1. A subterraneous passage from which coal, metals, metallic ores, are obtained.
Depth of Mines.Feet.
Eselchact, Bohemia (silver).3,778
Dunkenfield, England (coal)2,504
Pendleton, England (coal)2,504
Linden, Prussia (salt well)2,331
Tresavean, England (copper)2,112
Durham, England (coal)1,773
Valenciana, Mexico (silver)1,686
Crown Point, Comstock lode, Nevada (silver)1,400
Santa Rosa, Mexico (silver)1,200
2. Crude ironstone, known as raw-mine, greester shall be able to play them upon the organ, harpsichord, etc. (Phil. Tran., 1747.) Creed invented a machine for this purpose in England in 1747; Hennersdorf of Berlin, one in the following year.
John Freke in England, Unger and Hohlfield in Prussia, worked at the idea.
Unger formed a part of the harpsichord.
The device of Hohlfield was attachable to any instrument.
Descriptions were transmitted to the Academy of Berlin in 1752, and published in Brunswick in 1774.