ANoVembeS™*}      Review  of  Chemistry  of  the  U.S.P.  509 
Let  us  see  the  number  of  times  the  New  Yorker  gets  a  true  result 
of  analysis.  The  mean  pressure  is  29  854  (29-92  is  760  mm.  or  no 
correction),  plus  one  inch  is  30-854.  So  when  the  barometer  stands 
at  30-854,  vapor  tension  is  compensated,  and  as  you  are  not  above 
250  metres,  you  must  ignore  the  barometer!  Please  take  note  of 
the  fact  that  the  highest  reading  for  New  York  observed  is  30-  60, 
and  that  during  the  entire  year  30-50  occurs  only  twice.  Therefore, 
brother  pharmacists,  you  will  always  have  wrong  results  in  the  assay 
of  spirits  of  nitre ;  your  assays  will  always  be  high,  from  a  per  cent, 
to  8  per  cent.  only.  One  consolation  to  you,  we  are  worse  off  in  St. 
Louis,  even  the  cyclone  blew  us  way  below  any  reading  you  may 
have  in  New  York.  For  further  details  on  this  method  of  analysis, 
see  "  Hinrichs'  General  Chemistry,"  pages  228-231. 
ATOMIC  WEIGHT. 
These  are  probably  the  most  important  data  in  chemistry ;  natur- 
ally they  are  then  subject  of  continual  research.  It  will  be  remem- 
bered that  this  research  gave  us  a  number  of  new  elements  of  the 
argon  variety.  Lord  Raleigh,  in  comparing  the  density  of  chemi- 
cal nitrogen  and  that  supposed  to  be  purest  nitrogen  obtained  from 
the  air,  found  the  latter  to  be  relatively  heavier  than  the  former. 
When  you  consider  the  thoroughness  wherewith  nitrogen  from  air 
has  been  studied  during  the  past  century,  may  we  not  ask  the 
question :  Has  hydrogen  been  more  thoroughly  studied  than  nitro- 
gen ?  Hydrogen  being  the  lightest  of  all  known  gases,  how  will 
impurity  affect  its  atomic  weight  ?  There  is  only  one  answer  pos- 
sible, and  that  is,  it  will  make  the  atomic  weight  higher.  As  a 
matter  of  tact,  the  results  seem  to  tend  in  all  instances  in  that  direc- 
tion. In  physical  standards  the  material  taken  should  be  above 
suspicion.  It  is  very  unfortunate  that  the  committee  has  adopted 
this  hydrogen  standard,  especially  as  the  International  Atomic 
Weight  Commission  has  this  year  dropped  this  foolishness  for  good. 
See  Bulletin  Societ'e  Chimique  de  Paris  for  January,  1 905. 
In  the  future  only  one  table  of  atomic  weights  will  be  published, 
namely,  that  referred  to  oxygen  equal  16000.  This  has  been  used 
by  the  men  who  practiced  for  years;  bodies  such  as  the  Hungarian 
Association  for  the  Advancement  of  Science  have  long  discarded 
the  silly  hydrogen  didactic  twaddle.  Practical  German  pharmacists, 
such  as  Fischer  ot  Breslau,  have  used  these  same  weights  in  their 
