On the Water which permeates through Strata. 173 
II. On the Water which permeates through Strata, considered as a 
Dynamic Power, By Andrew Taylor, Esq. 
The writer is unaware that physical geologists have rightly 
appreciated the fact that vast bodies of water are held in 
great masses of the strata of various formations, under con- 
ditions admitting of the operation of two well-known hy- 
draulic laws. It is proposed merely to call attention to this 
power in geological dynamics without entering into any de- 
tailed consideration of its extent and limits. 
The first of the hydraulic laws referred to is thus ex- 
pressed by Dr Arnott in the new edition of his " Elements 
of Physics — " In a quantity of fluid submitted to com- 
pression the whole mass is equally affected, and similarly in 
all directions. A given pressure, therefore, made upon an 
inch of the surface of a fluid confined in a vessel as by a plug 
forced inwards, is suddenly borne by every inch of the in- 
ternal surface of the vessel, however large, and by every 
inch of the surface of any body immersed in the fluid." 
This law is well known from the numerous popular illustra- 
tions of which it is capable, such as the Bramah Press and 
the bursting of a water barrel from the pressure of water 
admitted into it by a long tube of very small bore. It is the 
most advantageous way known of employing a small force 
to counteract a very great one. Thus, through the medium 
of a confined fluid, a force of one pound, acting upon an 
inch square of the fluid surface in a vessel, may become a 
bursting force of ten, or a hundred, or a thousand pounds, 
according to the size of the vessel, or may be used as a 
mechanical power to overcome a force much more intense 
than itself." Taking this law in conjunction with another 
about to be mentioned. Sir William Armstrong has given 
the world that powerful mechanical invention the " Accu- 
mulator," by which the heaviest loads, such as draw-bridges 
with heavy railway trains, may be lifted with the most per- 
fect ease. This second law is thus expressed by Dr Arnott : 
In any fluid, the particles that are below bear the weight 
of those that are above, and there is therefore a pressure 
among them, increasing in exact proportion to the perpen- 
