"Now, the next thing we want to know is, does gravity act in all directions?"
"Yes; and the attraction of one body for another is in proportion to its mass—that is to say, if two bodies, one weighing one and the other two pounds, should be hung near each other, the heavy object would pull the lighter one twice the distance it would itself move."
"Do you mean to say that everything on earth attracts everything else? I thought it was only the earth that had the power to attract."
"The earth is no different from any other object in that particular, but on account of its immense size everything goes toward it and its motion toward the small object is not noticed."
"Is there any way that such a statement could be proved?"
"I suggest one plan: select two walls, close together, or two tall trees, and run a wire across, as I show in the sketch (Fig. 32). From that cross wire, A, suspend three objects by cords, B, C, D. The cord B is exactly midway between the two walls, and the other cords C, D, and so attached that the objects at their lower ends hang close to the walls. It will be found that the cords C, D are farther apart at their lower ends than at the upper ends, and that the cord B is exactly plumb, as it is affected equally by the attraction of the opposite walls."
Fig. 34. Gravitational pull.
The new raft attachment was completed, and Harry made the suggestion that it ought to be put to a practical test, and that a good place to do this would be below the cataract, where it was wide and deep enough to float.
The drill was affected for attaching the sections, as shown in the drawing (Fig. 35), in which A represents the section under the axles, and B, C the two side sections, attached at their inner edges to the ends of the axles, and with the posts D serving as braces.