On the W ater which permeates through Strata. 1 73 



II. On the Water ivhich 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- 



ict 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- 



