158 Reviews—Journal of Royal Microscopical Society. 
the texture of clay extruded under powerful pressure through an 
orifice, geologists will scarcely think this a representation of the 
common process in Nature. He remarks that in this case lamination 
is produced in the direction of the pressure, instead of at right-angles 
to it, as in the experiments of Sorby and Tyndall. But in truth 
their experiments produced the structure by pressure : these gene- 
rate it only by flow. He remarks that a very small molecular 
motion is sufficient to develope the structure, but this does not seem 
obvious. The result which appears most interesting is that extreme 
pressure can produce in many apparent solids a kind of flow; so 
that there may be difficulty in distinguishing between the flow of a 
slightly viscous solid under powerful constraint, and the free motion 
of a body fluid from heat. 
The discussion of the fan-structure in the Central Alpine gneiss 
is somewhat difficult to understand. In his experiments M. Daubrée 
seems to imply that the bedding was already vertical when forma- 
tion of the fan-structure commenced. Yet it is not quite clear 
whether he does not consider the gneiss to have been extruded 
through rents in the superincumbent strata, as the clay in his experi- 
ment was extruded from the orifice in the press. 
The last chapter gives the results of some experiments on the heat 
developed by crushing, grinding, and mashing clay, and in the 
mutual friction of rocks. As in the first section of the work it was 
argued that comparatively moderate heat might produce extensive 
metamorphism, so here the object is to show that such movements of 
strata as have been described could easily generate a heat which 
would be sufficient. 
The second volume, which has just appeared, M. Daubrée devotes 
to “Cosmology,” discussed mainly by aid of the phenomena of 
meteorites. KK. H. (Cambridge). 
IIJ.—Tue Journat oF THE Royat Mrcroscorican Socrery. Vol. 
II. Nos. 4-7, and Supplemental No. 7a. For June to December, 
1879. 8vo. (London and Edinburgh : Williams and Norgate.) 
INCE our last notice (October, 1879) of this valuable periodical, 
the energetic Editor, Frank Crisp, with the assistance of other 
able Fellows of the Society, T. Jeffery Parker, A. W. Bennett, 
and F. Jeffrey Bell, has successfully carried out the improved plan 
of the Journal, and given to the scientific world a vast amount of 
original and derived information on the many subjects interesting to 
Microscopists, and therefore to Naturalists of many denominations. 
The contents of more than 300 serial publications, from all civilized 
countries, are laid before the readers of the Journal im a classified 
form every two months. On modern applications of the microscope 
to Geology there is a memoir by Fouqué in the “ Revue des Deux 
Mondes,” xxxiv., which is briefly noticed in the “ Journal R. Microse. 
Soc.,” No. 12, p. 778 ; and at p. 459 the blackness of some weathered 
limestone and other rocks is referred to a Protococcus and Lichen. 
