Perhaps you should try some spelling variations:
"royal meteorological instruments" » "royal meteorological measurements", "local meteorological instruments", "real meteorological instruments", "global meteorological instruments"
"road meteorological instruments" » "road meteorological measurements", "ray meteorological instruments", "real meteorological instruments", "world meteorological instruments"

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"royal meteorological instruments\") OR (\"road meteorological instruments\"))".
• Removing quotes may allow a broader search: (( royal meteorological instruments ) OR ( road meteorological instruments )).
• Adding a wildcard symbol may retrieve word variants: (("royal meteorological instruments") OR ("road meteorological instruments"))*.