=Pedagogical Work.=--The great educational works of Comenius are his "Gate of Tongues Unlocked," the "Great Didactic," and his "Orbis Pictus." Mr. Quick thinks that the "Great Didactic" contains, in the best form, the principles he afterward endeavored to work out"[100] in his other educational writings. "The services of Comenius to pedagogy," says Professor Williams, "were of a threefold character, in each of which his merit was very great. First, he was the true originator of the principles and methods of the Innovators. Second, he was a great educational systematist. Third, he was the author of improved text-books, which were long and widely famous."[101] This is a fair summing up of the remarkable activity of this man with the exception of the first point. Montaigne, Ratke, and Bacon had previously taught many of the fundamental truths which Comenius merely amplified and brought to practical fruition, and he himself acknowledged the influence of the last two men upon him. That the whole purpose of the life of Comenius was far nobler than that of Ratke or Bacon, there remains no room for doubt. Compayre says, "The character of Comenius equals his intelligence. Through a thousand obstacles he devoted his long life to the work of popular instruction. With a generous ardor he consecrated himself to infancy. He wrote twenty works and taught in twenty cities. Moreover, he was the first to form a definite conception of what the elementary studies should be."[102] Bacon gave the inspiration and Comenius worked the truth into practical form; Bacon invented a new theory of scientific investigation, Comenius employed that theory in education; Bacon originated and Comenius applied. This does not detract from the merit of Comenius any more than his work detracts from the merit of Rousseau, Pestalozzi, or Horace Mann, all of whom gathered inspiration from him. =Summary of the Work of Comenius.=--(1) He was the author of the first illustrated text-book, the "Orbis Pictus."[103] The cost of illustrations was for a long time a serious barrier to their general adoption in schoolbooks; but modern inventions and improvements have removed this obstacle, and many of the text-books of to-day are as valuable for their illustrations as for their text. The "Orbis Pictus" appeared in 1658. (2) In his "Great Didactic," he presents a scheme for general organization of the school system which covers the first twenty-four years of life. It divides this time into four equal periods of six years, each as follows:-- 1. _Infancy_, or the mother school, from birth up to six years of age. 2. _Boyhood_, the vernacular or national school, from six to twelve. 3. _Adolescence_, the _Gymnasium_ or Latin school, from twelve to eighteen. 4. _Youth_, the university (including travel), from eighteen to twenty-four.