Scholars of history should know about the Reader's Guide to Periodical Literature. The library has v. 1 from 1896 to the 1990's located in the Bound Periodicals on the top floor. Use the older issues of the Reader's Guide to locate articles published in popular magazines. For example, if you want to read an article from 1898 about the Spanish War, use the 1898 index to find citations to articles covering the war. You may need to use Interlibrary Loan to obtain the article.
Google Scholar is useful to check for the full text of an article. Before submitting an Interlibrary Loan request for an article, do a quick title search in Google Scholar to check for the full text.