I began to read with avidity, but was utterly mystified.

What emperor was this?
Probably the Tsar or the Emperor of Austria, for there was no German Emperor in those days.

But no! It was evidently the Emperor of the French.

And how did Napoleon get to Wilhelmshohe?
The French must have broken through the Rhine defences, and pushed far into Germany.

But no! As I read further, I found this theory equally untenable.