228 COMBINATIONS O^ OXlMUJlIATIC GA8 AND OXtGEN. 



than those of the fixed otles. The oxides of cobalt and 

 nickel were scarcely acted upon at a dull red heat. The 

 red oxide of iron was not affected at a strong red heat, while 

 the black oxide was rapidly decomposed at a much lower 

 temperature; arsenical acid underwent no change at the 

 greatest heat that could be given it in the glass retort, 

 while the white oxide readily decomposed, 

 Oxigen given ' In cases where oxigen was given off, it was found exactly 

 the"metal\b- *^^ same in quantity as that which had been absorbed by 

 snbed. the metal. Thus 2 grains of red oxide of mercury ab- 



sorbed 0*9 of a cubical inch of oximuriatic gas, and af- 

 forded 0*45 of oxigen*. Two grains of dark olive oxide» 

 from calomel decomposed by potash, absorbed about 0*94 

 of oximuriatic gas, and afforded 0*24 of oxigen, and corro- 

 sive sublimate was produced in both cases. 



Analysis of • I have made two analyses of corrosive s^Ublimate 'and'Calonjeij'tSfitti' 



corrosive sub- considerable care. 1 decomposed 100 grains of corrosive sublimate i>y 

 imate am o 90 grains of hydrat of potash. This aflorded 79*5 grains of orange co-" 

 loured oxide of mercury, 40 grains of which afforded 9-15 cubical iiiche*ofi 

 oxigen gas; the muriate of silver foimed from the 100 grains was 102^^.. 

 100 grains of calomel, decomposed by 90 grains of potash, afForded^S2 

 grains of olive coloured oxide of mercury, of which 40 grains gave by de- 

 composition by heat 4'8 cubical inches of oxigen. The quantity of 

 horrx-silver form«d from the 100 grains was 58-75 grains. 



In the second analysis, the quantity of oxide obtained from corrosive 

 sublimate was 78-7; the quantity of muriate of silver formed was 103.- 4.^- 

 the oxide produced frorh calomel weighed 83 grains ; the Jiorn-silver.. 

 formed was 57^ grains. 1 am inclined to put most confidence in the lasti^ 

 iinalyses 5 but the tenor of both is to show, that the quantity of oximu- 

 riatic gas in corrosive sublimate is exactly double that in calomel, aid- 

 that the orange oxide contains twice as much oxigen as the black, the 

 mercury being considered as the same in all. The olive colour of the ox- 

 ide formed from calomel is owing to a slight admixture of orange oxide, 

 formed by the oxigen of (he water used in precipitationj the tint I find is 

 almost black, when a boiling solution of potash is used; and trituration 

 with- a little orange oxide brings the tint to olive. It has been stated, that 

 the olive oxide thrown down from calomel by potash is a submuriate ; 

 but I have never been able to find a vestige of muriatic acid in it when 

 well washed. It is not easy to obtain peifect jirecision in analyses of the 

 oxides of mercury ; water adheres to the oxides, which cannot be en- 

 tirely driven off without the expulsion of some oxigen* In all my expe- 

 riments, though the oxides had been heated to a temperature above 212, 

 a little dew collected in the neck of the retort^ so that the 40 grains must 

 have been overrated. 



In 



