In the works of Joseph Smith, which teach that there is no real line of demarkation between the natural and spiritual worlds, it would be not surprising to find recognized the scientific principle, above discussed, that by the use of proper instruments, the world outside of the five senses, may be brought within man's consciousness. According to the story of Joseph Smith, he was first visited by an angel, September 21, 1823, when the Prophet was less than eighteen years of age. Among other things, the angel told the boy that "there was a book deposited, written on gold plates," giving an account of the former inhabitants of the American continent; "also, that there were two stones in silver bows--and these stones, fastened to a breastplate, constituted what is called the Urim and Thummim--deposited with the plates; and the possession and use of these stones were what constituted 'Seers' in ancient or former times; and that God had prepared them for the purpose of translating the book."[A] This reference to the Urim and Thummim, and their purpose, makes it clear that the Prophet, at the beginning of his career, recognized (whether consciously or unconsciously we know not), the existence of means or media by which things unknown, such as a strange language, may be converted into forms that can reach the understanding. [Footnote A: History of the Church, vol. 1, p. 12.] [Sidenote: The Book of Mormon was translated by such aids--the Urim and Thummim.] When the actual work of translation began, the Urim and Thummim were found indispensable, and in various places the statement is made that the translation was made, "by means of the Urim and Thummim."[A] On one occasion, when the Prophet, through the defection of Martin Harris, lost a portion of the manuscript translation the Urim and Thummim were taken from him, and the power of translation ceased. Upon the return of the instruments the work was resumed.[B] While it is very probable that the Prophet was required to place himself in the proper spiritual and mental attitude, before he could use the Urim and Thummim successfully, yet it must also be true that the stones were essential to the work of translation. [Footnote A: Doctrine and Covenants, 10:1.] [Footnote B: History of the Church, vol. 1, p. 23.] [Sidenote: Revelations were received by such aids.] The Urim and Thummim were not used alone for translation, but most of the early revelations were obtained by their means. Speaking of those days, the Prophet usually says: "I enquired of the Lord through the Urim and Thummim, and obtained the following."[A] The "stones in silver bows" seemed, therefore, to have possessed the general power of converting manifestations of the spiritual world into terms suitable to the understanding of Joseph Smith. [Footnote A: History of the Church, vol. 1, pp. 33, 36, 45, 49 and 53.]