Volcanic and Metalliferous Eruptions. 95 
4. Simple bodies which enter into the composition of the 
basic rocks, or those whose mode of eruption has differed from 
that of volcanic rocks, especially in the rarity of scoriz ; such 
are the serpentines, traps, &c. 
5. Simple bodies, composing granitic or acidiferous rocks ; 
that is to say, rocks in which the bases are saturated with 
silica, and in which the silica is in excess; such are quartz- 
iferous porphyry, diorite, syenite, protogine, granite, pegma- 
tite. 
6. Simple bodies, which enter into the composition of stan- 
niferous veins, or veins of substances which accompany tin. 
7. Simple bodies of ordinary or plumbiferous veins and 
others, to which have been added the bodies which enter into 
the composition of the crystallised masses contained in the 
geodes of amygdaloids, in the fissures of septaria, &c. 
8. The elements met with in mineral waters. Itis to be re- 
marked that this list is, so to speak, only an extract of the 
list of bodies which are found in ordinary veins. 
9. Simple bodies found in the emanations of existing vol- 
canoes. This is a synopsis of such as are found in mineral 
springs ; yet cobalt, lead, and selenium, which are found here 
in very inconsiderable quantities, are wanting in the list of 
simple bodies occurring in mineral waters. By comparing 
columns 2 and 9, with columns 5 and 6, we infer that the 
foci of active volcanoes are the poorest in simple bodies of 
those which have acted at the earth’s surface. A great part 
of the simple bodies have been set apart in the first geological 
phenomena, so that they do not reappear elsewhere; there 
was among simple bodies a gradual selection, constituting a 
great phenomenon, which was going on during the whole time 
the earth’s crust was forming, but the effects of it have varied 
in proportion as the earth’s crust became thicker. 
10. Simple bodies found in a native state on the surface of 
the globe. Some of them (palladium, rhodium, ruthenium, 
iridium, platina),do not form lasting combinations but among 
themselves ; they appear to constitute a department by them- 
selves in the midst of the mineralogical world. 
11. Bodies found in erolites, to the number of twenty-one. 
