1811.] Chromic Acid with different Bases. 425 



1 . Chromate of Soda. 



Chromic acid neutralized with soda forms a dark yellow solution, 

 which by spontaneous evaporation forms thin six-sided tahles with 

 two long and four short faces. They are transparent, easily soluble 

 in water, and do not alter vegetable blue colours. They are not 

 entirely insoluble in alcohol, but require a considerable proportion 

 of that liquid to dissolve them. 



2. Chromate of Potash. 



Chromic acid dissolves potash, and at the same time lets fall a 

 small quantity of green oxide.* The orange-coloured solution has 

 a great tendency to efflorescence, especially when little pieces of 

 wood are introduced into it. 



Chromate of potash, when rapidly evaporated, forms a yellow 

 saline mass ; when more slowly evaporated, it forms four-sided 

 tables ; they are not altered by exposure to the air, are transparent, 

 and have an Aurora-red colour. 



3. Chromate of Ammofiia. 



This compound effloresces, and forms dendritical crystals, while 

 a brown powder separates, which is oxide of chromium. It is 

 formed in consequence of the decomposition of the chromic acid by 

 the ammonia, and appears as often as the salt is dissolved in water, 

 and allowed to effloresce. When this salt is exposed to a red heat, 

 it is completely decomposed. 



4. Chromate of Glacina. 



Glucina thrown down by carbonate of potash was dissolved very 

 slowly by concentrated chromic acid; the solution has a yellow 

 colour, and does not seem capable of crystallizing. 



5. Chromo-Sidphate of Glucina. 



When sulphate of glucina is poured into chromic acid, the 

 appearance of the solution is not altered ; but when the liquid is 

 evaporated, there remains behind a triple salt in dendritical crystals 

 in a state of efflorescence. 



G. Chromate of Yltria. 



Chromic- acid dissolves yttria, cold, in considerable quantity, and 



with effervescence. The solution has an astringent and pungent 



, and, like most of the eliminate-., has an orange-red colour 



ing into yellow. The .solution is quite neutral. Chromate of 



yttria gives by evaporation dendrites, which are composed of very 



• Thii oxide waa wnlimit douhi ili. olved in the chromic arid, and owed id 

 itloi i'i some accident, probably tin- nitration of the acid through paper. 

 When tin, green oxide i^ teparautd i • \ the Alter, no new precipitate appear*. 

 Ammonia, on the contrary, prccipitatei tin; chronic acid. 



