The Australian blog Oz.Typewriter for June 10 carries a long description of the Yost typewriter invented by George Washington Newton Yost, an American Spiritualist who used his machine to take down the autobiography of the late H.P. Blavatsky. It was published in Boston in 1896 as Posthumous Memoirs of Helena Petrovna Blavatsky. Dictated from the spirit-world, upon the typewriter, independent of all human contact, under the supervision of G. W. N. Yost, to bring to light the things of truth, and affirm the continuity of life and the eternal activity of the soul immortal.
This obscure book belongs to that remote area of Blavatskiana—Posthumous memoirs dictated from the spirit-world—of which it must hold the sole place. The entry for it in Theosophy in the Nineteenth Century: An Annotated Bibliography (1994) gives a brief overview of its contents. It should come as no surprise that the book, which purports to give Blavatsky’s life history as told by herself, upholds the reality of spirit communication. Robert Messenger, who writes the piece, notes that “Yost had died in New York on September 26, 1895, aged 64, and appears not to have made any further contact with the world from the hereafter thereafter.” The post includes a picture of a Yost typewriter.