When we were in the presence of new phenomena (writes Thury) there was only one alternative: First, either to reject, in the name of common sense and of the results acquired by science, all the pretended phenomena of tables as so many childish sports unworthy of taking up the time of the true scientist or scholar, since, on the very face of it, their absurdity is evident; in short, to let the matter drop by refusing to give it serious attention. Or, second, to make a determined examination of it at whatever cost, to study the fact in its details in order to lay fully open all the sources of illusion by which the public is duped, separate the true from the false, and throw a strong light on all aspects of the phenomenon, physical, physiological, and psychological, in order that the matter may be so superabundantly clear and evident that no further excuse for doubt may remain. Superfluous to say, the last method is the one adopted by Thury (as it was by Gasparin). He considers it to be the only suitable, efficient, and legitimate method. Darkness saps the strength of science. Its strongest hold lies in bringing everything out into the full light of day. Here, then, lies the question: In these curious phenomena of the tables, is the explanation so clear that you can lay a finger on the causes of illusion and clearly show that there is in them no new and unknown element at work? I do not think (replies the Genevan professor) that we have attained to that degree of evidence. I wish only one proof, the explanation of what has already been attempted. If, then, it is well established that the common explanation is not self-evident, in the eyes of all intelligent and sensible men, there remains a task to do, a duty owed to science,--that of throwing full light upon the phenomenon in question; and this task cannot be exchanged for the easier one of treating with irony or disdain those who have gone astray in the path that Science refused to illuminate. The savants are, however, excusable for not going too quick (let us admit with Thury). What! a perturbative force lurking, by the hypothesis, in the human organism sufficiently powerful to lift tables, and which yet had never produced the slightest derangement in the thousands of experiments that physicists are daily making in their laboratories! Their balances, responsive to the weight of a tenth of a milligram, their pendulums whose oscillations take place with mathematical regularity, had never felt the slightest disturbing effect of these forces, whose source is there present wherever there is a man and a volition! Now, it is the ardent wish of the physicist that the experiment shall always exactly tally the forecasts of theory. Must he then admit an unknown disturbing force?