FORMS OF WRITING.--The Egyptians employed three forms of writing: the _hieroglyphical_, consisting of rude pictures of material objects, usually employed in monumental inscriptions; the _hieratic_, an abbreviated or rather simplified form of the hieroglyphical, adapted to writing, and forming the greater part of the papyrus manuscripts; and the _demotic_, or _encorial_, a still simpler form than the hieratic. The last did not come into use till about the seventh century B.C., and was then used for all ordinary documents, both of a civil and commercial nature. It could be written eight or ten times as fast as the hieroglyphical form. KEY TO EGYPTIAN WRITING.--The key to the Egyptian writing was discovered by means of the Rosetta Stone. This valuable relic, a heavy block of black basalt, is now in the British Museum. It holds an inscription, written in hieroglyphic, in demotic, and in Greek characters. Champollion, a French scholar, by comparing the characters composing the words Ptolemy, Alexander, and other names in the parallel inscriptions, discovered the value of several of the symbols; and thus were opened the vast libraries of Egyptian learning. We have now the Ritual, or Book, of the Dead, a sort of guide to the soul in its journey through the underworld; romances, and fairy tales, among which is "Cinderella and the Glass Slipper"; autobiographies, letters, fables, and epics; treatises on medicine, astronomy, and various other scientific subjects; and books on history--in prose and verse--which fully justify the declaration of the Egyptian priests to Solon: "You Greeks are mere children, talkative and vain; you know nothing at all of the past." ASTRONOMY, GEOGRAPHY AND ARITHMETIC.--The cloudless and brilliant skies of Egypt invited the inhabitants of the Nile valley to the study of the heavenly bodies. And another circumstance closely related to their very existence, the inundation of the Nile, following the changing cycles of the stars, could not but have incited them to the watching and predicting of astronomical movements. Their observations led them to discover the length, very nearly, of the sidereal year, which they made to consist of 365 days, every fourth year adding one day, making the number for that year 366. They also divided the year into twelve months of thirty days each, adding five days to complete the year. This was the calendar that Julius Cæsar introduced into the Roman Empire, and which, slightly reformed by Pope Gregory XIII. in 1582, has been the system employed by almost all the civilized world up to the present day.