Your searching activities in American Memory collections have introduced you to some of the joys and challenges of searching an online archive. Search results differ with the finding aid used. The collections have unique characteristics.
Collections contain surprises.
Collections are not encyclopedic in scope. Searching a historical archive is not like searching Yahoo or a modern library catalog. You need to put yourself in the time frame of the collection to think of good keywords to use in a search. Searching by these labels will not be as productive. Subject terms and cataloging practices change over time as society changes and evolves.