“This spectrum is of the type known in spectroscopy as a line-spectrum. Its appearance is that of a group of bright lines on a dark background, indicating that the radiation divides itself between a number of clearly defined frequencies, and that there is no radiation in between. Before Bohr's explanation appeared, these frequencies had been supposed to belong to some sort of vibration taking place in the hydrogen atom - like frequencies of the musical note which is heard when a bell or piano wire is made to vibrate. It now became clear that they had an entirely different origin. The energy exhibited in the spectrum was not liberated by a vibration, or any kind of continuous motion, but by the sudden jump of an electron to an orbit of lower energy, and its frequency was determined by the compulsion put upon it to form a single quantum.”

Source: Lectures on Quantum Mechanics (2012, 2nd ed. 2015), Ch. 1: Historical Introduction

Joseph von Fraunhofer's Gesammelte Schriften (1888) p. 10, as quoted by Florian Cajori, A History of Physics in its Elementary Branches http://books.google.com/books?id=eegKAQAAIAAJ (1917)

Address to the British Association for the Advancement of Science (1898)
Context: The structure of brain and nerves being similar, it is conceivable there may be present masses of such nerve coherers in the brain whose special function it may be to receive impulses brought from without through the connecting sequence of ether waves of appropriate order of magnitude. Röntgen has familiarized us with an order of vibrations of extreme minuteness compared with the smallest waves with which we have hitherto been acquainted, and of dimensions comparable with the distances between the centers of the atoms of which the material universe is built up; and there is no reason to suppose that we have here reached the limit of frequency. It is known that the action of thought is accompanied by certain molecular movements in the brain, and here we have physical vibrations capable, from their extreme minuteness, of acting direct on individual molecules, while their rapidity approaches that of the internal and external movements of the atoms themselves.
Confirmation of telepathic phenomena is afforded by many converging experiments and by many spontaneous occurrences only thus intelligible. The most varied proof, perhaps, is drawn from analysis of the subconscious workings of the mind, when these, whether by accident or design, are brought into conscious survey. … This is not the place for details, but the vis medicatrix thus evoked, as it were, from the depths of the organism, is of good omen for the upward evolution of mankind.

Source: Lectures on Quantum Mechanics (2012, 2nd ed. 2015), Ch. 1: Historical Introduction

Physics and Philosophy (1942)

in Scientific American, September 1959

Physics and Philosophy (1942)

First attibution is to Ralph Bergstresser who claims to have heard this from Tesla in a conversation "following an experience with the Maharaja's son".
Disputed
Source: Coments From The Inventor of the Purple Harmony Plates http://www.bibliotecapleyades.net/ciencia/esp_ciencia_universalenergy02.htm,

[Seismology and plate tectonics, 1990, http://books.google.com/books?id=tZRxPzwoChIC&pg=PA5] (p. 5)
Seismology and Plate Tectonics (1990)