BISMUTH 349 



excellent cliohis for stereotype, of 3 lead, 2 tin, and 5 bismuth an alloy -which molts 

 at 109 F. This compound should bo allowed to cool upon a piece of pasteboard till 

 it becomes of a doughy consistence, before it is applied to the mould to receive the 

 impress of the stamp. This alloy is also used for the metallic pencils for writing on 

 the prepared paper of pocket-books. 



The employment of plates of fusible metal as safety rondelles to apertures in the 

 tops of steam boilers was proposed in France, on the assumption that they would melt 

 and give way at elevations of temperature under those which would endanger the 

 bursting of the vessel, the fusibility of the alloy being proportioned to the quality of 

 steam required for the engine. It has been found, however, that boilers, apparently 

 secured in this way, burst, while the safety discs remained entire ; the expansive force 

 of the steam causing explosion so suddenly, that the fusible alloy had not time to 

 melt or give way. 



Bismuth is interesting as being a highly diamagnetic metal. The distinction 

 between magnetic and diamagnetie bodies was established by the late Dr. Faraday. 

 This may be familiarly explained, by stating that one class of bodies is influenced 

 by magnets, as iron is. being magnetic. That is, if a bar of iron was hung up 

 between the poles of a horse-shoe magnet, it would arrange itself along the lino which 

 unites the two poles ; which line has been called the axial line. But if another 

 class of bodies be selected, bismuth being at the head of this class, and suspended 

 in the same way between the poles of the magnet, they arrange themselves across 

 the axial line, or, as Faraday has termed it, equatorially, these bodies being called 

 in distinction diamagnetic bodies. See MAGNETISM, for a further account of these 

 phenomena. 



The mines of Schneeberg produce annually about 4,000 kilogrammes of metallic 

 bismuth ; those of Johanngeorgenstadt and the cobalt mines of Saxony, about 600 

 kilogrammes equal to about 10,500 avoirdupois pounds. 



In 1844 bismuth was sold at from lOd. to 2s. the pound ; in 1872 it had reached 

 the high price of 30s. the pound ; for some time this price was maintained. Up 

 to 1844 a large quantity of bismuth was produced in this country from cobalt ores in 

 the old way of refining, but a new method was then introduced which necessitated the 

 loss of nearly all the bismuth. In 1845 there was a large demand for a composi- 

 tion to make rollers for calico-printers, which advanced the price. In 1858 the supply 

 began to fall off, and in 1861-2 there was an increased demand for this metal for 

 medicinal purposes, but there has been recently a considerable reduction. A company 

 was formed in London, under the guidance of a German, who professed to have the 

 secret of transmuting the baser metals into gold. This company had works in the 

 Belvedere Road, Lambeth, and as bismuth was considered essential in the process, 

 they bought all they could lay hands on. This, it is believed, more than anything 

 led to the rapid increase in the price of the metal. The supply of bismuth is in but 

 very few hands, and great care is taken to prevent any excess over the demand from 

 coming into the market ; by this means the price is kept up. 



Solid compounds of bismuth, when heated before the blowpipe with carbonate of 

 soda and charcoal, yield a bead of metallic bismuth, surrounded by an incrustation of 

 yellow oxide. Salts of bismuth in solution are recognised by becoming milky white 

 when diluted with water, owing to the formation of sparingly soluble basic salts. 

 These basic precipitates may be distinguished from similar sub-salts of antimony by 

 being insoluble in tartaric acid, and by becoming black when acted on by sulphuretted 

 hydrogen. 



In ' Watts's Dictionary of Chemistry ' will be found various methods for the 

 determination of bismuth. The following processes, however, appear so useful as to 

 warrant their insertion in this place : To detect small quantities of lead in bismuth, 

 or in bismuth compounds, Chapman brings the somewhat flattened bead, reduced 

 before the blowpipe, in contact with some moist basic nitrate of teroxido of bismuth, 

 when, in a short time, in consequence of the reduction of the bismuth by the lead, 

 arborescent sprigs of bismuth are formed around the. test specimen. Since zinc and 

 iron interfere with this reaction, they must bo previously removed, the former by 

 fusion with soda, the latter with soda and borax, in the reducing flame. 



Lead and bismuth can easily be quantitatively separated from each other by the 

 following method, proposed by Ullgren : The solution of the two metals is pre- 

 cipitated by carbonate of ammonia, and the carbonates are then dissolved by acetic 

 acid, and a blade of pure lead, the weight of which is ascertained beforehand, is 

 plunged in the solution. This blade must be completely immersed in the liquor. 

 The vessel is then corked up, and the experiment is left for several hours at rest. 

 The lead precipitates the bismuth in the metallic form. When the whole of it is 

 precipitated, the blade of lead is withdrawn, washed, dried, and weighed. The 

 bismuth is collected on a filter, washed with distilled water which has boon pre- 



