468 Mr. W. H. Balmain on Athogen and Aithonides. 
crucible is sufficiently cool to admit of being handled, rapidly 
transfer the light coherent powder which will be found in the 
interior, to a perfectly dry well-stoppered bottle. 
Properties.—A white powder, light as prepared magnesia, 
infusible, and fixed at a white heat. Heated before the blow- 
pipe it burns rapidly, giving the flame a green colour, but 
without phosphorescing. Exposed to air for a few seconds 
and then heated in a tube, it yields a palpable quantity of 
ammonia. Heated with hydrate of potass, it yields ammonia 
abundantly. It is not altered by hydrogen at a low red heat, 
nor by chlorine at ordinary temperatures, nor by the vapour 
of iodine; and it is insoluble in water, but communicates to 
it an alkaline reaction. It is decomposed with effervescence 
by nitric and sulphuric acids, and there remains after evapo- 
ration boracic acid. It deflagrates with chlorate of potass and 
with nitre. Heated to redness with potassium and zinc it 
yields zethonides of those metals. 
Zithonide of Potassium. Preparation—Take seven parts of 
finely powdered boracic acid and twenty parts of cyanide of 
potassium, free from water, and, as far as possible, from cya~ 
nate of potass and iron; and having lined a Hessian crucible 
with a paste of powdered charcoal and gum, and heated it 
until all water has passed away, place the mixture in the cru- 
cible, cover it by inverting and luting a smaller crucible over 
it, and heat it to whiteness for an hour: it is advisable to use 
a crucible as a cover, that there may be sufficient room for 
spurious sublimation, and the rent-hole should be bored in 
the bottom of this crucible and not in the luting at the side; 
and further to avoid the penetration of oxygen to the mate- 
rials, it is well to line the upper in like manner with the 
lower ; or, by heating together potassium and zthogen avoid- 
ing an excess of potassium, and heating the result with nitric 
acid to free it from excess of zthogen. 
Properties.—A light white solid, infusible and insoluble 
even when heated in water, in solution of potass, hydrochloric 
acid, sulphuric acid (strong and diluted), nitric acid, and so- 
lution of chlorine; it is not altered upon exposure to air, nor 
does it affect the most delicate turmeric paper when placed 
upon it ina moist state. Heated with hydrate of potass or 
soda, it yields ammonia abundantly. In the deoxidizing flame 
of the blowpipe it is not altered, nor does it communicate any 
colour to the flame: but in the oxidizing flame it gives a 
strong green colour, and gradually fuses, yielding a perfect 
bead which is transparent, hot and cold ; and when placed with 
a drop of water upon test papers, turned turmeric brown and 
red litmus blue. When the outside flame impinges upon a large 
