326 M. Fischer's Memoir of ike Life of Klaproth. 
actually discovered a considerable quantity of fixed alkali in 
felspar, porphyry-slate, and many other minerals. 
By the union of these two effective methods of analysis, 
Klaproth has in fact brought the art of chemical analysis to 
such a degree of perfection, that we are entitled to expect not 
only that all the fundamental constituents of minerals, but even 
their relative qualities, will, by degrees, be determined with per- 
fect correctness. But he not only laid the foundation of this 
reform ; he has even reared a great and considerable portion of 
the superstructure. His analyses have hitherto been found so 
correct, that even in the most careful repetitions of them, whether 
with or without any change of the method of resolution, only 
inconsiderable variations have been found. And, although, as 
has been done lately by some celebrated natural historians, 
great improvements have been suggested merely upon hypo- 
thetical views, yet we are bound to demand that the mistakes 
should first be pointed out by experimental investigators. 
Facts are the only sure foundation not only of chemistry, 
but of all science without exception. Even mathematics and 
philosophy are no exceptions to this ; for they must rest on the 
facts of natural consciousness, if they are at all well founded. 
Hypothetical views are indispensable for the promotion of truth : 
but it is clear that they can never furnish a firm foundation of 
science. Wherever, therefore, there is an evident opposition 
between a hypothesis and facts, our first duty is to examine 
whether the foundation can be so cleared out as to evince either 
the incorrectness of the supposed facts or of the hypothesis. 
But if the foundation cannot be so cleared out, the suspicion of 
incorrectness must then fall upon the hypothesis, until some 
mistake as to facts has been proved. 
It is hence not to be doubted, that even distant posterity will 
honour the merits of this distinguished man, who has not 
merely examined and explained a greater number of facts than 
perhaps any other chemist, but who, more especially by the 
methods of analyses proposed by him, as well as by his own 
excellent models of proceeding, has shewed naturalists the way 
by which they may enrich science with new facts, and may 
render those that are already known still more perfect and 
exact. 
