A diagram for grammatical analysis is, then, nothing more than a map or chart that makes a subject easier to grasp in its entirety. A diagram in grammar bears about the same relationship to grammar that a map bears to geography, that a drawing of a piece of apparatus in a laboratory manual bears to chemistry, that a chart bears to some aspect of economics in a treatise on that subject. A diagram is ever a means of giving pictorial representation to analysis and is never an end in itself. Because