Each of our primary source databases contain different types of materials, and they have different geographic, chronological, and thematic foci.
In small groups, search the term "salt trade" in the following databases. When possible, limit the results to pre-1776 publications. Consider:
Using Sabin again, still limiting to pre 1776, search just salt instead of "salt trade"
Using the main catalog again, search Salt AND trade, and set publication date to 1500 to 1776.
See how the slight change in wording changes the results.