The great German alchemist of the early sixteenth century, best known under his assumed name, Paracelsus, collected a vast amount of information and made many important contributions to medical and chemical knowledge.
The science of the times, however, compelled him to sail some uncharted seas, and we might today laugh at some of his theories.
Thus the title of one of his writings is Liber de Nymphis, Sylphis, Pygmeis, et Salamandris et Ceteris Spiritibus (Book concerning Nymphs, Sylphs, Pygmies, and Salamanders and Other Spirits). His intent was to account for and describe the four elements of the alchemists, water, air, earth, and fire.
The nymphs, in his system, were the spirits of water (later disciples called them Undines); sylphs were spirits of the air; pygmies (later called gnomes) were spirits of the earth, and salamanders were spirits of fire.
The term sylph was coined by Paracelsus. He regarded these elemental spirits of the air as being in all respects like man, though able to move with greater agility and speed, and having bodies more diaphanous than man.
Probably through the influence of Pope’s Rape of the Lock, in which the term appeared, the concept of sylph became altered to apply only to a girl or woman of graceful form and movement.