196 
THE GEOLOGIST. 
manifest to ns the internal activity of our globe, immense bodies of 
water, in the form of vapour, are disengaged. 
" One naturally asks if the supply of this water is not kept up 
partially, at least, from the surface, and, if so, by what means ? 
" It is difficult to imagine this supply produced by a free circula- 
tion ; for the way open to the descending water would form a means 
of escape which would naturally offer itself to the ascending vapour. 
ISTow the immense pressure of this vapour in the volcanic districts — 
a pressure gi'eat enough to force columns of lava, about three times 
denser than water, to vast heights above the sea -level — proves that 
these safety-valves do not exist. 
" I have therefore been led to examine whether the water cannot 
penetrate into these deep and hot reservoirs, not by fissures as pre- 
viously imagined, but in virtue of the porosity and capillarity of the 
intervening beds." 
M. Daubree then refers to the experiments carried on by M. Jamin, 
showing the influence of capillary attraction in changing the condi- 
tions of equilibrium between different pressures by means of a column 
of liquid, and points out that the geological problem requii^es a 
variation in the temperature not introduced by M. Jamin, — in fact 
the liquid in one part of the connecting column must be reduced to a 
state of .vapour, in which, perhaps, it will be governed by different 
laws. 
M. Daubree then proceeds to describe his ajoparatus as follows : — 
" I have therefore constructed an arrangement, of which the prin- 
cipal end is to join — by means of a partition of porous sandstone of a 
fine close grain — on one side a closed chamber, in which the pressure 
of the steam=one seven-eighth atmospheres, and on the other a space 
in direct communication with the external aii', half filled with water, 
which soon was heated to the boiling point : in the latter chamber — 
of course, being open to the atmosphere — the ordinary pressure was 
not exceeded, although the thickness of the sandstone partition was 
but two centimetres. The result of the experiment proves that the 
water is not driven back by the counter-pressure of the vapour : the 
difference of the pressure on both sides of the partition does not 
prevent the liquid from penetrating from the region comparatively 
cold to the region comparatively hot, by a kind of capillary attraction ; 
favoured also by the rapid evaporation going on in the latter." 
M. Daubree promises further experiments with a thicker partition, 
which will enable the vapour in the fii^st chamber to be raised to a 
higher temperature. 
The results he has already arrived at prove that capillary attraction, 
in addition to weight, can — in spite of very strong interior counter- 
pressure — force water to penetrate from the superficial and cold 
regions of the globe into the interior, where, by reason of high the 
temperature and pressure, it, in the shape of steam, is capable of 
producing gi^eat mechanical and chemical results. 
" Do not the foregoing experiments," asks M. Daubree, " also make 
us acquainted with the main-spring of volcanic action and of other 
