42 



NOMOS. 



before the formation of the molecule of chloride of 

 zinc, with this only difference, that the positive 

 element of the zinc molecule, whose negative ele- 

 ment went to form the molecule of chloride of zinc, 

 is left by itself. The molecule of chloride of zinc 

 takes no part in these changes. Like the hydrogen 

 element of which we have spoken, it escapes out of 

 the circuit, only falling as a precipitate instead of 

 rising as a gas, a fact which we indicate by placing 

 the symbols below the line, with an arrow to indicate 

 the downward tendency. (The molecule of chloride 

 of zinc may be supposed to take no part in the 

 changes of the rest of the circuit, because the 

 affinities of the component elements are too strong to 

 allow the requisite decompositions and recombina- 

 tions.) These changes may be thus represented 

 the first diagram being a repetition of the last. 



ClZn 



I 



Fig. 5. 



Fig. 6. 



These changes being completed, they begin again 



