B 1 S 



460 



B I 



Cornwall : Schnccbera and Johann-Georgen*tadt in Saxony ; 

 and Joachimsthal in Bohemia. 



HISMUTH-GLANCE. This mineral occurs in four-sided 

 prisms of unknown dimensions, but it is stated by Phil- 

 lips to have angles about 91 and 89. It is further cha- 

 racterized by its metallic lustre, and lead-grey approach- 

 it);; ttMt-gNJ* colour, and from its possessing a perfect 

 je in the direction of the short diagonal, and one less 

 perffct in the direction of the base. According to Mohs 

 the hardness if between 2 and 2'5, and the specific gravity 

 6-549. It also occurs massive of n granular composition, 

 or columnar, the individual* being long and straight, and 

 aggregated in various directions. According to the analysis 

 of H. Rose of a specimen from Reddarhyttan, it is thus 

 composed : 



Sulphur . . 18-49 . . 1872 



Bismuth . . 81-51 . . 80-98 



which denotes a compound expressed in the notation of 



Berzclius by Hi. 



Before the blow-pipe sulphur is first driven off, which is 

 followed by a sublimate having the odour of tellurium, 

 and afterwards the characters arc the same as those of the 

 other minerals of bismuth. 



The other minerals will be found described under the 

 names of Needle-ore and Tellurbismuth ; but it may be as 

 well to state, that according to Berzelius, there exists another 

 sulphuret of bismuth, composed of one atom of each of its 

 constituents, a mineral found in the Gregers Klack, Bisp- 

 bcrg, which has hitherto been considered as pure bismuth. 



BISMUTH, a metal mentioned by Agrieola about 1529, 

 but first shown to be a peculiar one 'by Stahl and Dufay : 

 this metal generally occurs native, sometimes combined 

 with sulphur, but rarely with oxygen, in Saxony, Bohemia, 

 and Transylvania. Bismuth is of a reddish white colour, 

 its lustre is' considerable, and its structure lamellated: it is 

 so brittle as to be easily reducible to powder, when cold ; its 

 density is 9'83, which by cautious hammering while warm 

 may be increased to 9'88 ; it melts at 462 according to 

 Daniell, at 476 by Dr. Irvine's experiments, while Mr. 

 Crichton, jun. makes its fusing point 497. At a high tem- 

 perature this metal is volatilized, may be distilled in close 

 Is, and solidifies in foliated crystals; if it be merely 

 melted in a crucible and cautiously cooled, it crystallizes in 

 well-defined cubes. 



Bismuth as met with in commerce is not pure, for it ge- 

 nerally contains iron and arsenic, and probably tome ottier 

 metals ; in order to purify it, it is to be dissolved in nitric acid, 

 the solution is to be decomposed by water, and the preci- 

 pitate, after being boiled in a solution of soda, is to be mixed 

 with black llux, and moderately heated in a crucible. 



Oxygen and Bismuth, combine in at least two propor- 

 tions, forming the protoxide and peroxide. When this metal 

 is heated to whiteness in the air it takes fire and burns with 

 an obscure blue (lame, and is converted into a yellow pow- 

 der, which is the protoxide of bismuth, composed of 

 1 equivalent of metal . . .71 



1 do. of oxygen . . 8 



1 do. protoxide , . "9 



When the steam of water is passed over ignited bismuth 

 the metal is not oxidized, and consequently the water is not 

 decomposed by this process. The best method of preparing 

 the protoxide is to dissolve the metal in nitric acid, to dc- 

 romposc the solution by water, and calcine the precipitated 

 ubnitralc in a crucible. The resulting oxide is of a straw 

 colour, is insoluble in water, but readily dissolved by acids, 

 and is the only oxide of this metal which forms salU with 

 the-.n. Neither potash nor soda nor their carbonates dis- 

 solve this oxide, nor does ammonia, but the carbonate 

 takes up a little of it. 



of Ritmuth is obtained by heating the prot- 

 oxide with a solution of chloride of lime or soda ; the 

 ebullition must be continued for a considerable time. The 

 oxide nf liisrniith assumes at first a fine ochre yellow colour, 

 and at length it becomes deep brown; it is then to be well 

 washed, and in order to separate any protoxide which may 

 remain, it i* to be treated with cold nitric acid, diluted with 

 nine parts of water ; this it to be added in excess, to prevent 

 the formation of tmbnitratc of bismuth ; it is then to be 

 washed, at first with weaker acid, then water, and to be 

 Uricd by a gentle heat. The peroxide thus prepared is a 

 heavy deep brown powder, strongly resembling peroxide of 



lead; when heated to about 600 it is decomposed, oxygen 

 gas if evolved, and yellow protoxide of bismuth remain*. 

 It forms no compound with any arid ; from muriatic acid it 

 evolve* chlorine, by hydriodic acid it is converted into a fine 

 brown iodide, and the liquor become* yellow, owing to the 

 presence of free iodine ; other acids, under various circum- 

 stances, evolve oxygen from it. The fixed alkalies and 

 ammonia produce no effect upon it ; the loss of weight inch 

 it suffers by being merely heated shows that it is composed of 



2 equivalents of metal . . . l .: 



3 do. oxygen . . .24 



equivalent . . 166 



or it may be regarded as a sesquioxide, composed of 7 1 = 1 

 eq. metal-fl2 = 14 eq. of oxygen. 



According to Berzelius there exists also a suboxide of 

 this metal, but it is most probably a mere mixture of tin- 

 protoxide and the metal. 



Chlorine and Bismuth combine in two proportions at 

 least. The protochloride may be obtained by dissolving the 

 protoxide in concentrated muriatic acid, and evaporatiiu 

 liquor to the point of crystallization. This salt is colourless 

 and volatile, so that it may be distilled ; it was formerly 

 called butter of bismuth ; when heated it flows like oil, but 

 it solidifies on cooling. This compound may also be prepared 

 by heating one part of powdered bismuth with two parts of 

 perchloridc of mercury ; the results are protochlorides of 

 both metals. It is composed of 



1 equivalent of metal . . .71 



1 do. chlorine . . 35 



equivalent . . 106 



When a neutral solution of nitrate of bismuth is poured into 

 a concentrated solution of common salt, a subchloride of 

 bismuth is precipitated or probably an oxychloride ; it was 

 formerly employed as a cosmetic under the name of magis- 

 tery of bismuth. Its exact composition has not been de- 

 termined. 



Fluorine and Bismuth form a fluoride which is soluble in 

 water and which precipitates during evaporation in the state 

 of a white powder. 



Bromine and Bismuth combine to form the bromide when 

 the metal in powder is heated in the vapour of bromine in 

 a long tube closed at one end ; excess of bromine must be 

 employed ; the combination is effected without any evolu- 

 tion of light. Yellow vapour arises and condenses on the 

 sides of the tube, and the compound remains at the bottom 

 of it. The yellow vapour probably contains less bismuth than 

 the more fixed bromine, which appears to be composed of 

 1 equivalent of bromine, . . 80 

 1 ditto bismuth, . . 71 



equivalent 151 



This bromide is of a steel grey colour, and fuses at about 

 392, when it becomes of a hyacinth red colour, but it returns 

 to the grey on cooling ; by exposure to the air it absorbs 

 moisture and is rendered yellow ; a large quantity of water 

 decomposes it, and there is formed a sub-bromide of bis- 

 muth, which separates, while hydrobrornic acid combined 

 with a little oxide of bismuth remains in solution. 



Iodine and Bismuth readily combine with the assistance 

 of heat, when the metal is finely powdered ; this iodide has 

 a deep orange colour : it is insoluble in water, but is dissolved 

 by potash : it is probably composed of 



1 equivalent of iodine . . . 126 

 1 ditto bismuth ... 71 



equivalent . . . 197 



When a solution of chloride of bismuth is gradually 

 dropped into a weak solution of iodide of sodium, a chesmit co- 

 loured precipitate is formed, which appears to bo a subiodidc. 

 Sulphur and Bismuth occur in combination and crys- 

 tallized at Reddarhyttan in Westmanland, and they very 

 readily combine and form a sulphuret which has a metallic 

 lustre and a crystalline texture; it is not very fusible, and 

 its density is 7'501. Sulphuretted hydrogen throws down 

 black sulphuret from the solutions of this metal, ami alcn 

 converts its oxide into sulphuret. Sulphuret of bismuth 

 is composed of 



1 equivalent of bismuth . . . 71 

 1 ditto sulphur . . 16 



equivalent 





