It is by the aid of the etheric elemental essence also that the remarkable feat of handling fire unharmed is generally performed, though there are as usual other ways in which it can be done. The thinnest layer of etheric substance can be so manipulated as to be absolutely impervious to heat, and when the hand of a medium or sitter is covered with this he may pick up burning coal or red-hot iron with perfect safety. [Sidenote: Transmutation.] Most of the occurrences of the _seance_-room have now been referred to, but there are one or two of the rarer phenomena of the outer world which must not be left quite without mention in our list. The transmutation of metals is commonly supposed to be a mere dream of the mediaeval alchemists, and no doubt in most cases the description of the phenomenon was merely a symbol of the purification of the soul; yet there seems to be some evidence that it was really accomplished by them on several occasions, and there are petty magicians in the East who profess to do it under test conditions even now. Be that as it may, it is evident that since the ultimate atom is one and the same in all substances, and it is only the methods of its combination that differ, any one who possessed the power of reducing a piece of metal to the atomic condition and of re-arranging its atoms in some other form would have no difficulty in effecting transmutation to any extent that he wished. [Sidenote: Repercussion.] The principle of sympathetic vibration mentioned above also provides the explanation of that strange and little-known phenomenon called repercussion, by means of which any injury done to, or any mark made upon, the astral body in the course of its wanderings will be reproduced in the physical body. We find traces of this in some of the evidence given at trials for witchcraft in the middle ages, in which it is not infrequently stated that some wound given to the witch when in the form of a dog or a wolf was found to have appeared in the corresponding part of her human body. The same strange law has sometimes led to an entirely unjust accusation of fraud against a medium, because, for example, some colouring matter rubbed upon the hand of a materialized "spirit" was afterwards found upon his hand--the explanation being that in that case, as so often happens, the "spirit" was simply the medium's astral body or perhaps even his etheric double, forced by the guiding influences to take some form other than his own. In fact the astral and physical bodies are so intimately connected that it is impossible to touch the keynote of one without immediately setting up exactly corresponding vibrations in the other. CONCLUSION.