Columbia subject headings:
Agricultural colleges--United States--History--19th century.
Agricultural experiment stations--United States--History--19th century.
Agriculture--Research--United States--History--19th century.
Agriculture--United States--History--19th century.
Agriculture--United States--Societies, etc.--History--19th century.
Agriculturists--United States--History--19th century.
Farmers--United States--History--19th century.
United States. Department of Agriculture--History--19th century.
Harvard subject headings:
Agricultural colleges--United States--History--19th century.
Agricultural experiment stations--United States--History--19th century.
Agriculture--Research--United States--History--19th century.
Agriculture--United States--History--19th century.
Agriculture--United States--Societies, etc.--History--19th century.
Agriculturists--United States--History--19th century.
Farmers--United States--History--19th century.
United States. Department of Agriculture--History--19th century.
Princeton subject headings:
Agricultural colleges--United States--History--19th century.
Agricultural experiment stations--United States--History--19th century.
Agriculture--Research--United States--History--19th century.
Agriculture--United States--History--19th century.
Agriculture--United States--Societies, etc.--History--19th century.
Agriculturists--United States--History--19th century.
Farmers--United States--History--19th century.
United States. Department of Agriculture--History--19th century.