HYDROMECHANICS. 



PART I. 



HYDROSTATICS. 



CHAPTER I. 



EQUILIBRIUM AND PRESSURE OF FLUIDS. 



1. Definitions. Hydromechanics is the science wliich 

 treats of the equilibrium and motion of fluids. It is accord- 

 ingly divided into two parts, Hydrostatics and HydroTcinetics. 



Hydrostatics treats of the equilibrium of fluids. 

 Hydrokinetics treats of the motion of fluids. 



The object of the science of Hydrostatics is to determine 

 the equilibrium and pressure of fluids, the nature of the 

 action which fluids exert upon one another and upon bodies 

 with which they are in contact, and the weight and pressure 

 of solids immersed in them, and to explain and classify, 

 under general laws, the different phenomena to which they 

 give rise. 



2. Three States of Matter. Bodies exist in three 

 different states, depending upon the manner in which their 

 particles are held together. They are either solid or fluid ; 

 and the latter are either liquid or gaseous. 



Solid bodies are those whose particles are held together so 

 firmly that a certain force is necessary to change their forms 



