But indeed the evidence, in one form and another, has been crudely before the human race from remote antiquity; only it has been treated in ways more or less obfuscated by superstition. The same sort of occurrences as were known to Virgil, and to many another seer--the same sort of experiences as are found by folk-lore students, not only in history but in every part of the earth to-day--are happening now in a scientific age, and sometimes under scientific scrutiny. Hence it is that from the scientific point of view progress is at length being made; and any one with a real desire to know the truth need not lack evidence, if he will first read the records with an open mind, and then bide his time and be patient till an opportunity for first-hand critical observation is vouchsafed him. The opportunity may occur at any time: the readiness is all. Really clinching evidence in such a case is never in the past; a _prima facie_ case for investigation is established by the records, but real conviction must be attained by first-hand experience in the present. The things to be investigated are either true or false. If false, pertinacious inquiry will reveal their falsity. If true, they are profoundly important. For there are no half-truths in Nature; every smallest new departure has portentous consequences; our eyes must open slowly, or we should be overwhelmed. I once likened the feeling of physical investigators in the year 1889 to that of a boy who had long been strumming on the keyboard of a deserted organ into which an unseen power had begun to blow a vivifying breath.[40] That was at the beginning of the series of revolutionary discoveries about radiation and the nature of matter which have since resounded through the world. And now once more the touch of a finger elicits a responsive note, and again the boy hesitates, half delighted, half affrighted, at the chords which it would seem he can now summon forth almost at will. [Footnote 40: _Modern Views of Electricity_, p. 408 of third and current edition.] CHAPTER XVI OUTLOOK ON THE UNIVERSE