104 =. D. Dana—Results of the Earth's Contraction. 
Art. XIV.—On some reswits of the Earth's Contraction Jrom cool- 
mg; by James D. Dana. Part IV, Igneous Ejections, Vol- 
canoes, * 
IV. I@neous Esxctions, VoLcaNnosgs. 
sive, and volcanoes: were of increased size and numbers. 
€ questions remaining are— 
lateral pressure? _ 
1. Source of igneous fusion.t—The suggestion of Prof. Hop- 
kins, with regard to the earth’s interior, which has been sus- 
tained on a preceding page,§ offers for the source of igneous 
* For Part I, see vol. vy, p. 423; i bas vi, p. 6; III, vol. vi, p. 13. 
} I say nothing here on the nature or the degree of igneous fusion in plastic 
gene iscussion. 
pressure—at . for an increase of pressure equi 
alent to about five atmospheres,” and adds that then “we should probably have 
the condition under which solidification would commence at the cen i 
tion begun earth w 
ditions discussed, that “the incrustation may have constituted the very first : 
in the solidification, or it may have taken place after the formation of a solid 
