the sketch, causing it to fly up while his index finger B assisted the stopper out of the bottle mouth.
When trying the trick, it is best to select a bottle with a loose stopper, or else wear a glove, as the gentleman who demonstrated the trick had hands of the hard and horny type. - Contributed by James M. Kane, Doyles-town, Pa.
Ill: In Striking the Bottle Cork, the Knuckle of the Second Finger Loosens the Wire Lock