<3N Tllf. ^9 



Mosaic Gold. - Facts ^nd Ob- 



ff a rtilxtufe of tin, sal ammoniac, and sulphur be heated'tin ^aJ \<.a 

 together, it happens at the moment the InttfeF is deGO-niposedcoui-oitiKls. 

 that the muriate of tin, whicli is formed, seixes part of its 

 oxide, and transforms it into mosaic gold. But as the. am- 

 moniaCj in proportioa as it is set at liberty, saturates the ncsv 

 products, and disguises the results, we shall resume this ex- 

 periment in a different manner. 



Muriate of Tin ^n(jl $ulphcr, 

 I'M muriate is first to be concentrated to the minimun, 

 even till it congeals. The aqueous product of this by distil- 

 lation cpntains m.uriate at the maximum. Thi« happens be- 

 cause the latter is more volatile than the muriate 9,t the mini- 

 tfium. Distillation is therefore a mean whereby the minor 

 mgiiate may be purified from that w^ose oxidation bus been 

 increased by the atmosphere. The minor muriate is also 

 volatile ; but it requires a much higher temperature than the 

 ojyb^r : this is demonstrable by the process for making tL*e 

 Himing liquor. The muriate at the maximutn is raised by 

 a very gentle heat; whilst the muriate at a minimum Re- 

 mains in the retoit : this is their difference* 



Flowers of Sulphur arc next to be cast into the congealed 

 muriate, and heat gradually applied. In a few seconds vola- 

 tile fuming muriate will pass over in considerable quantity. 

 The excess of sulphur will fix about the neck of the retort, 

 and at the bottom will app-ear a light mass of brilliant mosaic 

 gold, and part spangle the dome of the vessel with gold- 

 coloured flowers. 



On an attentive examination of these products, it will be 

 <!iscovered, — 



1, That the muriate of tin is divided into two parts. 



2, That one of these is deprived of all its acid in favour of 

 tlie other. 



3, That it also parts with some of its oxigen, which raises 

 the other to the quality of fuming volatile muriate. 



4, That tin oiided to the minimum, combines with sulphur 

 only Ln proportion to a certain reduction, wiiich take^ 

 pi;i.ce in the quantity of its oxigen^ : this reduction may hence- 

 forth be considc-ed as subject ;o a Jlxcd dc^^rce, in coinmoa 



With 



