[Sidenote: The plan of the _Janua_.] =His Series of Latin Texts.=--The first of the famous texts that Comenius produced to facilitate the study of Latin was issued in 1631, and has generally been known by the name of _Janua Linguarum Reserata_ (The Gate of Languages Unlocked). It was intended as an introductory book to the study of Latin, and consisted of an arrangement into sentences of several thousand Latin words for the most familiar objects and ideas. The Latin was printed on the right-hand side of the page, and on the left was given a translation in the vernacular. By this means the pupil obtained a grasp of all ordinary scientific knowledge and at the same time a start in his Latin vocabulary. In writing this text, Comenius may have been somewhat influenced by Ratich, a review of whose methods he had read at Herborn, but he seems to have been more specifically indebted both for his method and the felicitous name of his book to a Jesuit known as Bateus, who had written a similar work. [Sidenote: The _Vestibulum_,] [Sidenote: _Atrium_,] [Sidenote: _Palatium_,] [Sidenote: and _Orbis Pictus_.] It was soon apparent that the _Janua_ would be too difficult for beginners, and two years later Comenius issued his _Vestibulum_ (Vestibule), as an introduction to it. While the _Janua_ contained all the ordinary words of the language,--some eight thousand, there were but a few hundred of the most common in the _Vestibulum_. Later both of the works were several times revised, modified, and enlarged; and grammars, lexicons, and treatises were written to accompany them. He also published a third Latin reader, the _Atrium_ (Entrance Hall), which took the pupil one stage beyond the _Janua_. We know, too, that he intended also to write a still more advanced work, to be called _Sapientiae Palatium_ (Palace of Wisdom). This fourth book was to consist of selections from the best Latin authors, but it was never completed. He did, however, produce as a supplementary text-book a simpler and more extensive edition of the _Janua_, accompanied with pictures. Each object in the illustrations of this book was marked with a number corresponding to one in the text. This work, which he called _Orbis Sensualium Pictus_ (The World of Sense Objects Pictured), is the first illustrated reading book on record (Fig. 21). [Sidenote: Indebtedness to others.] [Sidenote: His aim and organization of education.]