geography: What plant is a national emblem of Wales?

Questions

In 1749 Johann Nikolaus---------- , musicologist and first biographer of Bach, born.?

In 1784 Empress of ---------- sets sail on first New York to China route.?

In 1810 Frederic---------- , composer, born.?

In 1857 Lord Robert---------- , founder of the Boy Scouts, born.?

In 1892 Edna St. Vincent---------- , poet, born.?