Brahmanda and the Pinda. The ancient Norse mythology gave the name "Ginnungagap" to the primordial "Chaos", which was bounded upon the northern side by the cold and foggy "Niflheim"—the land of mist and fog—and upon the south side by the fire "Muspelheim". When heat and cold entered into space which was occupied by Chaos or Ginnungagap, they caused the crystallization of the visible universe. In the medieval West and Middle East, one finds reference to four worlds (olam) in Kabbalah, or five in Sufism (where they are also called tanazzulat; "descents"), and also in Lurianic Kabbalah. In Kabbalah, each of the four or five worlds are themselves divided into ten sefirot, or else divided in other ways. Esoteric conceptions The alchemists of the Middle Ages proposed ideas about the constitution of the universe through a hermetic language full of esoteric words, phrases, and signs designed to cloak their meaning from those not initiated into the ways of alchemy. In his "Physica" (1633), the Rosicrucian alchemist Jan Baptist van Helmont, wrote: "Ad huc spiritum incognitum Gas voco" q.e., "This hitherto unknown Spirit I call Gas." Further on in the same work he says, "This vapor which I have called Gas is not far removed from the Chaos the ancients spoke of." Later on, similar ideas would evolve around the idea of 'aether'. In the late 19th century, the metaphysical term "planes" was popularised by the theosophy of H. P. Blavatsky, who in The Secret Doctrine and other writings propounded a complex cosmology consisting of seven planes and subplanes, based on a synthesis of Eastern and Western ideas. From theosophy the term made its way to later esoteric systems such as that of Alice Bailey, who was very influential in shaping the worldview of the New Age movement. The term is also found in some Eastern teachings that have some Western influence, such as the cosmology of Sri Aurobindo and some of the later Sant Mat, and also in some descriptions of Buddhist cosmology. The teachings of Surat Shabd Yoga also include several planes of the creation within both the macrocosm and microcosm, including the Bramanda egg contained within the Sach Khand egg. Max Theon used the word "States" (French Etat) rather than "Planes", in his cosmic philosophy, but the meaning is the same. The planes in Theosophy were further systematized in the writings of C.W. Leadbeater and Annie Besant. In the