82 
THE PRINCIPAL FLOOR. 
Zinc. 
Case 21. — On the upper shelves of this Case are some fine' 
examples of the exclusively American ores called Zincite , or red 
oxide of zinc, and Franklinite , a mineral in which the zinc 
oxide is associated with the oxides of iron and manganese, and 
which is valued as an ore of iron rather than of zinc. The New 
Jersey specimens are followed by a group of carbonates and 
silicates of zinc from the celebrated Vieille Montagne or Alten- 
berg deposits. These mines are situated on part of the Belgian, 
Prussian, and neutral territories, between the towns of Aix-la- 
Chapelle and Yerviers. The calamine of these deposits has been 
worked since 1485 ; but for four centuries it was employed 
merely as an earth wherewith to make brass. 
The group of zinc ores is brought to a close by several 
examples of Blende, or sulphide of zinc, of which those from 
Hungary and Bohemia present fine crystalline forms, whilst 
other specimens are notable as containing silver. 
Lead. 
Case 21. — A fuller description of the various minerals from 
which lead is extracted has been given in the notice of the 
British series (p. 74) : the foreign specimens in the case before 
us are interesting, however, for comparison with our own. 
In the group of lead-spars attention should be directed to 
the fine transparent and well-formed crystals of Anglesite , or 
sulphate of lead, and of Cerussite, or carbonate of lead, from the 
Wheatley mine in Pennsylvania, where they occur in the upper 
part of rich lead veins coursing N.E. and S.W. in gneissose 
rocks Nor must we omit notice of the remarkably brilliant 
crystals of anglesite which bestud the cavities in the rich galena 
of Monte Poni, in the island of Sardinia. Of the phosphate of 
lead called Pyromorphite there are exhibited some examples of 
peculiar hollow crystals from the Wheatley mine, and of fine 
barrel-shaped crystals from the mines of Nassau. The eye will 
not fail to be attracted by the brilliant yellow crystals of 
Wulfenite or molybdate of lead, from Utah and Arizona ; and 
here also will be found some sombre specimens of the same 
species from the lead mines of Carinthia. 
A small group of the somewhat rare antimonio- sulphides of lead 
is here intercalated, including the species called Boidangerite y 
Plagionite, and Geocronite ; and from these we pass to the most 
widely diffused ore of lead — its sulphide, called Galena, of which 
mineral a large series of specimens is exhibited, fairly repre- 
senting the principal lead-producing districts of the continent. 
France, Spain, Tuscany, Saxony, Hungary, and Russia have 
each contributed samples, and with these European specimens 
are placed a few lead-ores from certain mines in Asia and 
America. 
