3i 8 Mr . Chenevix's Enquiries concerning the Nature 
metals, than any two can be from each other. Within the last 
fifteen or twenty years, several new metals and new earths have 
been made known to the world. The names that support these 
discoveries are respectable, and the experiments decisive. If we 
do not give our assent to them, no single proposition in chemistry 
can for a moment stand. But, whether all these are really 
simple substances, or compounds not yet resolved into their 
elements, is what the authors themselves cannot positively as- 
sert; nor would it in the least diminish the merit of their 
observations, if future experiments should prove them to have 
been mistaken, as to the simplicity of those substances. This 
remark should not be confined to later discoveries ; it may as 
justly be applied to those earths and metals with which we have 
been long acquainted. 
With regard to the metals, we have seen how little dependance 
is to be placed on specific gravities. A contrary anomaly to that 
which operates upon platina and mercury, may take place in 
others ; and they may become as much heavier than the mean, 
as the former become lighter. In this state of union, they may 
for a long time appear homogeneous, even by the test of che- 
mical reagents. One of the properties that renders metallic 
substances so precious is, their easy formation into such instru- 
ments as our necessities require. The fragile metals are but of 
secondary consequence ; and, at most, serve to confer on those 
which are ductile, some quality which adapts them better to 
particular purposes. It often happens that, by being alloyed, 
two ductile metals become fragile ; but we have no instance of 
the contrary effect in any high degree. It is therefore more to 
be supposed that we should look to simplification among the 
fragile metals ; and, even at this early period, it may not be too 
