56 
NORTH GALLERY. 
[upper 
Div. IV. and tUDgstates, and these, in turn, are followed by the class of 
Cases 51 chromates and the sulphates. The suite of specimens of Perofskite 
and 52. from Siberia, the crystals of Eudyalite, of Columbite, of Fergusonite, 
and of Pyrrhite, and the specimens of Tscheffkiuite, are especially 
observable for their excellence or their rarity. 
Cases 53 to Among the anhydrous species in the sulphates, attention may be 
called to the specimens of Celestine (strontium sulphate) from near 
Bristol, and to the Anglesite (lead sulphate) from Pennsylvania and 
from Monte Poni. Gypsum, or Selenite, the hydrated calcium sul- 
phate, is an important mineral as yielding Plaster of Paris by the 
expulsion of its water, A magnificent specimen of this mineral, as 
remarkable for its size as for the grouping of its crystals, presented by 
His Koyal Highness the late Prince Consort, ornaments a window in 
Koom II. It was found at Reinhard's-brunn, Saxe-Coburg. 
Case 57. Adjoining these are a few minerals of the greatest rarity and inte- 
rest. The crystals of Linarite are unique, and the specimens of Cale- 
donite and Lanarkitfe, of Leadhillite, a lead hypotetracarbouate 
combined with sulphate, and of the rare mineral Connellite, are 
among the finest known of these British species. 
Cases 56 to The borates and the class of nitrates occupy part of Case 56 ; and 
thence to Case 60, the Cases are occupied by the class which includes 
the phosphates and arsenates, in which the isomorphism of the corre- 
sponding compounds of the arsenoid element Phosphorus, and of 
Arsenic, is so complete that the salts of their acids cannot be well 
classified apart from each other. With these also the Vanadates find 
their place, as being isomorphous with them. 
Here may be seen fine crystals of Erythrine, the beautiful cobalt 
arsenate; specimens of Haidingerite (Case 57), and of Erinite (Case 
57); crystals of I^azulite (Case 58); very fine suites of Uranite (phos- 
phate of Copper and Uranium), and of Autunite ; the beautiful blue 
Cornish mineral Liroconite; and splendid specimens of Apatite, 
Case 60. Mimetesite, and Pyromorphite. 
As an Appendix to the Collection, two half Table-Cases in Room I., 
contain certain organic compounds, which as occurring in the earth with 
constant and definite characters, independent of organic structure, find 
their place in a Mineral Collection. Among these. Amber, in ancient 
times ranking in value with the gems, is here exhibited in a large 
series of specimens. 
In Room II. will be seen two half Table-Cases adjoining the wall, 
in which is arranged an extensive and instructive series of pseudo- 
morphous minerals. They illustrate the decomposing influences to 
which many minerals have been subjected, and they throw valuable 
light on the order of succession in which, and the conditions under 
wliich, particular minerals liave been formed and deposited. 
NEVIL STORY-MASKELYNE. 
