Topic
- Canada, Western 43
- Mooring of ships 42
- Aerial photographs 41
- Transportation 35
- Bridges 34
- Rapids 34
- Dwellings 32
- River surveys 32
- United States. Congress--Records and correspondence 32
- Water resources development 32
- Canals--Design and construction--Costs 30
- Dams--Design and construction 30
- Steam 29
- Indian reservations 26
- Landscapes 26
- Dams 25
- River channels 23
- Formations (Geology) 22
- Men 22
- Steamboats 22