Lawrence Scientific School. 357 
uble double salts with fluorid of potassium, the fluorid of gluci- 
num behaves like a bifluorid, so as to suggest that glucina may: 
possibly be GO, instead of GO orG,O,. Ammonia precipitates 
glucina directly from the solution of the double fluorid. When 
a solution of fluorid of sodium is added to one of aluminum and 
—- the whole of the aluminum is thrown down in the 
rm of cryolite, Al, F,,3NaF, while the glucinum remains in 
solution. It is probable that this method will give accurate 
quantitative results. 
Hyponiobie acid.—I am indebted to the kindness of Prof. B. 
Silliman, Jr., for a liberal supply of columbite from Middletown, 
Connecticut. Mr. F. W. Tustin has found that the finely pul- 
yerized mineral treated with a solution of three times its weight 
the mere process of 
cee thus obtained by fusion in a platinum crucible gives a 
ass has then a greenish tint. It must be rubbed to ver, 
fine powder before boiling with water acidulated with fluohydrie 
acid. After passing sulphydric acid gas through the solution and 
filtering, the hypo-fluoniobate crystallizes in colorless acicular 
crystals which must be purified by repeated crystallization, The 
salt is much more soluble in hot than in cold water. In this 
Process a considerable quantity of fluosilicate of potassium, fluo- 
tid of calcium, quartz, and other impurities, usually remain upon 
the filter, with the sulphids of tin and tungsten. The difficulty 
in this process consists in separating the iron, when, as in the 
mineral columbite, this is present in comparatively large quan- 
In this case very large platinum or silver vessels and nu- 
merous recrystallizations become necessary. It is better, there- 
Im preparing large quantities of pure hyponiobic acid to 
fuse with fluohydrate of potassium, dissolve the fused mass in 
Water as before, and filter to separate quartz, fluosilicate of po- 
tassium and fluorid of calcium, evaporate the solution to dryness 
and heat with pure sulphuric acid until the whole of the fluorine 
