1820.] Chromate and Bichromate of Potash. 323 



colour, and the acid appears to be deprived of a portion of its 

 oxygen. One hundred grains of chromate of potash when kept 

 for half an hour in a red heat lose 3-2 grs. of their weight. This 

 loss is probably owing to water, which does not seem chemically 

 combined, but only mechanically mixed with the layers of which 

 the crystals are composed. 



The following table exhibits the effects produced by a pretty 

 strong solution of chromate of potash in water when mixed with 

 solutions of different salts. 



1. Sulphate of Copper. — A reddish-brown precipitate. 



2. Sulphate of Zinc. — Light-yellowish flocks appear at first 

 redissolved by agitation ; but on adding more chromate of pot 

 ash, they become permanent. 



3. Muriate of Alanganese. — Colour becomes darker and red- 

 der ; but no immediate precipitate falls. After an interval of 24 

 hours, a black sediment makes its appearance. 



4. Nitrate of Mercurij. — A fine red precipitate. Scarlet, 

 when dry. 



5. Pernifrate of Iron. — Becomes nearly the colour of muriate 

 of platinum; but no precipitate appears after two days. 



6. Protosulphate of Iron. — A copious brown flocky precipitate 

 like that from sulphate of copper. 



7. Nitromuriate of Gold. — No change after standing two days, 



8. Nitrate of Silver. — A copious dark-red precipitate^ 

 Brown, when dry. 



9. Muriate of Platinum. — A copious dark-red precipitate, 

 similar to that from nitrate of silver. Brick-red, when dry. 



10. Soda-muriate of Rhodium. — 0. 



1 1 . Sulphate of Nickel.— 0. 



12. Sulphate of Cobalt. — 0. 



13. Muriate of Antimoni/, with Excess of Acid. — A dark- 

 green precipitate, redissolved on agitation. The liquid assumes 

 a fine green colour. 



14. Hi/drosulphuret of Soda-and- Antimony. — A precipitate in 

 yellow flocks. 



15. Tartar Emetic. — No immediate change; but a slight 

 precipitate in 24 hours. The liquid assumes a dirty-greenish 

 yellow colour. 



16. Nitrate of Bismuth. — A white precipitate redissolved by 

 agitation. A copious yellow precipitate on the addition of water. 



17. Muriate of Tin. — A verv copious flocky precipitate of a 

 yellowish-brown colour. Black, when dry. 



18. Nitrate of Bari/tes. — A copious yellow precipitate. 



19. Muriate of Strontian. — Ditto, rather darker coloured. 



20. Nitrate of Lime. — A slight yellow precipitate, whicii 

 gradually increases, and adheres to the sides and bottom of the 

 vessel. 



21. Lime Water. ~0 



X 2 



