SENSITIVES you now know, and the element which they move you know, namely, that force of nature which I have designated by the word "Od." But with all that we have only lifted one corner of the hem of the great odic garment in which the universe has wrapped itself. That remarkable for of od streams not only from the poles of the crystal but gushes also from numerous other sources in the great world of being just as strongly, and even more strongly still.

First and foremost I shall take you to the star: and, in fact, to the sun itself. Post a sensitive person in the shade, give him an ordinary unfilled barometer tube, or any other sort of glass rod, or even a wooden stick, in his left hand, and let him hold the rod i the sunshine, while his person and hand remain in the shade. You will shortly learn something from this simple experiment that will surprise you. You naturally expect that the person experimenting will perhaps feel the rod getting warm; the most that can happen will surely be that the sunshine will warm it up.

But you will hear exactly the opposite: the sensitive's hand will feel a number of effects, but the sum-total of them all will be—a coolness. If such a hand withdraw the rod into the shade, the coolness will vanish, and the hand will feel the rod getting warm; if it put the rod back into the sunshine the rod will once more grow cool to its sensor perception; it can check the correctness of its own sensations by continuing to change about from one position to the other.

There are consequently some very simple, but so far unobserved, factors in existence under the influence of which the direct sunbeam not only does not warm, but, in a most unexpected and unusual manner, cools. And as to this coolness, sensitives will tell you that it bears every resemblance in its effects to those exercised by the coolness felt from the upper peak of the mountain-crystal.

Now, if this coolness is something in the nature of od, it will necessarily frnd some expression in the dark as a phenomenon of light. You will succeed in finding this out if you will perform one of my experiments as follows: I hung a copper wire so as to go from a fully lighted room into the darkness of the camera obscura. Then I put the end of the wire out into the sunshine. Scarcely was this done when the part of the wire that was in the dark began to get luminous, and a small, flame-like phenomenon, the size of a finger, rose up at its extremity. The sunshine consequently infused an odic element into the wire, seen by sensitives streaming out in the darkness under the form of light.

But take one step further; let the sunbeam fall on a good glass prism, and throw the colours of the rainbow on to the nearest wall. Let the sensitive person with the glass rod in his left hand try the colours one after the other. If he hold it so as to catch only the blue or violet colour in the air, the sensation that this will excite in him will be one of a highly agreeable coolness, much purer and cooler than that which occurred with the unrefracted sunbeam. If, instead of this, he puts the rod into the yellow ray, or, better still, into the red ray, the comfortable feeling of coolness will vanish on the instant, and be replaced by one of heat; a disagreeable lukewarmness will make his whole arm heavy.

You can make the sensitive hold a bare finger on the colours, instead of using the rod as intermediary; the effect will be the same; I only devised the rod for the purpose of shutting off the actual heat rays from his hand by means of a bad conductor of heat. These effects of refracted sunlight will be found exactly similar to those of the poles of the crystal. Hence you see: od exercising both kinds of effect is contained in the sunbeam; it streams towards us from our star of day every moment in immeasurable floods, along with the light and heat, and forms a newly discovered mighty solar agent, the extent of whose functions we have no present means of estimating.

Will you now let me ask you to look back for a moment to the foe to yellow and friend to blue I spoke of in my first letter? Have we not seen that the pole of the crystal that breathed forth an agreeable coolness was one that emitted blue light? And do we not here, by quite a different route, come upon sunlight distributing with its blue ray an extremely agreeable and refreshing coolness? And, vice versa, had not the red-yellow light of the other pole of the crystal, and also the red-yellow ray of the sun, produced feelings of nausea and discomfort in the sensitives?  You see how in two cases, standing so infinitely wide apart, blue had invariably for its sequel sensations of comfort, and red-yellow feelings of discomfort. Herewith you receive a preliminary hint to put you on your guard against all rash judgment of sensitive persons in the matter of their alleged whims. You see that, in fact, something more must lie hidden in the yellow and blue of our colours than their mere optical effect on the retina of the eye, that here a deep-down, instinctive sense of a subtle, unknown something guides the feeling and intuitive judgment of our sensitives, and that this is a matter worth the utmost efforts of our powers of observation.

Now, leaving colours on one side, I wish to arm you with one more easy experiment that I have often made for isolating the odic content of sunbeams. Polarize them in the ordinary way, so that they fall at an angle of 35° on a bundle of a dozen panes of glass. Then let the sensitive observer hold the rod in his left hand now in the reflected light and now in the light that has passed through. You will always hear that the former sends odic cool and the latter odic mawkishness along the rod to the sense of feeling in the hand.

If you are in the mood, you can take a little rise out of the chemists in this connection. Get two similar glasses of water and put one standing in the reflected and the other in the filtered sunlight. After they have been there six to eight minutes, let a sensitive sip from them. He will tell you at once that the water taken out of the reflected light tastes cool and slightly acidulous, and that the water taken out of the filtered light tastes mawkish and somewhat bitter. Do something more: put a small glass vessel filled with water in the blue light of the spectrum, and another one in the orange; or put one of them at the pointed end of a large mountain-crystal, and the other at the butt-end. In all these cases you may be sure that the sensitive will find the water that has been in the blue light pleasant, and lightly acidulated, and that which has been in the orange nauseating, rather bitter, and crude. He will drink the first glass off with pleasure, if you let him do so; but, if you force him into drinking the other, an event may betide you that happened once to myself, namely, that the sensitive shortly afterwards had a violent fit of vomiting. Now give the water to the gentlemen of the analytical profession, and ask them to try out the elements of the "amarum" and the "acidum" from it.

Proceed with the moonlight as you have done with the sunlight. You will obtain similar, but in part polarically contrasted results. A glass rod held by a sensitive's left hand in full, pure moonlight will not yield him coolness, but lukewarmness. A glass of water that has been some time in the moonlight he will find tasting more insipid and mawkish than another that has been standing a moderate time in the shade. Everyone knows the great influence the moon has on many people; all persons subject to its influence are without exception sensitives, and as a rule pretty keenly sensitive. And, as the moon demonstrably exercises odic effects, while its influence on lunatic patients corresponds exactly with the effects that can be produced through other odic sources, it is as an od-distributive star of great importance for us.

The element of odic force is thus radiated towards us so abundantly by sunlight and moonlight that we can lay hold of it at our ease and make use of it in simple experiments. How unbounded its influence is on the whole of humanity, and even on the whole animal and vegetable kingdom, will be proved shortly. Od is, accordingly, a cosmic force that radiates from star to star, and has the whole universe for its field, just like light and heat.