_ quantities of gas. 
ei2 Proceedings of Learned ‘Societies. 
this substance with greater energy than 
any other known bodies. Hence thes 
minute theory of oxydation of the basis 
of the alkalies in the air is this:—oxygen 
gas is first attracted by them, and alkali 
formed; this alkali speedily absorbs 
“water; this water is again decomposed ; 
therefore, during the conversion of a glo. 
bule into alkaline solution, 
stant and rapid disengagement of small 
From the facts related, 
of which we mention only a part, it is 
inferred by Mr. Davy, that there 1s the 
same evidence for the decomposition of 
potash and soda into oxygen and two 
peculiar substances, as there is for the 
decompositions of sulphuric and phos- 
phoric acids and the metallic oxydes in- 
to oxygen and their respective bases, In 
the analyses, no substances capable of 
dec: omposition are present, but the alka- 
hes and a minute Aghe of moisture ; 
which'seems in no other way essential to 
the result, than in rendering thena con- 
ductors at the surface: for he has ascer- 
tained that the new substances are not 
generated till the interior, which 1s dry, 
begins to be fused. 
The combustible bases of the fixed al- 
kalies, seem to be repelled as other com= 
bustible substances, by positively electri- 
fied surfaces, and aitracted by negative- 
Jy* electrified surfaces, and the oxygen 
follows the contrary order: or, the oxygen 
being naturally possessed of the negative 
energy, and the bases of the positive, do 
not remam in combination when either 
of them is brought into an electrical state 
opposite to its natural one. 
After Mr. Davy detected the bases of 
the fixed atkalies, he found great dilfical- 
ty in preserving and confining them so as 
to examine ‘their ‘properties; bat he 
found that in recently distilled naptha 
they might be preserved some days with- 
cut mach change. The basis of potash 
at 60° of Fahrenheit possessed the general 
appearance of amercury, so as not to be 
distinguished from it, but at that degree 
ef temperature, it is only imperfectly 
fluid ; .at 70° it is more fluid, and at 
100° its fluidity is perfect, so that diffe- 
rent globules will run ito one, At 50° 
it is soft and malleable, with the lustre of 
polished silver, and at the freezing point 
it becomes harder and brittle, and when 
broken into fragments, exhibits a crys- 
tallized texture, which by ,means of the 
microscope seems composed of beautiful 
facets of.a perfect whiteness, and: gh 
metallic splendor. Ata. heat approach- 
ing reduess, it is converted inte vapour, 
there 1s avcon- 
conductor of heat; 
[April ify 
and is found unaltered after distillation. 
—It is a perfect conductor of electricity. 
When a‘spark is taken from the Voltaic 
battery from a large globule; the light 
ds green, and combustion takes place’ at 
the point of contact only. When a 
small globule is used, it is completely 
dissipated with explosion accompanied 
by a most vivid flame. Itis an excellent 
but resembling the 
metals in all these sensible properties, it. 
as very different from any of them in spe- 
CHIC gravity, heing only as 6 to 10, coms 
pared with water, so that it is the lightest 
fluid body know o 
With respect. to themeal relations ; 
it combines with oxygen, slowly and withs 
ut flame, at all teinperatures below that 
of vaporization ; ; but at tlis temperature 
combustion faies place, and the heht ' 
is of a brillant whiteness, and the heat 
intense. When a globule is heated in | 
hydrogen gas at a d@gree below its point - 
of vaporization, it seems to dissolve in it, 
for the globule diminishes ingolume, and 
the gas explodes with alkalme fumes 
and bright ligbt when suffered to pass in- 
to the air. When brought into contact 
with water, it decomposes it with great 
violence; an instantaneous explosion is 
preduced with bright fame, and a solution 
of pure potash is the result. When a’ 
globule of this substance is placed upon 
ice, it instantly burns with a bright flame, 
and a deep hole is made in the ice, 
which is found to contain a salatiom of 
potash. 
Theory,:—The phenomena seem to de- 
pend on the strong attraction of the po- 
tassium for oxygen ; and of the potash for 
water. The heat which arises from two 
causes, decomposition and combinatian, 
is sufficiently intense to produce inflame 
mation. Lhe production of. alkali m 
the decomposition of water by potassium, 
is shewn by dropping a globule of it upon 
moistened paper, tinged with turmeric. 
Atthe moment that the globule comes 
into contact with the water, it burns, 
and moves rapidly upon the paper, as if 
in search of moisture, leaving behind it 
a deep reddish brown trace, and acting 
upon the paper as dry caustic, potash, 
So strong is the attraction. of. potash for 
oxygen, and so great the ebergy of its ace 
tion upon ‘water, that.it discovers, and 
decomposes the small quantities of water 
contained im alcohol and éther.’ Potash 
is insoluble in ether; but when potassium, 
the basis, is thrown into jt, oxygen is furs 
nished, and hydrogen BAS. is, _ disengaged, 
and the alkali as it forms renders the. 
ether 
