The above question is frequently asked the student of occultism by someone who has heard the term but who is unfamiliar with its meaning. Simple as the question may seem, it is by no means easy to answer it plainly and clearly in a few words unless the hearer already has a general acquaintance with the subject of occult science. Let us commence at the beginning and consider the question from the point of view of the person who has just heard the term for the first time.
The dictionaries define the word aura as: “Any subtle, invisible emanation or exhalation.” The English authorities, as a rule, attribute the origin of the word to a Latin term meaning “air,” but the Hindu authorities insist that it had its origin in the Sanskrit root at, meaning the spoke of a wheel, the significance being perceived when we remember the fact that the human aura radiates from the body of the individual in a manner similar to the radiation of the spokes of a wheel from the hub thereof. The Sanskrit origin of the term is the one preferred by occultists, although it will be seen that the idea of an aerial emanation, indicated by the Latin root, is not foreign to the real significance of the term.
Be the real origin of the term what it may, the idea of the human aura is one upon which all occultists are in full agreement and harmony, and the mention of which is found in all works upon the general subject of occultism. So we shall begin by a consideration of the main conception thereof, as held by all advanced occultists, ancient and modern, omitting little points of theoretical variance between the different schools.
Briefly, then, the human aura may be described as a fine, ethereal radiation or emanation surrounding each and every living human being. It extends from two to three feet, in all directions, from the body. It assumes an oval shape--a great egg-shaped nebula surrounding the body on all sides for a distance of two or three feet. This aura is sometimes referred to, in ordinary terms, as the “psychic atmosphere” of a person, or as his “magnetic atmosphere.”
This atmosphere or aura is apparent to a large percentage of persons in the sense of the psychic awareness generally called “feeling,” though the term is not a clear one. The majority of persons are more or less aware of that subtle something about the personality of others which can be sensed or felt in a clear though unusual way when the other persons are near by, even though they may be out of the range of the vision. Being outside of the ordinary range of the five senses, we are apt to feel that there is something queer or uncanny about these feelings of projected personality. But every person, deep in his heart, knows them to be realities and admits their effect upon his impressions regarding the persons from whom they emanate. Even small children, infants even, perceive this influence and respond to it in the matter of likes and dislikes.
But human testimony regarding the existence and character of the human aura does not stop with the reports of the psychic senses to which we have just referred. There are many individuals of the race--a far greater percentage than is generally imagined--who have the gift of psychic sight more or less developed. Many persons have quite a well-developed power of this kind, who do not mention it to their acquaintances for fear of ridicule, or of being thought “queer.” In addition to these persons, there are here and there to be found well-developed, clear-sighted or truly clairvoyant persons whose powers of psychic perception are as highly developed as are the ordinary senses of the average individual. And the reports of these persons, far apart in time and space though they may be, have always agreed on the main points of psychic phenomena, particularly in regards to the human aura.
To the highly developed clairvoyant vision, every human being is seen as surrounded by the egg-shaped aura of two or three feet in depth, more dense and thick in the portion nearest the body, and then gradually becoming more tenuous, thin and indistinct as the distance from the body is increased. By the psychic perception, the aura is seen as a luminous cloud--a phosphorescent flame--deep and dense around the center and then gradually shading into indistinctness toward the edges. As a matter of fact, as all developed occultists know, the aura really extends very much farther than even the best clairvoyant vision can perceive it, and its psychic influence is perceptible at quite a distance in many cases. In this respect it is like any flame on the physical plane--it gradually fades into indistinctness, its rays persisting far beyond the reach of the vision, as may be proved by means of chemical apparatus, etc.
To the highly developed clairvoyant vision, the human aura is seen to be composed of all the colors of the spectrum, the combinations of colors differing in various persons, and constantly shifting in the case of every person. These colors reflect the mental (particularly the emotional) states of the person in whose aura they are manifested. Each mental state has its own particular combination formed from the few elementary colors which represent the elementary mental conditions. As the mind is ever shifting and changing its states, it follows that there will ever be a corresponding series of shifting changes in the colors of the human aura.
The shades and colors of the aura present an ever changing kaleidoscopic spectacle of wonderful beauty and most interesting character. The trained occultist is able to read the character of any person, as well as the nature of his passing thoughts and feelings, by simply studying the shifting colors of his aura. To the developed occultist, the mind and character become as an open book, to be studied carefully and intelligently.
Even the student of occultism who has not been able to develop the clairvoyant vision to such a high degree is soon able to develop the sense of psychic perception whereby he is able to at least “feel” the vibrations of the aura, though he may not see the colors, and thus be able to interpret the mental states which have caused them. The principle is, of course, the same, as the colors are but the outward appearance of the vibrations themselves, just as the ordinary colors on the physical plane are merely the outward manifestation of vibration of matter.
But it must not be supposed that the human aura is always perceived in the appearance of a luminous cloud of ever-changing color. When we say that such is its characteristic appearance, we mean it in the same sense that we describe the ocean as a calm, deep body of greenish waters. We know, however, that at times the ocean presents no such appearance, but instead is seen as rising in great mountainous waves, white capped and threatening the tiny vessels of men with its power. Or again we may define the word flame in the sense of a steady bright stream of burning gas, whereas we know only too well that the word also indicates the great hot tongues of fiery force that stream out from the windows of a burning building and lick to destruction all with which it comes in contact.
So it is with the human aura. At times it may be seen as a beautiful, calm, luminous atmosphere, presenting the appearance of a great opal under the rays of the sun. Again, it blazes like the flames of a great furnace, shooting forth great tongues of fire in this direction and that, rising and falling in great waves of emotional excitement or passion, or perhaps whirling like a great fiery maelstrom toward its center, or swirling in an outward movement away from its center. Again, it may be seen as projecting from its depths smaller bodies or centers of mental vibration, which like sparks from a furnace detach themselves from the parent flame and travel far away in other directions--these are the projected thought forms of which all occultists are fond of speaking and which make plain many strange psychic occurrences.
So, it will be seen, the human aura is a very important and interesting phase of the personality of every individual. The psychic phase of man is as much the man himself as is the physical phase--the complete man being made up of the two phases. Man invisible is as much the real man as is man visible. As the finer forms of nature are always the most powerful, so is the psychic man more potent than the physical man.
In this book, I speak of the human aura and its colors as being perceived by astral or clairvoyant vision, for this is the way in which it is perceived and studied by the occultist. The occult teaching is that, in the evolution of the race, this astral vision will eventually become the common property of every human being--it so exists even now, and needs only development to perfect it.
But modern physical science is today  offering corroborative proof (though the same is not needed by the occultist who has the astral vision) to the general public, of the existence of the human aura. In Europe especially, a number of scientists have written on the subject of the aura, and have described the result of the experiments in which the aura has been perceived, and even photographed, by means of fluorescent screens, such as are used in taking X-ray photographs, etc. Leading authorities in England, France, and still more recently, in Germany, have reported the discovery (!) of a nebulous, hazy, radioactive energy or substance around the body of human beings. In short, they now claim that every human being is radioactive, and that the auric radiation may be registered and perceived by means of a screen composed of certain fluorescent material interposed between the eye of the observer and the person observed.
This aura, so discovered (!) by the scientists, is called by them the “human atmosphere” and is classified by them as similar to the radiations of other radioactive substances, radium, for instance. They have failed to discover color in this atmosphere, however, and know nothing, apparently, of the relation between auric colors and mental and emotional states, which are so familiar to every advanced occultist. I mention this fact merely as a matter of general interest and information to the student, and not as indicating, even in the slightest degree, any idea on my part that the old occult teaching and the observed phenomena accompanying the same regarding the human aura require any proof or backing up on the part of material scientists. On the contrary, I feel that material science should feel flattered by the backing up by occult science of the new discovery (!) of the “human atmosphere.” A little later on, material science may also discover (!) the auric colors and announce the same to the wondering world as a new truth.