Columbia subject headings:
Humboldt, Alexander von, 1769-1859--Correspondence.
Mendelssohn family--Correspondence.
Scientists--Germany--Correspondence.
Harvard subject headings:
Humboldt, Alexander von, 1769-1859--Correspondence.
Mendelssohn family--Correspondence.
Scientists--Germany--Correspondence.
Princeton subject headings:
Humboldt, Alexander von, 1769-1859--Correspondence.
Mendelssohn family--Correspondence.
Scientists--Germany--Correspondence.