The work may be continued in this way, the secondary text supplying the weekly problem, or the teacher may cut loose from the text and supply graded problems that increase in difficulty. In the latter case, the class should be supplied with the problem, the sources (two or three) and such biographical data as will enable the pupils to criticise the sources. Take each source up in turn and require written answers, with citation of proof, to the following questionnaire: 1. Is this source genuine? 2. Who wrote it and when and where was it written? 3. How much of it is first-hand evidence and how much second-hand, i. e., how much did the witness see and hear himself and how much did he get from some other person? 4. What is the value of the source as a whole, judged by the character of the source (speech, letter, newspaper, pamphlet, song, poem, etc.), the personality of the witness (intellectually and morally) and the time and place of making the records. 5. Make a note of what the witness affirms concerning the event (interpretation.) Let the independent criticism of the sources be followed by a comparison of them to learn whether or not they are independent. Finally, request the pupils to bring together under one head the affirmations of the different witnesses on the point under investigation and endeavor to determine by a comparison of their statements what the truth is. The result should be formulated in writing in the shape of a definite assertion, if the agreement of the independent witnesses justify us in regarding the fact as certain; otherwise it should be represented simply as probable. Specific Illustration--Salamis. As a specific illustration, take the extracts on the battle of Salamis given in my “Source Book of Greek History” (pp. 118-127). Here are three sources, Æschylus’ “Persians,” Herodotus’ “History” and Plutarch’s “Life of Themistocles,” containing almost all the information we possess upon the portion of the battle dealt with in the source book. The extracts are accompanied by the following questions that should be answered in writing by the pupils and form the foundation of the classroom exercise: “1. Compare the three accounts of the battle of Salamis given by Æschylus, Herodotus and Plutarch, noting in what they agree and in what they disagree. Are they independent? 2. Which account is the most valuable, and why? 3. Point out the myths in these accounts, i. e., things that could not have happened. 4. Make an outline of the battle, using the sources, and write a brief narrative, citing the sources. Where they disagree, explain why you follow one source rather than another.”