g2 Mr. Davy's Lecture on the Decomposition and Composition 
the philosophical division of the classes of bodies, the analogy 
between the greater number of properties must always be 
the foundation of arrangement. 
On this idea, in naming the bases of potash and soda, it will 
be proper to adopt the termination which, by common con- 
sent, has been applied to other newly discovered metals, and 
which, though originally Latin, is now naturalized in our 
language. 
Potasium and Sodium are the names by which I have 
ventured to call the two new substances : and whatever 
changes of theory, with regard to the composition of bodies, 
may hereafter take place, these terms can scarcely express 
an error ; for they may be considered as implying simply 
the metals produced from potash and soda. I have consulted 
with many of the most eminent scientific persons in this 
country, upon the methods of derivation, and the one I have 
adopted has been the one most generally approved. It 
is perhaps more significant than elegant. But it was not 
possible to found names upon specific properties not common 
to both ; and though a name for the basis of soda might have 
been borrowed from the Greek, yet an analogous one could 
not have been applied to that of potash, for the ancients do not 
-seem to have distinguished between the two alkalies. 
The more caution is necessary in avoiding any theoretical 
expression in the terms, because the new electro-chemical 
phenomena that are daily becoming disclosed, seem distinctly 
to shew that the mature time for a complete generalization of 
chemical facts is yet far distant ; and though, in the explana- 
tions of the various results of experiments that have been 
detailed, the antiphlogistic solution of the phenomena has 
