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Chemical  Nomenclature. 
(  Am.  Jour.  Phaejt^ 
1     Nov.  1, 1872. 
CHEMICAL  NOMENCLATURE  * 
By  Professor  A.  Crum  Brown. 
Setting  aside  in  the  meantime  "trivial"  or  " proper  names'7 
(names  which  are  simply  arbitrary  words  or  marks,  each  indicating, 
in  virtue  of  a  convention  applicable  to  each  individual  case,  a  par- 
ticular substance),  there  are  two  systems  or  kinds  of  systems  of 
chemical  nomenclature.  These  may  be  distinguished  as,  1st,  the  com- 
position system,  and  2d,  the  functional  or  relational  system,  or  class 
of  systems.  In  the  first  the  name  of  a  compound  indicates  the  ele- 
ments or  radicals  contained  in  it,  and  sometimes  their  proportions. 
Thus  Chlornatrium,  Chloriod,  dreifach  Chloriod,  Siliciumwasserstoff, 
etc.  In  English  we  have  few  names  so  distinctly  compositional  in 
form  (we  have,  indeed,  zinc  methyl  and  all  the  other  allied  names), 
but  many  of  our  names,  although  functional  in  form,  are  really  com- 
positional. Thus,  chloride  of  A  means  with  us  nothing  more  than, 
or  different  from,  a  compound  containing  the  elements  chlorine  and 
A ;  and  chloride  of  sodium,  chloride  of  iodine,  ter-chloride  of  iodine,, 
siliciureted  hydrogen  not  only  represent  the  same  substances  as  the 
German  names  just  quoted,  but  tell  us  neither  more  nor  less  about  the 
substances  than  these  German  names  do.  On  the  other  hand,  func- 
tional names  indicate  the  chemical  relations  between  substances.  We 
may  take  as  examples  such  names  as  the  anhydride,  the  amide,  the 
aldehyde,  the  nitrile  of  acetic  acid.  These  derivatives  of  acetic  acid 
contain  no  acetic  ttcid,  but  they  stand  in  certain  definite  relations  to 
that  substance,  and  the  anhydrides,  amides,  aldehydes,  and  nitriles  of 
other  acids  stand  in  the  same  relation  to  them.  What  is  still,  not- 
withstanding the  efforts  of  modern  chemists,  the  common  popular 
nomenclature  of  salts,  although  originally  intended  as  a  compositional 
nomenclature,  might  with  perfect  consistency,  be  retained  as  a  func- 
tional nomenclature.  The  objection  to  the  term  " muriate  of  soda" 
was  that  the  substance  so  named  contains  no  soda.  But  the  amide  of 
benzoic  acid  contains  no  benzoic  acid.  Soda  contains  oxygen ;  mu- 
riate of  soda  contains  none  (unless  chlorine  be  an  oxide),  but  the 
nitrile  of  benzoic  acid  contains  no  oxygen,  although  the  acid  itself 
does.  The  name  muriate  of  soda  originally  meant  the  compound  of 
anhydrous  muriatic  acid,  2HC1 — H20,  and  anhydrous  soda  Na20, 
(2HC1 — H20)  +  Na20.    We  may  now,  if  we  please,  use  the  name  to 
*  Paper  read  before  the  Chemical  Section  of  the  British  Association  at 
Brighton. 
