1809.] 
Proceedings of Learned Societies. 
307 
organisation seems to be rather to com- ofa substance, possessing the whiteness 
bine substances into more: complicated 
and diversified arrangements, than to. re~ 
duce them to simple elements.” 
From the fixed alkalies, the professor 
proceeded to the earths, which are non- 
conductors of electricity. The alkalies 
become conducting substances by fusion: 
the infusible nature of the earths, ren- 
dei rd it impossible to operate upon them 
in this state: the strong affinity of their 
bases for-oxygen would not admit of their 
bodies being acted upon by solution. in 
water; and the only methods that proved 
successful, were these by which they were 
operated upon by electricity in some of 
their combinations, or of combining them 
at the moment of their decomposition by 
electricity, in metallic alloys, so as to ob- 
tain evidences of their nature and proper- 
ties. 
On this plan, Mr. Davy undertook a 
series of experiments on Barytes, Stron- 
tites, and Lime, employing upon them 
the same methods as he had used in the 
decomposition of the fixed alkalies. Gas 
was, In each case, copiously evolved, 
which was inflammable; and the earths, 
where in contact with the negative metal- 
lic wires, became dark-coloured, and ex- 
hibited small points, having a metallic 
Justre, which, when exposed to air, gra- 
drally became white: they became white 
likewise when plunged under water, and 
when examined by a magnifier,.a green- 
ish powder seemed to separate from 
them. 
He then made mixtures of dry pot-ash 
im excess, and dry barytes, lime, stron- 
tites, and magnesia, brought them into 
fusion, and acted upon them in the vol- 
taic circuit, as he had done in obtaining 
the metals of thealkalies. [He hoped, by 
this means, that the potassium, and the 
metals of the earths, might be deoxygen- 
ated at the same time, and enter into 
combination in alloy, Metallic substan- 
ces appeared less fusible than potassium, 
which burnt the instant after they had 
formed, and which, by burning, produced 
@ mixture of pot-ash, and the earth em- 
ployed. He had found, that when a mix- 
ture of pot-ash, and the oxides of mercury, 
tin, or lead, was electrified in the Voltaic 
circuit, the decomposition was very ra- 
pid, and an amalgam or an alloy of potas- 
sium was obtained. le tried the same 
on @ mixture of two parts of barytes, and 
one part of oxide of silver very slightly 
moistened ; when it was electrified by iron 
wires, an effervescence took place at both 
points of contact, and a minute quantity 
come covered with a white crust. 
of silver, formed at the negative point. 
A mixture of barytes and red oxide of 
mercury, in the same proportions, was 
electrified in the same manner. A smail 
mass of solid amalgam adhered to the ne- 
gative wire, | which | evidently contained a 
substance that produced barytes by pleas 
sure to air, with the absorption of oxygen; 
and which occasioned the evolution ef 
hydrogen from waier, leaving pure mer- 
cury, and producing a solution of barytes. 
Mixtures of lime, stroatites, magnesia, 
and red oxide of mercury, treated in the 
same manner, gave similar ainalgamis, 
from which the alkaline earths were re- 
generated by the action of airand water. 
While Mr. Davy was pursuing these 
experiments, he heard that Professor Ber- 
zelius, and Dr. Pontin, of Stockholm, had 
succeeded in decomposing barytes and 
lime, by negatively electrifying mercury 
in contact with them, and thatin this way 
they had obtained amaleams of the me. 
tals of these earths. Mr. Da avy repeated 
the experiments with a battery of 500, and 
obtained the most perfect success. ‘The 
mercury gradually became less fluid, and 
after a few minutes was covered with a 
white film of barytes; and when the anal. 
gam was thrown into water, hydrogen was 
disengaged, the mercury remained free, ~ 
and a solution of barytes was formed. 
The result with lime was precisely analo= 
gous, so also was that with’ strontites; 
with magnesia it was with more difficulty 
obtained. All these amalgams may be 
preserved a considerable period under 
naphtha, but in a length of time they be- 
When 
exposed to air, a very few minutes only 
were required, ‘for the oxygenation of the 
bases of the earths. 
In several cases, Mr. Davy exposed 
the amalgams of the metals of the earths, 
containing only a very sinall quantity of 
mereury, to the air, on a delicate ba- 
lance, and he always found that, during 
the conversion of metal into earth, 
there was a considerable increase of 
weight. He also found that, when the 
metals of the earths were burned in @ 
small quantity of air, they absorbed oxy- 
gen, gained weight, and were in a highly 
caustic or unslaked state; for they pro- 
duced strong heat by the contact of water, 
and did not effervesce during their solu- 
tion in acids. Hence it is inferred, that 
the evidence for the composition of the 
alkaline earths, is of the same kind as that 
for the composition of the common me- 
tallic oxides; and the principles of their 
decomposition 
