There are three, actually.
To the "souls of the future":
I wander lonely before me on this planet earth,
All yearning long since gone, and life;
To share my innermost there is no companion,
There never was a soul who understood.
I flee the world, it's pleasures too,
And it's people are distant to me now;
Their joys foreign to my distress;
I wander lonely as if upon a star.
And my soul, heavy to burst,
Mute sensuality is not enough,
What it needs is found in song,
And this I am burying in my book.
This will keep you faithfully into an age,
From souls who understand you not in this life,
Till one day, following lengthy years of change,
These songs, blooming, do revive.
Pretty powerful, eh? My book says that she wrote poems enough to cover 600 pages!

Wish I could see those!