MATTER, LIVING FORCE AND HEAT. 3 



not possess the two qualities bears the name of matter. If 

 we conceive of impenetrability and extension we have the 

 idea of matter, and of matter only. 



" Matter is endowed with an exceedingly great variety 

 of wonderful properties, some of which are common to all 

 matter, while others are present variously, so as to constitute 

 a difference between one body and another. Of the first 

 of these classes, the attraction of gravitation is one of the 

 most important. We observe its presence readily in all 

 solid bodies, the component parts of which are, in the 

 opinion of Majocci, held together by this force. If we break 

 the body in pieces, and remove the separate pieces to a 

 distance from each other, they will still be found to attract 

 each other, though in a very slight degree, owing to the 

 force being one which diminishes very rapidly as the 

 bodies are removed further from one another. The larger the 

 bodies are the more powerful is the force of attraction sub- 

 sisting between them. Hence, although the force of attrac- 

 tion between small bodies can only be appreciated by the 

 most delicate apparatus except in the case of contact, that 

 which is occasioned by a body of immense magnitude, such 

 as the earth, becomes very considerable. This attraction of 

 bodies towards the earth constitutes what is called their 

 weiglit or gravity \ and is always exactly proportional to the 

 quantity of matter. Hence, if any body be found to weigh 

 2 lb., while another only weighs I lb., the former will 

 contain exactly twice as much matter as the latter ; and 

 this is the case, whatever the bulk of the bodies may be : 

 2 lb. weight of air contains exactly twice the quantity of 

 matter that I lb. of lead does. 



" Matter is sometimes endowed with other kinds of 

 attraction besides the attraction of gravitation ; sometimes 



