A new salifiable Base. 309 
pearance of an earth. It has no taste or smell. 1t is slightly 
soluble in water, alcohol, acids, and alkalies. The impure acid 
- solution is eminently distinguished by its property of giving a very 
fine azure precipitate with triple prussiate of potassa, and which 
may readily be distinguished, after a few experiments, from that 
caused by iron. It may, perhaps, be applicable to dyeing or 
painting. The neutral combination of the substance with acids 
does not give the blue precipitate, it requires for this purpose 
excess of acid. 
This substance combines with various simple bodies. With 
iodine it forms a compound, at common temperatures, of a dull 
yellow colour, resolved by heat into its two principles. When 
fused with sulphur they unite together ; its compound with phos- 
phorus is of a fine red colour, and, when dissolved in water, oc- 
casions the formation of phosphuretted hydrogen, and a phos- 
phate. 
This substance has extraordinary powers of resisting heat. It 
might be taken for an earth, or metallic oxide, in this respect. 
The following are given as experimental demonstrations of its 
properties:—An acid solution, put on a plate of zinc, gave a 
yellow spot with metallic splendour. This, well washed, dis- 
solved in an acid, and tested by triple prussiate of potassa, gave 
a blue-white precipitate ; the blue colour being attributed to the 
new substance. ‘The solution that had acted on the zine gave 
no blue colour with the test, but only a white. : 
A portion of it mixed with lamp-black and oil, and heated 
violently in a crucible for half an hour, left a reddish crust, the 
solution of which, in acids, gave an azure precipitate with the tri- 
ple prussiate. 
The azure matter burned in the fire with facility, and left a re- 
siduum of a bright red colour, if the heat had been intense 5 but 
if moderate and continued, the residuum is scarcely red, and 
when placed in water produces flocculi of the substance and bub- 
bles of the gas. 
Ammonia dissolves the substance, making it first yellow, then 
green; when heated moderately, a residuum is obtained of a 
yellow metallic colour; if more heated it becomes white, and 
does not seem to differ from the substance first dissolved. The 
yellow matter dissolved in dilute acid gives a red tint to ferro- 
prussiate of potassa, which exposed to the air becomes green, 
Other changes take place. 
Nitric acid appears to alter the nature of the new substance. 
When it is added in a concentrated state to the substance, or its 
salts, the prussiate does not then produce a blue precipitate, but 
a yellow tinge. Sulphuric acid, when assisted by heat, offers 
similar phenomena, One 
