Mr HOPKINS, ON RESEARCHES IN PHYSICAL GEOLOGY. 



77 



that the following diagram may represent a vertical section of it. For 

 suppose the fluid capable of transmitting the (— ) of a force impressed 



upon it, in a direction perpendicular to that of the impressed force ; then 

 if the pressure be transmitted along a broken line consisting of straight 

 lines at right angles to each other, it is clear that the force transmitted 

 along the first straight portion (supposed horizontal), will be - . p, p 

 being the impressed force and acting vertically. Along the second portion 

 of the broken line the transmitted force will be [— ) . p, and generally 



ni 



along the r'" portion it will be f - j . p. If the different portions of the 



broken line be not at right angles to each other, or instead of being 

 straight be curved, the diminution of the transmitted pressure must 

 still be calculated on the same principle. It is important, however, to 

 observe that the thickness of the injected bed would probably influence 

 this diminution very materially, as may be illustrated by the following 

 figure. If the section of the bed be represented by the space between 



the lines ah and cd, a straight line may be drawn in it from one 



