Scientific Intelligence—Chemistry. 183 
nitruret of potassium, heated with iron filings, in an iron crucible. From 
twenty grains of ammonia-nitruret of potassium, and the same quantity 
of iron, he states, that he obtained silicon, which, when fused with car- 
bonate of potash, afforded 1.55 grains of silica. According to this ex- 
periment, therefore, nitrogen consists of silicon and hydrogen, or of these 
substances combined with oxygen. Statements of this description cannot 
be read without astonishment; but all surprise vanishes when we direct 
our attention to the continuation of the investigation. The experimenter 
prepared siliciuret of potassium by heating silica with potassium ; he 
then passed a current of dry muriatic acid gas over it, and obtained a 
mixture of one volume of nitrogen and four volumes of hydrogen. Who- 
ever prepares siliciuret of potassium in this manner, can also produce any 
gas he pleases.— Berzelius’ Jahres-Bericht, 1844. 
13. On the occurrence of Xanthic Oxide in Gwano.—Magnus has 
announced that Unger has discovered in his laboratory, in guano, the 
substance which Marcet has named Xanthic Oxide. This body, so in- 
teresting to physiologists and chemists, has been hitherto met with only 
twice in pathological secretions of the kidneys. The most extensive 
researches regarding it we owe to Liebig and Wohler, occasioned by 
their labours on the nature of uric acid. They have given it the name 
of xanthine; but these chemists possessed only a very minute quantity 
of it, obtained from a stone which previously served, in part, for the 
investigation of Stromeyer. 
Xanthie oxide is obtained from guano, by dissolving the latter in muri- 
atic acid, and precipitating the solution by an alkali. Caustic potass elimi- 
nates, from the precipitate, a small quantity of it, which is not always the 
same in amount. By the aid of a stream of carbonic acid gas, or by 
the addition of sal-ammoniac, we extract the xanthic oxide from its so- 
lution in potass, from which it separates in proportion as the ammonia 
disengages. The pulverulent and yellowish substance obtained, possesses 
all the properties which Liebig and Wohler have attributed to xanthic 
oxide, and differs from it only in being soluble in muriatic acid, as is 
apparent from its mode of preparation. But Unger has found that 
xanthic oxide forms not only with muriatic acid, but also with various 
other acids, crystallized compounds, which are soluble in water, and 
which he will afterwards fully describe. 
It thus appears that guano, a substance in itself already so remarkable, 
and which promises the same happy results for the agriculture of Europe, 
as it seems to have yielded in very ancient times for that of South Ame- 
rica, promises likewise a rich harvest of interesting facts to science. 
The small proportion in which the xanthic oxide is found in guano, 
does not allow us to suppose that this substance is produced by slow 
decomposition. The inequality with which this body is found diffused 
among the guano, renders it very probable that it is a pathological product 
which was voided along with the excrements of birds, unless we consent 
to admit that it is there as the normal ejectment of certain birds. At all 
events, it would be of the greatest interest to become acquainted with these 
species of birds, which probably are still living.* 
* From Poggendorff’s Annalen., 1844, No. 5, p. 158. 
