136 On definite Proportions. 
tile, like an amalgam of platina. In the air it instantly 
blackens, and becomes covered with a thick crust.” When 
it is saturated, it stiffens after some time into a black porous 
mass, from which some globules of quicksilver may be 
pressed out; the remainder is a combination of the prot- 
oxide of mercury with lime, resembling the brown crust 
which forms on the residuum left ‘after the distillation of 
the amalgam of potassium, and the lime may be dissolved 
out of it by water, without a trace of further oxidation, the 
‘ protoxide only remaining. That in these experiments the 
‘quicksilver should be oxidated together with the calcium 
and potassium, would not have been expected: but this 
‘ circumstance must evidently be attributed to the want of a 
substance with which the newly oxidated basis may enter 
into combination ; and this substance is here, in the ab- 
sence of water, the protoxide of mercury, which on the 
contraiy is not formed when the base is oxidated in water. 
If we distil] the amalgam of calcium in a small apparatus 
filled with hydrogen gas, we obtain after a low red heat a 
~ metal with a silvery lustre, which when cold is very brittle, 
-and contains much quicksilver. This metal does not 
- blacken in the air, but becomes covered with a white crust 
‘of caustic lime, which at Jast retains a globule of quick- 
silver in the middle. If we throw the amalgam into water, 
lime is formed, with an evolution of hydrogen gas free 
from smell. If we drop muriatic acid or sal ammoniac 
“into the water, the evolution of gas is increased, and the 
~ hydrogen assumes a strong disagreeable smell, as when irun 
- or zine is dissolved in muriatic acid. I have observed no 
sinell in hydrogen gas, even when it is evolved with great 
- violence from the distilled amalgam of calcium ; the acid 
must consequentiy cooperate in the production of the 
smell; ‘but how does this happen? To assume, that the 
calcium is dissolved in hydrogen, seems not to be sufficient 
for the explanation, since the smell ought in this case to be 
more perceptible without the addition of the acid. When 
the water is saturated with lime, the evolution of gas is al- 
- most entirely interrupted, until more water is added. 
The experiments for the determination of the quantity of 
oxygen in lime are still less to be depended on than those 
which-I have related with regard to the fixed alkalis, and 
for the same reason, that I have always had only very mi- 
nute quantities of the base to operate upon. 
1.) An amalgam of calcium weighing 58'2 grammes 
Jost in water ‘06 gr. To the solution carbonate of am- 
-monia was added, and a precipitate of :145 grammes . cars 
onate 
