94 M. Elie de Beaumont on 
On Volcanic and Metalliferous Eruptions. By M. ELIE DE 
BEAUMONT. (With a Table.) 
Voleanic eruptions bring to the surface of the globe, on 
the one hand, rocks in a state of fusion, lavas, and all their 
accompaniments ; these are volcanic products after the man- 
ner of lavas ; and on the other, substances volatilized or car- 
ried along in their molecular state, such as steam, gas, salts, 
&c.; these are volcanic products after the manner of sulphur. 
On going backwards in the course of geological periods, we 
observe that volcanic substances after the manner of lavas 
become more and more rich in silica ; and that voleanic sub- 
stances after the manner of sulphur become more and more 
varied. The latter are the produce of the humid way, in the 
same manner as the products of thermal springs are those 
of heat. The greater part of metallic veins appear referable 
to this. 
The following is a brief summary which M. E. de Beau- 
mont gives of his memoir. The numbers refer to those in 
the Table at the end of the article. 
1. Bodies most generally spread over the surface of the 
globe. These are sixteen in number.* We may add tita- 
nium, bromium, iodium, selenium, which are generally dif- 
fused in small quantities, which would raise the number of 
these bodies to twenty; but of these not above twelve are 
found frequently and in abundance. 
2. Fourteen simple bodies, which enter into the composi- 
tion of various species of Javas produced by existing volcanoes. 
Although sulphur is found in sulphuric acid, hydrogen in the 
water of haiiyne, chlore in sodalite, fluor in mica, yet these 
four bodies occur in lavas only in an exceptional way, and 
the number ought, therefore, to be reduced to ten. 
3. Fifteen simple bodies, which compose the ancient vol- 
canic rocks. 
* See Researches on the Theoretic Portion of Geology. By Sir Henry de 
la Beche. 
