Prof. Necker on the History and Progress of Geology. 299 
lects facts, and arranges them, according to their natural rela- 
tions, and not according to fallacious analogies or theories, esta- 
blished a priori. 
To labour to describe geologically in detail, and Strictly ac- 
cording to nature, the country which he is called to examine ; 
to make use of all the aids afforded, by a more perfect know- 
ledge of mineralogy, and of the study of fossil organic bodies ; 
to employ sketches and topographical charts, to represent, with 
fidelity, the geological constitution of each district, the form, 
position, and alternation of strata, their accidents and veins ; to 
connect thus the localities already examined, by the investiga- 
tion of the intermediate places ; — such are the objects which, at 
the present day, the geologist should have in view. The 
science requires detailed facts to establish accurate comparisons 
between the various points of the globe, and avoid those hasty 
analogies to which the propensity to a seductive, but dangerous 
display of erudition, sometimes induces us to deliver ourselves, 
and which produce only confusion in the science. 
But, of what use, it may be asked, are those investigations of 
sterile tracts, arid rocks, stones without value, and worthless pe- 
trifactions ? What advantage can be derived to society, from 
the knowledge of the age, and nature of these volcanic rocks, if 
it cannot prevent the Torre del greco from being traversed by 
lavas, and the plains of Naples and Sicily from being over- 
whelmed by heaps of cinders ? 
I venture to hope, that such a question will never be proposed 
at Geneva, in a city where science has always been honoured 
and cherished. If it were, however, necessary to shew, that 
geology has as often contributed to the amelioration of the con- 
dition of individuals as to the advantage of states, I would in- 
vite you to cast a glance upon the magnificent work of M. He- 
ron de Villefosse, to see what the working of mines, of all sorts, 
has gained, by the improvement of geognosy. I might point 
out services rendered to agriculture and geography, by the ad- 
vancement of our knowledge in physical geography. Lastly, I 
might cite the salt-springs given to Western Germany, the in- 
exhaustible salt-mine of Vic to France, solely through well ap- 
plied geological calculations, as well as the mines of lithoid car- 
bonate of iron, of so much importance in England, discovered 
