An important feature of the Elementary Treatise, therefore, is that it does not contain Maxwell's famous equations. In Chapter VI, article 93, Maxwell writes "we may proceed by mathematical methods" or we may employ "the humbler method of actually drawing tentative figures on paper and selecting that which appears least unlike the figure we require." He continues, "I have therefore drawn several diagrams of systems of equipotential surfaces and lines of force, so that the student may make himself familiar with the forms of the lines." These are contained on a series of full page plates bound at the back of the book.