The Two Electricities. 373 
Over this mixture he introduced two ounces of iron turn- 
ings. From these ingredients he obtained two and a half 
gros of potassium, in the form of brilliant buttons swim- 
ming in the Naphtha. 
In the ee experiment, ciate ounces of siibCaeonate, 
of potash, mixed with six ounces of iron turnings and two 
ounces of charcoal, and these covered with one ounce of 
iron turnings, yielded two gros and ey grains of po- 
tassium. 
In the third experiment six ounces of subcarbonate of pot- 
ash were heated with three ounces of charcoal, without 
any iron, and three gros of potassium were obtained. 
In the fourth experiment, to obviate the inference that 
the iron of the apparatus might have effected the reduc- 
tion, he heated the same mixture in an earthen retort. 
The same indications of the formation of potassium were 
manifested, by the production of inflammable gasses, &c., 
but at the moment when the potassium was expected, the 
retort broke. On putting the neck of it, when cold, into 
water, inflammation ensued, proving that the metal had 
been produced. 
Upon trying the experiment a iron alone, without 
eharcoal, not an atom of potassium was obtained, though 
the process was kept up for two hours, and the fire raised 
as high as it could be, with such an apparatus. 
It appears, therefore, that with a common air furnace, 
auch as are used for melting small quantities of metal, 
and with an iron bottle and gun barrel, potassium may be 
obtained by the agency of charcoal, and at a heat which 
does not endanger the safety of the apparatus. In this me- 
thod also the subcarbonates answer the purpose better 
than the caustic alkalies. 
Bib. Univ. Jan. 1823. 
5. The two electricities may be distinguished from each 
other by turning the electric current, as it issues froma 
point, upon the tongue. The taste of the positive current 
is acid, and that of the negative current is more caustic 
and alkaline. 
Manuel de Chimie par Berzelius. 
