326 OBSERVATIONS ON MURIATIC ACID, 
unites with the real earth, forming the hydrate ;—in other 
words, and according to the strict expression of the fact, the 
hydrogen entering into the composition, and forming the ba- 
rytes ;—a result perfectly analogous to the formation of muri- 
atic acid from oxymuriatic gas by the agency of hydrogen. 
The evidence in support of this doctrine, it is evident, is of 
the same kind as that with regard to the doctrine applied to 
the acids. There is the same superior probability in favour of 
the conclusion, that the elements of water, rather than water 
itself, exist in these compounds, from the consideration, that 
modifications of properties so important, are more likely to 
arise from the agency of these elements, than from any action 
which water can exert. And that water does not exist in them, 
in consequence of the strength of attraction which the real al- 
kali, as it has been considered, exerts towards it, is evident 
from this, that on the same principle ammonia ought to con- 
tain combined water in its insulated form, which is not the 
case. The combination of water, therefore, or rather of its 
principles, in these compounds, depends on relations subsist- 
ing among the ultimate elements, not on an affinity exerted by 
the alkali itself; and this adds confirmation to the conclusion, 
that these elements are in ternary union. 
Their superior alkaline energy, compared with the common 
metallic oxides, may obviously arise from the joint action of 
the hydrogen and oxygen, in the same manner that the acidity 
of the ternary, compared with the binary acils, is increased by 
a similar constitution. Thus the class of alkalis will exhibit 
the same relations as the class of acids. Some are compounds 
of a base with oxygen: such are the greater number of the me- 
tallic oxides, and several, probably, of the earths. Ammonia is 
a compound of a base with hydrogen. Potash, soda, barytes, 
strontites, and, probably, lime, are compounds of bases with 
oxygen 
