68 
NATURAL HISTORY. 
[north 
den.— Fluoride of sodium and aluminum, called cryolite, found in West 
Greenland: pure and mixed with brown iron stone, Gelena, &c. 
Case 58 A. is appropriated to some of the silicates containing fluo¬ 
rides : — to these belongs the topaz, here illustrated by a considerable 
series of crystals of Saxon, Brazilian, and Siberian varieties, among which 
there are several new modifications; Saxon varieties imbedded in the 
topaz rock, an aggregate of topaz, shorl, quartz, and sometimes mica; 
Brazilian topazes, yellow and pink, imbedded in rock crystal, &c. 
— Also the pyropliysalite from Fahlun in Sweden, and the pycnite, 
formerly considered as a variety of beryl, are referable to topaz; — 
chondrodite (maclurite, brucite) from New Jersey, and from Pargas in 
Finland. 
Case 59 contains the chlorides. — Chloride of sodium fnuriate of soda\ 
or rock salt : the most interesting specimens here deposited of this im¬ 
portant mineral substance are, the ciystallized varieties; the massive and 
fibrous colom*ed varieties, the red, chiefly from Hallein in I'yrol, the 
blue and violet from Ischelin Upper Austria; the stalactical rock salt from 
Mexico, &c — Chloride of ammonium or sal-ammoniac, from Vesuvius, 
Saint Etienne en Forez, &c. — Chlorides of lead: to these belong, the 
cotunnite from Vesuvius; the basic muriate of lead fi'om Mendip ; and 
the murio-carhonate of lead from Derbyshire, of which most rare sub¬ 
stance very perfect specimens will be found in this glass Case. — Chlo~ 
ride of copper or atacamite, in crystallized splendid groups, chiefly from 
Remolinos, Solidad and Veta negra deUa Pampa larga, in Chdi; — what 
was originally termed Peruvian green sand, or atacamite (being obtained 
from the desert of Atacama between Chili and Peru) is now known to 
be artificially produced by pounding the ciystallized and laminar va¬ 
rieties for the purpose of using the sand (arenilla) in lieu of blotting 
paper. — Chloride of silver, called also horn-silver and corneous silver: 
amorphous, botryoidal, in laminae, and crystalhzed in minute cubes and 
octahedrons, from Veta Negra in Chili, the Saxon Erzgebirge, &c — 
Chloride of mercury, or horn-quicksilver, nith native mercury from 
Moschel-Landsberg, Almaden, &:c. 
Case 60 contains a small collection of organico-chemical, or such 
mineralized substances as are composed after the manner of organic 
bodies, from which they derive their origin. They are divided into salts, 
resins, bitumen, and coal. To the salts belong — the mellate of alumina, 
also called mellite or honey-stone, found in the beds of brown coal at 
Arteni in Thuringia; and the oxalate of iron, formerly known by the name 
of resinous iron, but to which that of humholdtite is now generally 
given _ To the resins are referred — the amber, of the varieties of 
which a considerable suite is deposited, many of them enclosing insects, 
&c. ; to which, for the sake of comparison, are added, specimens of re¬ 
cent copal, likewise containing insects ; — fossil copal or Highg ate resin; 
— retinite or retinasphalt, found at Bovey; together with some other re¬ 
lated resinous substances; — the idrialite, to which the bituminous cin¬ 
nabar or brand-ertz is partly referable. To the bitumina belong the 
varieties of mineral pitch of all degrees of consistence, from the fluid 
naphtha and mineral oil or petroleum, to the solid and hard and 
jet or pitch coal; — the elaterite or elastic bitumen of Derbyshire, (a suite 
of specimens exhibiting all degrees of solidity, from that of honey to 
