It struck the mind of Champollion, that, if the Egyptian hieroglyphics were _ideographic_, there must be _exceptions_, for two substantial reasons: first, because _proper names_, or names of persons, do not always admit of being expressed by any sign, that is, proper names have not in all cases a meaning; and, second, because _foreign names_, or those which have no relation to any particular spoken language, could not be represented by conventional signs. These principles appear now to be self-evident, and this is the basis of Champollion's discovery. On this he built the idea, that there must exist among the Egyptians _alphabetic characters_, which should express the _sounds_ of the spoken language; and, in order to test this principle, he set about the investigation of the celebrated Rosetta stone. This stone, let it be remembered, had on it _three inscriptions in different characters_. One of these inscriptions was written in Greek, and of course easily decyphered; of the other two, one was written in hieroglyphics, and the other in the common character of the country. The course pursued by Champollion, was exceedingly simple, and, on that account, may be considered masterly. In the Greek text, the name of Ptolemy occurred, together with some names which were foreign to the Egyptian language. In the hieroglyphic inscription, there were certain signs grouped together and frequently repeated; and, what rendered them remarkable was, that they were enclosed in a kind of oval or ring, called a cartouche, and maintained a relative position which seemed to correspond with the Greek word Ptolemy. Champollion conjectured, that there must be some connection between the signs clustered in these rings, and the name of Ptolemy expressed by signs, which would _sound_ like that word; and this led him to expect, that he would get at what he was persuaded was the truth, viz. that the hieroglyphic writing was _alphabetic,_ rather than exclusively _ideographic_. With the view of testing this, he went into a close analysis of the group of signs which he supposed designated the name of Ptolemy; and, as the result of this analysis, obtained what he considered the equivalents to the letters in the name of this prince.