Henning Calvör, director of the mining academy in Clausthal,
also wrote theological and historical works; he was, however, better
known for his major work on mining.
This book presents the state of mining technology in the 18th century
in an impressive way. It is unique among books of this time in that
it provides an abundance of information about the use of machines,
the construction of shafts and mines and the extraction and processing
of ores in the upper Harz region, then one of the most important
mining areas in Germany.