A Wanderer in the Sprit Lands, by Franchezzo (A. Farnese), [1896], at sacred-texts.com
Hassein laughed. "I could give a dozen elaborate explanations, but neither you nor these mortals who are unable to see the spirits would be much wiser after I had done so. I must, therefore, endeavor to make my answer as free from technicalities as I can. First, though, let me ask if you have seen the photographs of unmaterialized spirits which have been obtained by certain mediums in the flesh. You will have noticed that to mortal sight they present a semi-transparent appearance. The material doors and windows, furniture, etc. show through the figures of the spirits.
"Now that gives you a very good idea of the amount of materiality possessed by an astral body (the first degree of spiritualized matter). The material particles are spread so thinly that they are like a fine net-work united by invisible atoms of a more etherealized nature--so sublimated in fact that they cannot be impressed upon the most sensitive plates now used by photographers. Spirits after they leave the earth plane cannot be photographed by the plates now in use--they do not possess gross enough atoms in the composition of their bodies, and have therefore to either materialize a body like an earthly one, or they may use another method which has been found successful and which is the one commonly used in the case of spirit photographs, where the spirits are visible to clairvoyant sight though invisible to material eyes. This is simply described by saying these spirits make use of some of those astral envelopes or bodies that I have already described to you as forming from cloud masses of semi-material human atoms--astral shells which never served as the covering of any soul, and which are so plastic in their nature that spirits can mold them into their own likeness as a sculptor molds the clay. These replicas can be and are photographed, bearing a greater or less resemblance to the spirit, according as his will power and his knowledge enable him to stamp his likeness upon them, and though they are not strictly speaking the photos of the spirits themselves, yet they are none the less evidence of spirit power and of the existence of the spirit who has made use of them, because each spirit must himself stamp his own identity upon the plastic astral form, while more advanced scientific spirits prepare that form to receive the impression.
"In the case of materialized spirits' photographs, the spirits really make a body from the more material atoms and clothe themselves in it.
"A clairvoyant seeing one of these astral forms about to be photographed would probably not be able to distinguish between it and a true spirit man or woman, because the power of distinguishing between them is not yet developed in mediums, neither, as a rule, do they know why a spirit that looks solid enough to them comes out on a photographic plate with a semi-transparent appearance. The see the more spiritualized matter as well as the grosser astral atoms, therefore it appears to them as a solid body with well-rounded, well proportioned limbs, not as a transparent shadow of a spirit whose appearance may well give rise to the idea that returning spirits are mere shades, almost, in fact, empty shells--the real reason of the empty appearance being that, as I have said, the photographic appliances at present in use are not capable of transferring the whole spirit's form but only these grosser particles. In the case of a fully materialized spirit being photographed, this transparent appearance does not exist. The form is so perfect, so life-like and solid, that men turn round and say it, therefore, cannot be a spirit photograph at all--it must be nothing but the medium. Blind seekers, who in trying to grasp a subject so vast, so full of the most subtle difficulties, bring to bear upon it only the knowledge suitable for mundane things, and then conclude that they are able to decide finally so momentous, so scientific a question!
"But to return to your question. Having shown you how a photograph may give a spirit whose appearance is like that of the traditional ghost, I will now show you how mortals may also see them as such, but to illustrate my meaning I will first ask you to imagine yourself back in your earthly body with no more powers of spirit sight than you possessed then. Let us liken the material and spiritual sight to two eyes. The one we will call the left, the other the right eye, and let the left stand for the material sight, the right the spiritual. Suppose you stand with your back to the light and hold your forefinger in front of the right eye where it can be seen by that eye only, the left seeing only the wall before you--shut the right eye and the finger is invisible, yet it is there, only not in the line of vision for the left, or material, sight. Now open both eyes at once and look at your finger and you will now see it certainly, but owing to a curious optical illusion it will appear transparent, a mere shadow of a finger, the wall being seen through it, and it may be likened to a ghost of a finger although you know it to be a solid reality.
"Thus you can imagine how a person whose material sight is alone open cannot see that which requires spiritual sight to discern, and how, when both the material and spiritual sight are open at the same mement a spirit may be visible but with the same transparent appearance as your finger had just now. Hence has arisen the popular idea of a ghost. A clairvoyant, looking at any spiritual object with the spiritual sight, does so with the material sight closed through the power of the controlling intelligence who directs that person's mediumship. Therefore to him or to her the spiritual object does present the appearance of a solid reality such as a material finger appears when seen by the material sight alone.
"Few men know and still fewer consider that even their material sight is dependent upon the material atoms which fill the earth's atmosphere, and without which atoms there would be no light to see anything by.
At night mortals can see the stars--even those which are not themselves suns--distant as they are, because they are material objects from which the light of the sun is reflected. During the day the stars are still there, but the immense mass of material particles in the earth's atmosphere being illuminated by the reflecting of the sun's rays from them, causes so dense an atmosphere of light that the stars are veiled and no longer visible to material eyes. Ascend, however, above this material atmosphere of illuminated atoms, and, behold, the stars are again visible at mid-day and the surrounding ether of space, being free from such material particles, is quite dark. There is nothing to reflect the sun's rays.
Thus, although the mortal would be nearer to the sun, yet its light is no longer visible to his material eyes, which can only see when there is some material object, however small, to reflect the light of the sun for him. How, then, does man know that the light of the sun is traveling through the ether space to earth? Only by reason and analogy, not by sight, for beyond the earth's atmosphere the sun's light is invisible to him. Men know the light of the moon to be only the light of the sun reflected from the moon's surface. Experience and experiment have proved this, and it is now universally admitted. In like manner each little atom of material matter floating in the earth's atmosphere is an infinitesimal moon to reflect the sun's light for man and brighten earth with the splendor of these reflections. So again those minute particles that are continually being thrown off into the atmosphere by the earth itself, are but the larger and grosser atoms enclosing or rather revolving round, minute spiritual germs that form a spiritual atmosphere around the earth and reflect for clairvoyants the spiritual elements of the light of the sun. This spiritual atmosphere forms what is known as the astral plane, and bears the same proportion of density to astral bodies that the material atmosphere does to mortal bodies, and the light from the spiritual elements of the sun striking upon these spiritual particles is the light of the astral plane by which spirits see; the material atmosphere of earth being visible to the material sight of mortals. Is it not, then, easy to imagine that the spirit spheres may exist around the earth, and between man and the material envelope of the sun without his being able to see them, by reason of the fact that his spiritual sight is closed and he can only see what is material? The spiritual spheres and their inhabitants are certainly more transparent and intangible to mortal sight than his finger appeared just now. Yet they exist and are as solid a reality as his finger, and are only invisible by reason of his imperfect sight, which is limited to material things of comparatively great density."