8 INTRODUCTION TO 



siding spirits ' are every day vanishing, and their authority becoming 

 less 1 . 



Although ' spirit ' is a good deal exploded from having a share in 

 the actions of common matter, yet it is still retained in animal matter ; 

 and, most probably, because the action of animal matter is much more 

 extensive and has two states, — the living and the dead : and, as there 

 is no difference in the visible mechanism between the two states, it 

 was natural to suppose that there was what is called an animating or 

 living spirit. 



But matter can have some of its properties changed by very trifling 

 circumstances. A piece of glass is transparent ; bat, if that piece of 

 glass be split, it will become less so ; split it into three, still less so ; 

 and so on till it becomes the most opaque body that can be : and still the 

 whole is composed of transparent glass : therefore, opacity in a whole 

 does not give the least idea of the transparency of its parts. 



The first and great property of matter is what is called its 'vis 

 inertiae ' or resistance, which produces or is the cause of many of the 

 mechanical effects of matter ; but the effect of this property is increased 

 by another property in matter, viz. solidity. 



Matter is naturally in a solid form, or its parts are united and kept 

 together by a property called the attraction of cohesion. The effect [of 

 this property] increases its resistance, because a greater quantity of 

 matter is brought in to act upon impulse, viz. all that matter that is so 

 connected. 



Resistance of matter is as the power of union by the attraction of 

 cohesion and the quantity of matter so united, making one whole, called 

 a solid body ; but, if divided into small parts which are only in contact, 

 so as to easily move upon one another, as gravel, &c, then the resist- 

 ance is as the quantity that is made to move and the friction of the 

 moving parts upon one another. 



Matter in a solid form admits of every possible shape, the attraction 

 of cohesion of each part being stronger than tbe attraction of the whole 

 to its own centre, and which may be called centripetal attraction, or 

 stronger than the attraction of its parts to the earth. From external 

 shape, joined with sufficient sohdity, arise many properties, when 

 matter is opposed to matter ; which becomes the cause of all the 

 mechanical effects of matter. 



But matter can have its attraction of cohesion destroyed, so that its 

 parts can be made to move upon one another, when it is called a fluid : 

 then it has only the attraction of fluidity. The resistance of the fluidity 



1 The dominant idea of the ' Philosophic Positive ' of Comte. 



