OCTOBER 27, 1899. ] 
mere reference to experiments which are not 
described, as, for instance, in the case of deltas. 
The deposition of sediments in the subterrane 
is treated experimentally and chemical altera- 
tions inducing color bands are imitated. 
M. Stanislas Meunier has successfully repro- 
duced fossil footprints by blowing sand upon 
the tracked surface covered with a slight depth 
of water. He conceives, therefore, that fossil 
footprints cannot have been preserved by the 
rise of water spreading sand over the surface 
on which tracks were made. It remains for 
some clever manipulator to prove ;the con- 
verse of this proposition as equally effective. 
The author’s point is a good one, however, and 
the numerous instances in the older strata in 
which mud-tracked surfaces are covered with 
sand is astrong argument in favor of his theory. 
Dessication of strata and their torsion are 
next taken up. The author concludes from his 
experiments that regular rhomboidal jointing is 
not to be explained by torsion as Daubrée 
labored to prove. Neither Daubrée nor the 
author have imitated with any degree of ac- 
curacy the conditions in which the stratum is 
placed when it yields to the jointing strain, and 
critical experiments are much needed in the 
elucidation of an old but not yet satisfactorily 
solved problem. 
A very brief reference to the origin of the 
crystalline rocks deals mainly with the work of 
Messrs. Fouqué and Lévy on the igneous rocks. 
An even shorter discussion of metamorphism 
touches only some of the concomitants of meta- 
morphism, such as the carbonization of wood 
tissue. The experiments of Sénarmont and a 
few others are referred to in the explanation of 
metalliferous veins, and a few words are given 
on the subject of kaolinization and serpentiniza- 
tion. 
Our author now plunges boldly into experi- 
ments designed to elucidate the origin of the 
primitive crust of the globe. He assumes that 
beneath the débris of the surface there exists a 
granitic zone, under which occurs a shell of 
which silica, magnesia and iron constitute the 
greater part, citing, as evidence of this latter 
rock, dunite, and the dolerite with native iron 
at Ovifak. This shell is supposed to have been 
formed by a precipitation from the nebular 
_ SCIENCE, 
611 
gas. The author has obtained in a porcelain: 
tube the synthesis of the principal silicates of 
magnesia without the intervention of fusion in, 
illustration of this conception. He concludes: 
from his experiments that the solid shell of the 
globe which was first formed and which had 
analogies with the solar photosphere, consists. 
of magnesium silicate rocks with an abundance 
of metallic concretions of which the genesis is 
related to the phenomena still evident in the 
material of tin-bearing veins and even in the 
chimneys of voleanoes. There results, he goes 
on to state, a relative distribution, in which the 
consideration of the density of the bodies studied 
at ordinary temperatures plays no part. Me- 
tallic iron, for instance, no ‘‘ longer appears as. 
constituting a massive nucleus, but on the con- 
trary as forming a true shell below which have 
been congealed in later times the rocks of 
which eruptions have procured for us specimens. 
in every geologic epoch.”’ 
In part second of this book over 50 pages are: 
devoted to the application of the experimental 
method tothe problems of deep-seated mechan- 
ical action. The remarks on the effects of 
weight or gravity appear not to be suggested by 
experiments, but to have risen out of the gen- 
eral philosophy of geology. Indented pebbles. 
are ascribed to pure pressure without chemical 
solution. 
An experiment is described with the design: 
of showing the supposed effects of the centrifu- 
gal force upon the original crust of the earth. 
The substances employed in a rotating glass. 
bottle of spherical shape arrange themselves 
about the equator in the inverse order of their 
densities contrary to what would be expected 
from gravity alone. This experiment is largely 
relied upon for some of the conclusions pre- 
viously stated regarding the nucleus of the 
earth. 
An experiment to illustrate the formation of 
volcanic cones reproduces such little burst steam 
bubbles as one sees in the paint-pots of the Yel- 
lowstone Park. Laccoliths are also, it is stated, 
reproducible by means of melted wax injected 
between sheets of plaster having a slight de- 
gree of plasticity. 
Professor Meunier attempts also the famous. 
problem of introducing water into the interior 
