contained in the Bavarian Tantalite. 361 
Metallic pelopium can be prepared from the chlorid by treat- 
ment with ammonia, in the same way as the metals from the 
chlorid of tantalium and chlorid of niobium. It has the great- 
est resemblance to tantalium. 
When the ignited acids, which are insoluble in almost all rea- 
gents in the moist way, are fused ina silver crucible with hydrate 
of potash, they are dissolved. The fused mass is soluble in wa- 
ter. Hydrate of soda behaves in a different manner. ‘When the 
ignited acids are melted with it, the fused masses obtained are 
not clear; but an insoluble sediment is formed, which does not 
dissolve in any excess of the alkali. If the fused mass be treated 
with a moderate quantity of water, the excess of soda is removed, 
and a white insoluble mass remains. If, after removing the free 
soda, a large portion of water be poured over the insoluble mass, 
it dissolves, and most completely when niobic acid has been em- 
ployed. 
~ The insolubility of the three acids in excess of soda, while the 
tash compounds are soluble in excess of potash, essentially 
characterizes them. In this they differ from similar acids, espe- 
cially from tungstic acid. When the solutions of the soda salts 
are mixed with concentrated solutions of hydrate of soda, they 
immediately become turbid ; if the mixture be made very slow- 
ly and carefully, all three soda salts may be obtained in crystals, 
which are deposited on the sides of the vessel. But crystals only 
of the niobate of soda can be easily obtained of any size. I suc- 
ceeded in obtaining them half an inch’ and more in size, but in 
general they are much smaller. ‘They are sparingly soluble in 
cold water, more readily soluble in hot; the solution may 
boiled without becoming turbid ; it can be evaporated, and the 
niobate of soda deprived of its water of crystallization without 
being decomposed: 'The salt is only rendered insoluble in water 
by being heated to redness. 
The pelopate, and especially the tantalate of soda, are less sta- 
ble; when their solutions are boiled, an insoluble white precipi- 
tate separates, which is an acid salt of soda. 13 
When the niobate of soda is exposed to a red heat, and a cur 
rent of dry sulphuretted hydrogen passed over it, a dark black 
crystalline mass is obtained, from which water removes hydro- 
sulphated sulphuret of sodium, while crystalline sulphuret of ‘ni- 
iim remains undissolved 
When niobic acid is fused with an excess of carbonate of soda 
Until the fused mass no longer decreases in weight, the amount 
Srcoxp Sznixs, Vol. II, No. 9—May, 1847. 46 : 
