222 
ON MUHIAT IC ACID. 
had determined the explosion, which is hardly probable, they 
would have been manifested at the commencement of the com- 
bustion ; but not so, when the explosion happened, the principal 
part of the potassium had been converted into potash, and only 
towards the close of the experiment did the explosion occur. — 
On the other side, it is known with what energy potassium de- 
composes water, of which the hydrogen at an elevated temper- 
ature resulting from chemical combination inflames by contact 
with the atmospheric oxygen. Can we not suppose, that the 
capricious influence of the electric forces under peculiar circum- 
stances may bring about the moment when the double combus- 
tion of the potassium and the nascent hydrogen can no longer 
operate in a normal manner and hence cause an explosion ? — 
However, it will be seen from this, that in experimenting with 
potassium, whether in acting upon substances having for their 
constituents the elements of water, or burning it upon this 
liquid, it is always prudent to avoid the dangers of an explo- 
sion. — Journ. de Chim. Med. 
ART. LXIIL— ON A NEW KIND OF ADULTERATION OF THE 
MURIATIC ACID OF COMMERCE. 
By Dr. A. Vogel, Jun. 
The contaminations of muriatic acid hitherto known, 
mostly originating from the sulphuric acid employed in the 
decomposition of common salt, consist for the greatest part 
of sulphurous, sulphuric, and nitric acids, chlorine, the chlo- 
rides of arsenic, tin, iron, and probably of selenium also, if 
the acid of Nordhausen be made use of in the decomposition. 
I lately received an acid of commerce, which, besides traces 
of chlorine and iron, contained none of the above impurities; 
