48 EOG-MAXGAKESE. 



from decaying vegetables, which enables it 

 to dissolve the iron in the rocks over which 

 it flows, or over which it stands. The water 

 having reached the lower points of the coun- 

 try, or being poured into hollows, becomes 

 stagnant, by degrees evaporates ; and the 

 dissolved iron being accumulated in quan- 

 tity by fresh additions of water, then follow 

 successive depositions, which at first are yel- 

 lowish, earthy, and of little consistence, and 

 this is Morass-Ore ; but in course of time 

 they become harder, their colour passes to 

 brown, and thus Swamp -oi'e is formed. After 

 the water has completely evaporated, and 

 the swamp is dried up, the swamp-ore be- 

 comes much harder, and at length passes 

 into Meadow-ore, which is already covered 

 with soil and grass." — Jameson's Min., vol. 

 ii. pp. 338-9. 



Brit. Mus., Case 16. 



31. P. G. Principal Floor, Wall-case 19 

 (Foreign). 



Bog-manganese or Wad chiefly consists 

 of oxides of manganese and water, with some 

 oxide of iron, and often silica, alumina, 

 lime or baryta. See Wad. 



Bohemian Diamond. A name sometimes 

 given to limpid and transparentRock-crystal, 

 when cut and polished. 



Bohemian Garnet. See Pyrope and 

 Carbuncle. 



Bohemian Topaz. See Citrine. 



BoHNEKz, Bean-ore. A variety of Li- 

 monite, or hydrous oxide of iron, occurring 

 in spherical or ellipsoidal concretions, which 

 have a concentric lamellar structure. 



31. P. G. Wall-case, 18. 



Bois DE MoNTAGNE, Brochaiit. See 

 Mountain Wood. 



Bois Petrifie. Brochant. Wood-stone, 

 See WooD-OPAL. 



Bole. This substance is closely related to 

 Halloysite in appearance, and particularly 

 so in the large amount of water which it con- 

 tains ; but it is more variable in character. It 

 probably results from the alteration of some 

 felspathic or aluminous mineral, and consists 

 chiefly of hydrated bisilicate of alumina, in 

 which a portion of the alumina is replaced 

 by sesquioxide of iron. From the analysis 

 of Wackenroder it appears to contain either 

 2 or 4 atoms of water, according to the way 

 in which it is dried. It occurs in solid 

 amorphous masses of a brownish, yellowish, 

 or reddish colour, inchning to blackish - 

 brown, has a greasy feel, and adheres strong- 

 ly to the tongue. Tt yields to the nail, breaks 

 with a conchoidal fracture, and has a shin- 

 ing streak; subtranslucent to opaque. In 

 Y/uter it emits a crackling noise, and sepa - 



BOLTOXITE. 

 rates into small pieces with the evolution of 

 air- bubbles. H. 1-5. S. G. 14 to 2. 



BB fuses easily to a yellow or green 

 enamel. 



Analysis, from Capo di Bove, by C. Von 

 Hauer : 



Silica . . , . 45-64 



Alumina . . . 29-33 



Peroxide of iron . . 8'88 



Lime .... 0-60 



Magnesia . , . trace 



Water .... 14-27 



98-72 



Localities. Bole is found in irregular beds 

 or disseminated masses in clayslate and 

 basalt. It occurs at Striegau in Silesia, the 

 Habichtswald in Hessia, near Sienna in 

 Italy. 



Bole is distinguished from Lithomarge 

 by its fusibility and physical characters. It 

 was formerly employed in medicine as an 

 astringent, and is now used as a pigment. 



Name. From /S^yAoj, a clod of earth. 



31. P. G. Horse-shoe Case, No. 1121, 

 Upper Gallery, Table-case B in recess 6, Nos. 

 202 to 204. 



BoLOGNESE Stone. A grey or yellowish - 

 grey variety of Barytes forming rounded 

 masses, composed of minute fibrous crystals, 

 diverging from the centre. It become; 

 phosphorescent when heated, and remains so 

 for some time even after cooling. Bolog- 

 nese phosphorus is made bv mixing the 

 powder of this stone with a little gum, and 

 exposing the mixture to a slight red heat, 

 and afterwards for some time to the light of 

 the sun, when it is found to be phosphor- 

 escent in the dark. It is found in clay at 

 Monte Paterno, near Bologna, whence the 

 nam-e. 



Brit. Mus.. Case 52. 



Boltonite, Shepard, Geo. J. Brush. A 

 variety of Chrysolite. It occurs disseminated 

 in in-egular masses, seldom showing any 

 traces of crystalline form. Colour ash-grey 

 to yellowish-white, the darker colours chang- 

 ing to yellow on exposure to the weather. 

 Lustre vitreous. Fracture uneven or small 

 conchoidal. Fragments colourless and 

 nearly transparent. H. 6 to Q'b. S.G. 3-21. 



Comp. Magnesia-chrj'solite, or R^ Si. 

 Analysis by J. L. Smith : 



Silica 42-82 



Alumina 



Magnesia 



Protoxide of iron . 



trace 



54-44 



1-47 



