392 Royal Institution. 
longitudinal or horizontal, so that that the peristaltic mo- 
tion may not obstruct the natural progress of adhesion. If 
the inucous membrane likewise be functured, inflammation 
and not adhesion takes place. 
. ROYAL INSTITUTION. 
Mr. Davy’s Lectures on Geology.—No. I. 
Mr. Davy, after some introductory observations, pointed 
out two distinct arrangements of rocks—one, characterized 
by a crystalline texture, by a stratification approaching to 
the perpendicular in its direction, and by a total want of 
organic remains; the other, known by the horizontal posi- 
"tion of its strata, and by the intermixture of petrifactions 
and water-worn stones. The first arrangement constitutes 
the primary class of rocks, and the last thesecondary. Both 
are traversed by veins, which were formerly empty fissures, 
but are now filled up, and become, the repositories of me- 
tallic ores.” As the same rocks, in all paris of ihe globe, 
are similarly associated, and..contain similar metallic de- 
posits, their relations and transitions form the most 1mpor-- 
tant part of geology, 
__ Mr. Davy showed the excellence of the present order of 
things, and that the irregularities of the surface of the earth 
were wise contrivances. He pointed out the changes to 
which rocks are at present liable from the action of the air, 
sun, and the vicissitudes of the seasons, and noticed. the 
operations counteracting this destructive process, such as 
the formation of islands at the mouths of rivers, vast pro- 
ductions of coral, and islands the result of submarine fires 3 
and he showed that the degradation of the solid rock itself 
had beneficial consequences—that it gave rise to new soils, 
to the fertilization of barren tracts, to the filling up. of 
Jakes, &c, 
Mr. Davy deferred the examination of the different hy- 
potheses advanced respecting, the past alterations of the 
globe to the concluding part of his course. The two prin- 
cipal hypotheses are the Plutonian and Neptunian. Hooke 
Started the first, in which our continents are supposed to be 
IN a continual state of decay and of renovation, the agencies 
of the elements being the destructive powers, and the ac- 
tion of a great central fire on the detrition of our Jand ac- 
gumulated in the bed of the ocean, the renovating power. 
The central five, its principal engine, has been the object 
of great objection. ial Bee 
Mr. Davy remarked, that the source of this ty 
re 
. 
