Aphoristica. In Dee's system of Enochian magic, there were three main techniques: invocation (prayer), scrying (crystal-gazing), and traveling in the body of light. Isaac Newton Isaac Newton (1642–1726/27), despite his renown for his scientific pursuits, held an alchemist's perspective. In the early 18th century, he speculated that material bodies might be transformed into light, connecting this idea with the 'subtle body' of alchemy. Franz Anton Mesmer Franz Anton Mesmer (1734–1815) borrowed from Newton's more occult theories with the intention of finding medical applications. He also built on the work of Richard Mead (1673–1754), who hypothesized that due to the astral nature of the human body, it is subject to an "all‐pervading gravitation emanating from the stars." Mesmer expanded this concept, hypothesizing that bodies were subject to a form of magnetism emanating from all other bodies, not just the stars, which he called 'animal magnetism,' describing it as a "fluid which is universally widespread and pervasive in a manner which allows for no void, subtly permits no comparison, and is of a nature which is susceptible to receive, propagate, and communicate all impressions of movement." Mesmer's theories influenced the Spiritualist traditions. Helena Blavatsky Helena Blavatsky (1831–1891) wrote of the Augoeides, though her own theories of the 'astral body' were derived from the 'subtle body' traditions of Eastern mysticism. Ceremonial magic Éliphas Lévi In the mid-nineteenth century the French occultist Éliphas Lévi (1810–1875) introduced the term 'astral light' in his Dogme et rituel de la haute magie (1856), and wrote of it as a factor he considered of key importance to magic, alongside the power of will and the doctrine of correspondences. Lévi developed a full theory of the 'sidereal body' which for the most part agrees with the Neoplatonic tradition of Proclus, Iamblichus, Plotinus, and Porphyry, though he credited Paracelsus as his source. He considered the astral light to be the medium of all light, energy, and movement, describing it in terms that recall both Mesmer and the luminiferous aether. Lévi's idea of the astral was to have much influence in the English-speaking world due to being adopted by the Hermetic Order of the Golden Dawn and by Aleister Crowley, who believed himself to be Lévi's reincarnation and promoted a number of ideas from his works, including his idea of the true self or True Will, much of his system of ceremonial magic, and his theories of the astral plane and