What does "Geheimer Regierungsrat (at Trier)" mean? And what does empyreum mean?

Context:

The Difference Between the Democritean and Epicurean Philosophy of Nature.
with an Appendix

Dedication

To his dear fatherly friend,

Ludwig Von Westphalen,

Geheimer Regierungsrat

at Trier,

the author dedicates these

lines as a token

of filial love

You will forgive me, my dear fatherly friend, if I set your name, so dear to me, at the head of an insignificant brochure. I am too impatient to await another opportunity of giving you a small proof of my love.

May everyone who doubts of the Idea be so fortunate as I, to be able to admire an old man who has the strength of youth, who greets every forward step of the times with the enthusiasm and the prudence of truth and who, with that profoundly convincing sun-bright idealism which alone knows the true word at whose call all the spirits of the world appear, never recoiled before the deep shadows of retrograde ghosts, before the often dark clouds of the times, but rather with godly energy and manly confident gaze saw through all veils the empyreum which burns at the heart of the world. You, my fatherly friend, were always a living argumentum ad oculos [visible proof]. to me, that idealism is no figment of the imagination, but a truth.

I need not pray for your physical well-being. The spirit is the great physician versed in magic, to whom you have entrusted yourself

More:
http://www.marxists.org/archive/marx/works/1841/dr-theses/dedicati.htm
http://www.marxists.org/archive/marx/works/1841/dr-theses/