Subject
- Copper alloys1
- Copper industry and trade1
- Copper--Assaying1
- Copper--Properties1
- Copper--Refining2
- Copper-nickel alloys1
- Corwin, Thomas, 1794-18652
- Crop rotation1
- Crucibles1
- Cuyler, Theodore L. (Theodore Ledyard), 1822-19091
- Dana, James Dwight, 1813-18956
- Davis, William Morris, 1850-19341
- Delaware Geological Survey5
- Doctor of laws degree4
- Du Bois, Patterson, 1847-19171
- Du Bois, William E. (William Ewing), 1810-18813
- E.I. du Pont de Nemours & Company4
- Emoticons1
- Employees--Training of1
- Employment references1