INFRA-ASTRONOMY 5 1 



the elements become alternately electro-positive 

 (liable to lose one or more electrons) and electro- 

 negative (able to take up an additional electron). 

 The former are more numerous than the latter. 



Both kinds of atoms are, of course, liable to both 

 loss and gain of electrons. Thus chlorine, which 

 gams an electron easily, is just as well able to form 

 molecules as hydrogen, which loses them easily. 

 But when chlorine molecules and hydrogen mole- 

 cules meet, the positive hydrogen atom quickly joins 

 the negative chlorine atom, while the negative 

 hydrogen atom as quickly passes its superfluous 

 electron over to the positive chlorine atom, and then 

 loses another electron to it. The union between the 

 two hydrogen and the two chlorine atoms is thus 

 dissolved, and two molecules of hydrochloric acid 

 are formed instead of the original molecules. This 

 change, which liberates a considerable potential 

 energy, gives rise to a great speed of translation 

 or rotation of the combining bodies, which to us 

 appears as heat. 



To give a more graphic picture of these occurrences 



than can be obtained by a technical description, we 



miiy put them into the form of a chronicle of an 



.i- world observatory situated, say, on an electron 



whiqji we will call Talav, 1 revolving round a hydrogen 



:i named Grean, 1 contained in a gas containing 



_rcn and chlorine atoms. Talav is an 



1 These names are the Irish equivalents of " earth " and " sun." 



