The result of this experiment (of June 4, 1853) showed that the force which tends to make the table turn is in the individuals and not in the ground. For the force exerted upon the table tends to draw along the platform with it. If, then, the platform remains motionless, it must be that an equal and contrary force is exerted by the operators. It is therefore in them that the base of the seat of the force resides. If, on the contrary, this force had emanated, wholly or in large part, from the ground, if it had been a force directly telluric, the platform would have turned, the effort which the table exerted upon it being no longer counterbalanced by an equal reaction proceeding from the individuals.
_Conditions of the Production and Action of the Force._--I have said that the conditions for the production of the force are little known. In the absence of precise laws, I shall present what has been verified in a greater or less degree in the case of the three following points:
_a._ Conditions of action relative to the operators.
_b._ Conditions relative to the objects to be moved.
_c._ Conditions relative to the mode of action of the operators upon the objects to be moved.
THE WILL. The first and the most indispensable condition, according to M. Gasparin, is the will of the operator. "Without the will," he says, "we obtain nothing; we might sit there in chain twenty-four hours in succession without getting the slightest movement." Farther on, the author speaks, it is true, of unexpected movements different from those which the will prescribes; but it is evident that he is referring to a necessary combination of prescribed movements and external resistances, the effective movements being the _resultant_ of those that have been willed and of forces of resistance developed in external objects. In short, the will is always the prime mover and originator.
Nothing, it is true, in the experiments at Valleyres gave any authority for believing that it could be otherwise than this. But it is also certain that this purely negative result, or provisional generalization, deduced from a limited number of experiments,--cannot invalidate the results of experiments inconsistent with those, in case such should exist. In other words, the will may ordinarily be necessary, without always being so. Similarly, contact is ordinarily necessary, and _always_ has been so with a large number of operators, without, however, giving them the right to conclude that contact is the indispensable condition of the phenomenon, and that the different results obtained at Valleyres were only illusions or error.