An examination of these mutual relations and courtesies between studies may discover to us the fact that we are now unconsciously or thoughtlessly _duplicating_ the work of education to a surprising extent. For example, by isolating language lessons and cutting them off from communication with history, geography, and natural science, we make a double or triple series of lessons necessary where a single series would answer the purpose. Moreover, by excluding an interesting subject-matter derived from other studies, the interest and mental life awakened by language lessons are reduced to a minimum. Interest is not only awakened by well selected matter taken from other branches but the relationships themselves between studies, whether of cause and effect as between history and geography, or of resemblance as between the classifications in botany and grammar--the relations themselves are matters of unusual interest to children.
Many teachers have begun to realize in some degree the value of these relations, their effect in enlivening studies, and the better articulation of all kinds of knowledge in the mind. But as yet all attempts among us to properly relate studies are but weak and ineffective approaches toward the solution of the great problem of concentration. The links that now bind studies together in our work are largely accidental and no great stress has been laid upon their value, but if concentration is grappled with in earnest it involves _relations at every step_. Not only are the principal and tributary branches of knowledge brought into proper conjunction, but there is constant forethought and afterthought to bring each new topic into the company of its kindred, near and remote. The mastery of any topic or subject is not clear and satisfactory till the grappling hooks that bind it to the other kinds of knowledge are securely fastened.
Concentration on a large scale and with consistent thoroughness has been attempted in recent years by the scholars and teachers of the _Herbart school_. It is based upon moral character as the highest aim, and upon a correlation of studies which attributes a high moral value to historical knowledge and consequently places a series of historical materials in the center of the school course. The ability of the school to affect moral character is not limited to the personal influence of the teacher and to the discipline and daily conduct of the children; but instruction itself, by illustrating and implanting moral ideas, and by closely relating all other kinds of knowledge to the historical series, can powerfully affect moral tendency and strength. If historical matter of the most interesting and valuable kind be selected for the central series, and the natural sciences and formal studies be closely associated with it, there will be harmony and union between the culture elements of the school course.