14 ATOMS. 



liquid. If the liquid sulphur be exposed to a still higher 



temperature, it passes off in the form of a vapor or gas. 



11. CONTACT OF ATOMS. The atoms 



Are atoms in o f ma tter are not supposed to be in ab- 



contact ? 



What is the solute contact in either solids, liquids, 



of or g aseS " This is l nferred fr m the fact 



cohesion in bo- that all substances may be diminished in 

 bulk by pressure. But in solid bodies the 

 attraction of cohesion between the atoms is strongest, 

 and they are more nearly and firmly bound together. 

 In liquids, cohesion is less than in solids, and the atoms 

 are farther separated. In gases, cohesion is entirely 

 overcome, and but for gravity, the atoms would sepa- 

 rate themselves indefinitely. 



Heat is the main cause of this difference in cohesion. 

 This subject will be more fully considered in the chap- 

 ter on Heat or Caloric.* 



* The subject of crystalization belongs to Physics, and in a strictly 

 scientific arrangement, would be considered at this point. The student 

 will find the most accessible illustrations of the subject in the Salts, 

 which are considered later in the work, and it has therefore been in- 

 troduced in the chapter which treats of these compounds. It is to be 

 borne in mind that what is there stated, relates to other compounds 

 and to elementary substances, as well as to salts. 



