8*2 natural history. (Minerals.) [north 
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, Sec. 
— Also the pyrophysalite from Fahlun in Sweden, and the pycnite, 
formerly considered as a variety of beryl, are referable to topaz ; — 
the chondrodite (maclurite, brucite)from New Jersey, and from Pargas 
in Finland ; and some varieties of mica and lepidolite, (Case 32,) likewise 
contain fluoric acid. 
Case 59 contains the chlorides. — Chloride of sodium {muriate of soda), 
or rock salt : the most interesting specimens here deposited of this im- 
portant mineral substance are, the crystallized varieties ; the massive and 
fibrous coloured varieties, the red, chiefly from Hallein in Tyrol, the 
blue and violet from Ischel in Upper Austria ; the stalactical rock salt from 
Mexico, &e Chloride of ammonium or sal-ammoniac, from Vesuvius, 
Saint Etienne en Forez, &c. — Chlorides of lead : to these belong — the 
cotunnite from Vesuvius ; the mendipite or basic muriate of lead from 
Mendip ; and the murio-carhonate of lead from Matlock in Derbyshire, 
of which most rare substance a very perfect suite of specimens will be 
found in this glass Case Chloride of copper or atacamite , in crystallized 
splendid groups, chiefly from Remolinos, Soli dad and Veta negra della 
Pampa larga, in Chili ; — 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 crystallized and laminar varieties for the purpose of using the sand 
(arenilia) in lieu of blotting paper Chloride of silver, called also 
horn-silver and corneous silver : amorphous, botryoidal, in laminae, 
and crystallized in minute cubes and octahedrons, from Veta Negra in 
Chili, the Saxon Erzgebirge, &c Chloride of mercury, or horn- 
quicksilver, with native mercury from Mo schel-Landsberg, Almaden, &c. 
Cases 60 and 60 A contain 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 beds of brown 
coal at Artern in Thuringia; and the oxalate of iron, formerly known by 
the name of resinous iron, but to which that of humboldtite or oxalite is 
now generally given With these is also placed the struvite, a recently 
formed phosphate of magnesia and ammonia, discovered in innumera- 
ble crystals on laying the foundation of St. Nicholas’s church, at Ham- 
burg, in 1845. — To the resins are referred — the amber, of the varieties of 
-which a considerable suite is deposited, many of them inclosing 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 ox petroleum, to the solid and hard asphalt 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 
