90 
Sir H. Davy on a new Substance 
. That it produces so little heat and so seldom light in en- 
tering into combination, may be accounted for from its solid 
form’ and its ‘great weight as an 'dement. Potassium, how- 
ever, as I have mentioned, burns in the violet coloured gas, 
and when this gas is thrown upon the flame of hydrogen, it 
seems to support its combustion. 
The saturating or neutralising powers of the new substance 
appear to be greater than those of oxygen, and less than those 
of chlorine. 
It agrees with chlorine and fluorine in forming acids with 
hydrogen, and it agrees with oxygen in forming an acid with 
chlorine. 
In my first -experiments I conceived that it formed ’sub- 
stances analogous to alkalies in combining with the alkaline 
metals, for the compound produced by its action upon solution 
of potassa, even when the substance was in great excess, red- 
dened turmeric paper, and rendered green paper tinged with 
the juice of violets; but I have since found that this is owing 
to a small quantity of subcarbonate of potassa which existed 
in 'the hydrate’ of potassa; and when the compound is treated 
with the acid the substance forms with hydrogen, and heated 
to redness, it loses this property ; and when thus formed, its 
taste more resembles that of a neutral salt than of aivaikali. 
I cannot yet say with certainty W'hether its cornpound with 
potassium has powers like the oxides, of neutralising those 
acids which it does not decompose, as -in all the experiments 
I' have made on this point I used the compound w-hich reddens 
turmeric; this neutralised the phosphorous, sulphurous, and 
boracic’^acids, but the effect may possibly depend upon the 
undecomposed carbonate. 
