9 
amongst ns whose pursuits, bearing on the practical purposes of 
life, render a knowledge of mineralogy an element of success. 
The geologist, the engineer, and the architect must have recourse 
to mineralogy to gain acquaintance with many of the materials 
which they employ ; nor, even if they possessed unlimited time 
and means for the acquisition of chemical analyses, could they 
afford to overlook the physical properties which are often chiefly 
instrumental in fitting those substances to their several appli- 
cations. The agriculturist, if he wish to modify and improve 
the condition of his soils, must become familiar with the appear- 
ance and qualities of the marls, limestone, gypsum, phosphorite, 
and other minerals, which are now beginning to exert a remark- 
able influence on his art. The antiquary, without a knowledge 
of the stones from which the ancient inhabitants of the earth 
sculptured their idols, reared their temples, or fashioned their 
rude implements, and of the ores from which they produced 
their metals and alloys, can draw no sound conclusions as to the 
comparative civilisation of distant epochs, nor guard himself 
from the blunders consequent on faulty observation or crude 
description. Who, again, that is not insensible to the varied 
beauties of the brilliant gem, would hesitate to prefer to deter- 
mine its nature by the methods of mineralogy instead of entrust- 
ing it to the chemist, who, with ruthless hand and devouring 
acids, must destroy its substance ere he can pronounce upon its 
character ? 
Other and numerous mineral productions there are for a 
decision on whose value we are dependent on the aid of analysis. 
Among the irregularly mingled bodies to which 1 have before 
alluded are many which, like the iron ores lately discovered in 
the oolitic formation, can only be determined as to their impor- 
tance by accurate assay. Few among the crowds who at the 
late Industrial Exhibition swept by the series of iron ores 
brought together from all parts of Britain by Mr. Blackwell, 
could have prophesied that the collection of half a dozen of those 
sombre stones would give rise within a few months to an activo 
industry, which bids fair to develope a new phase in the gigantic 
phenomenon of the British iron trade. An example, this, of 
the mutual dependence and assistance of three sister sciences, 
where geological reasoning had to point out the tract in which 
