Isotopes are different types of atoms (nuclides) of the same chemical element, each having a different number of neutrons. In a corresponding manner, isotopes differ in mass number (or number of nucleons) but never in atomic number. The number of protons (the atomic number) is the same because that is what characterizes a chemical element. For example, carbon-12, carbon-13 and carbon-14 are three isotopes of the element carbon with mass numbers 12, 13 and 14, respectively. The atomic number of carbon is 6, so the neutron numbers in these isotopes of carbon are therefore 12-6 = 6, 13-6 = 7, and 14-6 = 8, respectively.
A nuclide is an atomic nucleus with a specified composition of protons and neutrons. The nuclide concept emphasizes nuclear properties over chemical properties, while the isotope concept emphasizes chemical over nuclear. The neutron number has drastic effects on nuclear properties, but negligible effects on chemical properties. Since isotope is the older term, it is better known, and is still sometimes used in contexts where nuclide might be more appropriate, such as nuclear technology. Wikipedia
Keely
This dynaspheric force, which is also called etheric, is conditioned as to its nature on the quality of the atoms which form its transmitting media; and which are infinite both in variety and in their combinations. They may, however, be broadly divided into two categories; viz., the sentient and the non-sentient atoms. Dynaspheric force, composed of non-sentient atoms, is the force that has been already mechanically applied by Mr. Keely to his motor; and which will probably, ere long, supersede the agencies now used for locomotive, projectile, and other purposes. When the laws which govern it come to be understood it will produce materially a great commercial and industrial revolution. There is no hard-and-fast line between the sentient and the non-sentient atoms; just as zoophytes are a connecting link between the animal and vegetable creation, so there is a graduated scale of atoms, between atoms [See isotope] which although animated by the divine life are not sentient, and those which are as highly developed, relatively to them, as man is to a cabbage. [Dynaspheric Force]
Russell
"Radioactivity has so nearly reached its maximum at this point that the speed of the cosmic seed shed by these isotopes has been measured at 180,000 miles per second, which is approximately the speed of light nearing its ending point at tomion where the octave again begins at alphanon." [The Secret of Light, page 145]
"...when science discards its concept of matter as being substance, and becomes aware of the gyroscopic control of motion they will be able to split the carbon tone into isotopes as a musical tone is split into sharps and flats." [Walter Russell]
See Also
atom
Figure 14.01 - Overtones Developed Musically Showing Up as Isotopes along the Vertical Axis of this Chart