The Charwoman's Shadow by Lord Dunsany

Next morning Ramon Alonzo rose full early, all impatience to do Mirandola's errand, all eagerness to exercise his new skill. That day the magician was to teach him more spells and alternative ingredients, doubtless with quips at the expense of Matter, scoffs at the vanity of the ambitions of Man, quotations from ancient philosophers, and lore of his own seeking. An opportunity not given to every young man; for this master had gathered and stored with his own hands the fruits of many ages, besides the lore he was heir to from former philosophers.

When Ramon Alonzo entered the room that was sacred to magic he saw with a sudden joy that this opportunity was not yet to be his. For he had come down the spiral stair of timber and stone by the palest earliest light, and the magician was not yet about. But with his new learning glowing bright and fresh in his mind he ran a sure eye over the Master's shelves and saw the ingredients he needed. Then he took from a jar some dust of Ozymandias and mixed it in right proportions with some of the dust of Helen. His shrewd young mind guessed well the aphorisms that the Master would have uttered over these pinches of dust; for, secure with his doses of elixir vitae, he neglected few chances to mock the illusions of Man. Attar of roses and crocodile's tears were close by in their vials, and the dried skin of a nightingale hung on a nail near. He procured a flame and burned some of the feathers and pounded them into a powder, and mixed it up with the rest. Then he hastened towards the wood, anxious to gain the door before the magician came, and to do the work unaided; for he knew that the aged had often ideas of their own, setting undue store by ritual and unprofitable quotations, and hindering eager work that the young would do in a hurry. He came to the door to the wood and listened a moment acutely. Not a sound came from the corridors; the magician was not yet afoot. The dew was yet in the wood, and of this he got a small cupful, gathering it drop by drop from the bent blades of grass; and here he found large snails and, after a while, a glowworm. And these he carried into a hollow oak where the darkness was deep enough to be lit by the glowworm; and in the light of that he put all his mixture together, saying the while a spell that had great repute in Persia. The viscid substance he poured into a vial, out of the common mortar in which he compounded it, and carefully corked the vial and turned back towards the house in the wood. And, attracted by the croon of the curious Persian spell, or else by the scent of the love-potion, small things of the wood were lured to follow him. He heard the pattering of their feet behind him; but if he turned they were away on the other side of the oak-boles, and if he went back to a tree behind which one hid and walked round to the other side, he heard small fingernails scratching, always on the far side from him, and knew the small creature had gone up the tree and slipped round it whenever he moved, so as to keep the trunk between it and anything human. They were only imps, light creatures composed of the idleness and mystery of the wood, and led now by curiosity, which was their principal motive. Soon the pattering of footsteps ceased, for they dared come no nearer to the magician's house, but sat down behind their trees uttering little cries of wonder.