Fluvii Transitus (Lat.). Or crossing of the River (Chebar). Cornelius Agrippa gives this alphabet. In the Ars Quatuor Coronatorum, Vol. III., part 2, 1890, which work is the Report of the proceedings of the Quatuor Coronati Lodge of Freemasons, No. 2076, will be found copies of this alphabet, and also the curious old letters called Melachim, and the Celestial alphabet, supplied by W. Wynn Westcott, P.M. This Lodge seems to be the only one in England which really does study “the hidden mysteries of Nature and Science” in earnest.
Source: H.P.Blavatsky - The Theosophical Glossary