It is not merely in material ways that man has progressed with such amazing rapidity, for some of his inventions and discoveries touch the invisible regions. The doors of man’s mind are opening on the untracked spaces of aether in which these beings live. Man is chaining the elements, and to chain the elements _may_ be to chain the elementals. One man in America has come so near to a great and dangerous secret that his eyes have had to be veiled by those who fear for man’s too rapid progress. Occult societies dot the world. In other days these societies were really secret, and no one had access to their knowledge until after tests were passed which proved fitness for further study and further secrets. But the doors of the unseen have been besieged by an army of intellectual enthusiasts who have not passed those tests. Curiosity demands to know that which only the nobility of the spirit was once trusted with. Democracy has spread even into the occult orders, and sacred mysteries have been published broadcast by those who put no curb upon their personal ambitions. The hosts of the unseen world have themselves suffered invasion. Now the hosts of the unseen will obey a great soul that they know to be more powerful than themselves. They run like docile children at his call, and they go at his command as a dog goes. But the unseen hosts are very jealous of their freedom, and they will yield it only to one whose superiority is manifest to them. Many--yes, most--of those who are now seeking to open the doors of that region are unfit to command there; because he only can command the unseen forces outside who can command the unseen forces _inside_ himself. In a former letter I spoke of the danger of black magic in America; but the danger is everywhere. And what is black magic? It may be briefly defined as a use for selfish purposes of those very forces of the unseen world. Not until a man has advanced beyond himself will the invisible forces serve him long without rebellion. Pick up a common newspaper, and you will see the advertisements of men and women who promise _for a fee_ to bring about results which can only be brought about by using those invisibles. What blasphemy! What presumption! If these advertisers could make good their claims, they would be more dangerous than typhus fever. Such advertisements arouse all the curiosity and ambition and fiery selfishness latent in the heart of the ignorant. These untrained dabblers in the mysteries attempt to do things which an Adept would never dream of doing, for most of their efforts have for purpose some attack upon the free will of others; they seek to influence the desires and the judgment of others in the narrow and personal interest of those who pay them to set the forces in operation. Would you let a child loose in a gunpowder factory with a box of matches in his hand? That is what has been done in the last few years all over the western world.