Coherence in the Expository Paragraph

In our study of the descriptive paragraph, we laid stress upon the two great principles of unity and emphasis. In our work on the expository paragraph we shall add to these another fundamental law of composition, that of coherence or the arranging of sentences in a paragraph so as to indicate their logical relation. In exposition this relating of one sentence to another is more of a problem than in narration and description. As statement is related to statement by coordinate conjunctions in the com¬pound sentence, and by subordinate conjunctions in the complex sentence, so the sentences which make up an expository paragraph, though independent in form, must in thought stand to each other in either the coOrdinate or subordinate relation.