According to a calculation made by P. Frech in 1900, on the basis of the then rate of production, the coalfields of central France, central Bohemia, the kingdom of Saxony, the Prussian province of Saxony and the north of England, would be exhausted in 100 to 200 years, the other British coalfields, the Waldenburg-Schatzlar and that of the north of France in 250 years, those of Saarbriicken, Belgium, Aachen and Westphalia in 600 to Boo years, and those of Upper Silesia in more than 1000 years.
In the 10th century learning flourished at Aachen under Bruno, brother of Otto I.
Krabe of Prummern near Aachen, the most scientific and practical of German cultivators, the results of whose experiments have been published in his admirable Lehrbuch der rationellen Weidenkultur (Aix-la-Chapelle, 1886, et seq.) went so far as to assert that willows prefer a dry to a wet soil.
Besides going to Aachen for the coronation, he made excursions down the Rhine from Cologne to Nijmwegen, and back overland by 's Hertogenbosch; to Brussels; to Bruges and Ghent; and to Zealand with the object of seeing a natural curiosity, a whale reported ashore.
Charles was crowned at Aachen, 23rd of October 1520, and opened his first German diet at Worms, 22nd of January 15 21.