PREFACE.

...interpreted by Professor Henry. And here, a word might be said regarding the harmful influence still exerted by "authority" in science. The claims made by the highest authorities—that no detectable echo ever comes from clear air—were so definitive that my mind, for a time, refused to even consider the idea. This reliance on authority caused me to stray from the truth for weeks and to seek answers among delusions.

On the day our observations at the South Foreland A headland on the Kent coast of England, where many of these sound and signaling experiments were conducted. began, I heard the echoes. They puzzled me. I heard them again and again, and I listened to the explanations offered by some clever people at the Foreland. They called them an "ocean echo"; this is the exact terminology now used by Professor Henry. They said they were echoes "from the crests and slopes of the waves"; these are the very words of the hypothesis he now supports. Through part of May, the whole of June, and nearly the whole of July 1873, I was occupied with these echoes. One of the theories I passed through during that time—one of the solutions I weighed in the balance and found wanting—was identical to the one Professor Henry now offers for acceptance.

But even though it led me off the proper track, should I say that authority in science is harmful? Not without some qualification. It is not only harmful, but deadly, when it intimidates the intellect into fearing to question it. However, the authority that deserves our respect—which compels us to test and disprove all its supports before we accept a conclusion opposed to it—is not entirely harmful. On the contrary, the discipline it imposes can be beneficial in the highest degree original: "salutary", even though those efforts may end, as in the present case, in the downfall of that authority. The truth established in this way is made firmer by our struggles to...