The stress exerted by the girl is very feeble, because, on the one hand, she has the lever arm to herself, and, on the other, the action upon her lever arm is a simple traction.

When she feels that the pressure exerted is great enough, she directs the two men to exert a vertical stress strong enough to cause the stick to descend.

They then imagine that they are exerting a VERTICAL stress, while in reality their stresses are HORIZONTAL and tend to keep the stick in a vertical position in order to react against the pressure exerted at the lower end of the stick.
There is evidently a certain vertical component that tends to cause the stick to descend, but the lateral pressure produces a sufficient friction between the hand and the stick to support this vertical force without difficulty.

Mr.Perry performed the experiment by placing himself upon a spring balance and assuming the role of the girl, with two very strong men as adversaries.

All the efforts made to cause the stick to slide in the open hand failed, and the excess of weight due to the vertical force always remained less than twenty-five pounds, despite the very determined and sincere stresses of the two men, who, unbeknown to themselves, were exerting their strength in a HORIZONTAL direction.
In the experiment represented in Fig.