Non-observable, intangible, immaterial as opposed to observable, visible and material.
Keely
"The physical organism (through the medium of celestial radiation) is a trinity, both in regard to its visible form and the invisible sympathetic streams which govern it, in its individual and combined movements. The visible includes the molecular, the atomic and interatomic in combination; while the invisible, or spiritual, includes the etheric, interetheric and luminous in combination, each of which is essential to the proper completion of the combined action, comprising as it does every minute law governing the celestial and terrestrial universe." [Newton of the Mind]
""It is through the action of nature's sympathetic forces that planets are born and their volume of matter augmented. If the sympathetic negative polar stream were cut off from the earth, its molecular mass would become independent, and would float away into space as would a soap bubble filled with warm air. The same conditions of governing rule exist in the planetary masses as between the mental and physical forces in our organisms; the organism representing the earth, and its link with the cerebral centers the connection with the infinite mind. In other words, the latent energy existing in the neutral depths of matter, visible or invisible, remains eternally subservient and unchangeably linked to the eternal mind. True science is bastardized by intimating that the life in matter can be destroyed by any intensity of thermal negation (frigidity). Can finite man make use of an infinite element to neutralize infinity? Thermal negation causes molecular oscillation to diminish, or even seem to cease, but the results brought about from this superficial appearance of matter coming to rest are that the latent energy existing in the molecular zone is transferred to the intermolecular, increasing the oscillations of the intermolecular in the same ratio that the molecular is diminished. All the art that man can employ to induce the same effect on the intermolecular zone ends here. Granting, however, that it were possible, what would ensue?" [Newton of the Mind]
"Energy is a sympathetic condition inherent in all forms of aggregated matter, visible and invisible. It is ever present, in its latent condition, and is aroused by the sympathetic disturbers of its equilibrium. By this conservation it becomes transferable. The sympathetic correlation of will force in the cerebral convolutionary centres transfers its energy to the physical organism." [Vibratory Physics - The Connecting Link between Mind and Matter]
Keely stood, fourteen years ago, on the wrong side of the abyss which separates conjecture from fact. "The bridge of mist" he writes, "which spanned the chasm between the two is gradually resolving itself into one of granite, which the nations of the earth may safely traverse, stretching between the two centers; the celestial and terrestrial. The visible one is the one of mist: the invisible one is the one of granite." [from Keely and His Discoveries]
Schauberger
In an already higher form as invisible suspensions, these same substances are contained in the carrier of life-substances - water - and can be made free and active with the use of Repulsators. In their relatively highest evolved form these bacteriophagous threshold stocks are to be found in the air. These indifferent elements of intermediate substances can be liberated by means of cycloid-space-curve-motion in so-called Repulsines, resulting in the intimate fusing of the former carrier-substances, which exit from the lower end of the apparatus, and immediately interact with the surrounding difference-matter, namely substances of a highly polarised nature. This leads to the formation of new juvenile air, which strives to displace itself upwards, because this increased, qualitatively-improved, evolutionally-older air cannot mix with the surrounding older air-masses, which have a different potential. [The Energy Evolution - Harnessing Free Energy from Nature, The Economy Founded on Reactively Produced Energy]
This diagram shows pictorially the open in the spiral of the mathematical scales, in which, if written in sharps only, B# is seen a little, that is, a comma and the apotome minor, in advance of C, and as the first scale of the new cycle; for it is a violation of Nature's beautiful steps to call it a thirteenth scale of this order, since every scale in the order is 31 commas in advance of the preceding, whereas B# is only one comma and a small fraction in advance of C. If the scales be written in ?s and #s for convenience of signature, then G# is seen a comma and apotome in advance of A?; while the whole circle of keys advancing by fifths are each 31 commas in advance of the preceding. We may therefore cast utterly from us the idea of there being more than twelve mathematical scales, and view the so-called thirteenth as simply the first of a new round of the endless spiral of scales. There is, however, in this note a banner with the strange device, "Excelsior," for it leads us onward into ever-advancing regions of vibrations, and would at last bring us to the ultimate and invisible dynamic structure of the visible world. The tempered system of 12 keys, as in Fig. 1, is by causing the G# and A? to coalesce and be one, as the two D's are already literally one by Nature's own doing. [Scientific Basis and Build of Music, page 118]
See Also