Aachen, Dutch Aken), a city and spa of Germany, in the kingdom of Prussia, situated in a pleasant valley, 44 m.
Krebs, Zur Kritik Alberts von Aachen (Munster, 1881); B.
Kugler, Albert von Aachen (Stuttgart, 1885); M.
See Quix, Geschichte der Stadt Aachen (1841); Pick, Aus Aachens Vergangenheit (Aachen, 1895); Bock, Karts des grossen Pfalzkapelle (Cologne, 1867); and Beissel, Aachen als Kurort (1889).
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.