Strange way of verifying and establishing the results of experiments! You begin by changing the conditions under which they are produced. You might as well say to the man who has seen the harvesting of barley in Upper Egypt in January, "I will believe it when I see it done before my eyes in Bourgogne." One can understand, of course, how an unreasonable and troublesome fastidiousness might be shown regarding travellers' tales. But scientific experiments are of another character. In the presence of facts so evident, it is almost incredible that they wish to impose upon us instruments, needles, and mechanical devices. The idea of introducing _becauses_ and _therefores_ into an investigation in which the real nature of the acting force is a mystery to all the world! Polemical essays are not scientific studies. In general, they are the direct opposite. When persons who have seen nothing, who have not devoted any considerable portion of their energy and time to experimentation, who have perhaps been present only at some ridiculous rotations of centre-tables, take their pen in hand for the purpose of exposing theories or giving lofty reprimands to experimenters, I do not look at them in the light of scientific students. I am convinced that a man never really studies that which he declares _a priori_ to have no sense in it. If attacks are studies, there is no lack of them, and (I may add) never will be. At the time when the Academy of Medicine buried the report of M. Husson and published what everybody in Europe persisted in calling a refusal to examine, there was issued every morning a paper against magnetism; every morning some new writer vociferated that the partisans of magnetism were imbeciles, and proposed an explanatory system of his own. If you call that making a study, then I grant that they have studied table-turnings, for there certainly has been no dearth of insults and of theories about these phenomena. They have received every attention, except that no one was willing to inspect, experiment, listen, and read. Twice, a month apart, the Institute has announced (without protest from anybody whatever) to the students of table-turnings that it was shelving papers relating to that topic; that it was not obliged to occupy itself with nonsense; that there was a place in its archives for lucubrations of that kind; namely, the place to which were consigned papers on perpetual motion.