1862.] 



on Mauve and Magenta, 



473 



exists in the free state, or, to use the chemical phrase, the molecule of 

 hydrogen, consists of two atoms of hydrogen. The first of our type- 

 moulds then, charged as it is with one atom (one volume) of hydrogen, 

 associated with another atom (one volume) of hydrogen, represents the 

 molecule of hydrogen, i , i , 



H S 



In water, as you know, we have two atoms (two volumes) of hydrogen, 

 associated with one atom (one volume) of oxygen.* You are reminded 

 of tins fact by our second type-mould, which represents the molecule of 

 water. 



H 



H 



O 



In ammonia, lastly, you have three atoms (three volumes) of hy- 

 drogen, united with one atom (one volume) of nitrogen, a form of con- 

 struction which is recorded in our third type-mould representing the 

 molecule of ammonia. 



Nothing is easier now than to trace the derivation of other substances 

 from hydrogen, from water, from ammonia. Let me remove from our 

 three type-moulds one atom respectively of hydrogen, oxygen, and 

 nitrogen, and fill the places thus vacated with atoms of chlorine, 

 sulphur, and phosphorus, and I have, without giving you the slightest 

 inconvenience, converted hydrogen into hydrochloric acid, water into 

 sulphuretted, and ammonia into phosphoretted hydrogen. 



H 



H 



H m B B B 



♦ Equivalents used : H=l 

 Vol. III. (No. 36.) 



0-16; S=»32; C'=12; N. 



14; Cl-33'5 ; &c. 

 2 K 



