‘In other words, that you may bring the centre of gravity over the foot on which you are standing. The centre of gravity moves as your arms move. If you feeling yourself falling towards the left, you throw out your right arm, and that brings the centre of weight more towards the right side. The centre of gravity is but a point; and while you keep that point supported, you may stand upon a point, or upon a rope, or upon anything else. That is how the rope-dancers manage. They usually have a pole, weighted at each end with lead. The man and the pole form, practically, but one body, and have but one centre of gravity; therefore, by moving the pole a very little the performer can easily throw more weight to one side or the other as required, and so bring the centre of gravity directly over the rope.
‘It requires time and practice to become a good rope-dancer; more than it is worth, perhaps. But you can make a good balancer with very little trouble.
‘Take a common wine-bottle; fit a short cork to it, and stick a needle through the cork, so that the point may project upwards. That must be done before you put the cork into the bottle; otherwise you would have to get into the bottle to do it. The use of the bottle is merely as a stand. I wish the bottle were never put to any worse use than that.
‘Take another cork and stick a long pin through it, so that the point may project half an inch or so downwards, into the sides of this second cork stick two forks in a slanting direction, handles downwards. Now with a little patience you will be able to place the point of the pin upon the point of the needle; and once there, there it will remain balanced, swaying about and perhaps turning round a little, but without falling off. The weight is here in the forks, and the centre of gravity low down, between the two handles. The handles, therefore, being free to move, adjust themselves, so that the centre of gravity is supported, and that is all that is required.’
‘Our Jack was carrying a bucket of water the other day, and the handle came off. The bucket dropped down on one side, and he fell over on the other. What made him fall, sir, when the bucket fell?’
‘Jack was carrying the bucket in his left hand, I suppose, and leaning over to the right, stretching out the right arm to keep the balance. When the weight of the bucket was suddenly removed, the centre of gravity was raised, and thrown at the same time to the opposite side. As long as the heavy bucket formed part of him (as I may say), the centre of gravity was nearer the ground; but when it fell, Jack’s centre was raised, and he overbalanced. The lower the centre of gravity is in any body, the more firmly that body will stand; and the higher it is up, the more likely it will be to topple over. I saw some of you walking on the top of a wall the other day, and you had some difficulty in balancing yourselves. Others crept on their hands and knees; they required no balancing, because their centre of gravity was lowered, and their base of support extended.’
‘Yes, I understand that. But you said just now that a man could be more easily balanced at the top of a long pole than on a short one; or a donkey (with four legs) upon a high ladder more easily than on a lower one. How can that be?’
‘It sounds like a contradiction, but it is true, nevertheless. Try it. Not with a donkey, but with this stick, which has a heavy knob at one end. With the knob downwards, resting on the palm of your hand, you can scarcely balance the stick for a moment; but with the knob upwards there is comparatively little difficulty.’
‘It is so, certainly; but I don’t understand why.’