ergies also do actually condition the intensive or qualitative forces which pertain to consciousness. Together they make up one immutable complete constitution.

We can see this fact; it is difficult to put it into words, since language has been so framed that it is well nigh inadequate to express the perception. But a large amount of physical action occasions in us corresponding intensity in every adapted state of consciousness. Also intensity of feeling, strength of volition, perspicacity of thought, each invariably eventuates in a large measure of adapted physical activity. We decide to strike a heavy blow, and we strike it at least we do if the coöperative organism is in good condition. Or we choose to tap with but the little finger; and that prolonged, extensive instrument, the adapted muscle, is obedient to the will. We know that this will-power is conditioned with mechanical force and that both are constituent elements of our essential being.

But we do not find in consciousness the slightest evidence that a unit of motion, of mechanical force, ever is or ever can be transmuted into a state of

consciousness. Every physical process is complete in itself. Every psychical process is complete in itself. They are simply conditioned together as two dependent phases of one activity. They are never alike; but they work together. We must turn to their modes of coöperation.

CO-OPERATION; PHYSICAL AND PSYCHICAL.

Sound vibrations conditioned by extension.-A musical instrument as conditioned.—Consciousness, how related to physical action.— Its active moods may control physical states.-Passive moods controlled by physical states.-Adaptations.-Sound as related to sensation.-Sunbeams and their action.-Relations of motion to growth, etc.

Motion not sensation.-The mind-atom as coöperative with its organism.—Heredity.—A disturbed organism.— Succession of sentient states. They are not quantitatively exchanged. In what sense they are convertible.-Thought.— Conscience and will.-Physical and psychical activities conditioned to work together.

A

MUSICAL note is produced by a definite

number of vibrations in a second; the more rapid the vibrations the higher is the pitch of the sound. But rapidity of vibration is determined by the weight, the structure, and the form of the vibrating substance. Length, thickness, density, and tension of the strings are all made to assist in regulating the concord of sounds in every stringed instrument.

All sound is vibration of something which produces or which conveys the sound. The process is

vibration throughout, vibration of the sonorous substance, of the atmosphere which is thrown into alternate pulses of motion, of the solid medium which conveys the sound, of the nerves of the ear and brain, and, finally, of the physical extension of the mind which hears the sound. But the sensation of hearing is not vibration. This pulses back as vibration and is spread throughout the organism. The physical motion remains motion forever; but the sensation which is conditioned with each class of vibrations, is yet totally unlike it in kind. They have not one trait or feature in common.

The rate of vibration in all stringed instruments is inversely proportional to the diameter of the string; it is inversely proportional to the length of the string; it is inversely proportional to the square root of the density of the string; and it is directly proportional to the square root of the tension of the string. Size, weight, length, and the amount of stretching to which the string is subjected-properties of extension all of them-by their adaptations are made to condition the number of vibrations as to time.

By a method which is closely analogous to that which constitutes the structure of an atom or a molecule in nature, the manufacturer conditions the musical machine. It may be fittingly likened to a vast molecule put together by art, by exquisite human forecast, based upon observation of laws which operate throughout nature. In natural compounds, the adapted attractions of the atoms bind them into a coöperative system. Such attractions operate in the strings, the wood, the ivory; and by adjusting all these each to each, human prevision produces a machine which can give us a magnificent unity of harmonious effects.

It may be made to produce a thousand melodies. as it is played upon from without; but it can do this only according to the laws of perfect action and reaction. It is action and reaction between atom and atom in the same molecule, whether organic or inorganic; whether it be the mental atom or a simply material one. There is action and reaction between the fingers and the keys; between the keys and the strings between the strings and the sounding board; between the sounding board and the at