In the grade of Rhetoric, which is the highest of the literary or classical course, the prelection is double; one is upon the art of eloquence, wherein precepts are explained; the other is upon an author, and has for its object the development of style. Taking up an author such as Cicero, the Professor will, in the first place, make clear the sense of the passage. Secondly, the artistic structure is to be analyzed and demonstrated: the _Ratio_ here details the elements of this analysis. Thirdly, other passages which are similar in thought or expression are to be adduced; other orators and poets, whether in the classics or in the vernacular, are to be cited as employing the same principles of art, in persuading or narrating. Fourthly, if the matter allows of it, the thoughts expressed by the author are to be confirmed by what wise men have said on the same subject. Fifthly, whatever else will conduce to ornamenting the passage is here in place, from history, mythology, erudition of every kind. Finally, the words are to be weighed singly; their propriety of use, their beauty, variety, rhythm to be commented upon. The whole of this treatment, however, does not come within the limits of each and every lesson.[288] The "erudition" for this grade is defined to comprise "the history and manners of nations, the authority of various writers, and all learning, but sparingly, to suit the capacity of the scholars."[289] The prelection on the precepts or rules, "the power of which," says the _Ratio_, "is very great for the purposes of oratory," comprises six points. Cicero is the rhetorician who supplies the precepts; but Quintilian and Aristotle may also be used. First, the meaning of the rule is to be explained. Secondly, upon the same rule, the rhetoricians are to be collated. Thirdly, some reason for the rule is to be expounded. Fourthly, some striking passages from prose writers, and also from poets, are to be adduced in exemplification of the rule. Fifthly, if anything in the way of varied erudition makes to the purpose, it is to be added. Lastly, an indication should be given how this principle of art can be turned to use by ourselves; the style in which this is done must be marked by the most absolute choice and finish of diction possible.[290]