576  Obituary, 
ary,  1836,  shortly  after  the  publication  of  the  first  part  of  that  work,  containing  the 
simple  drugs  and  the  chemicals  manufactured  on  a  large  scale.  The  second  part  by 
Mohr  was  published  in  1845,  anc^  contained  the  formulary  of  galenical  and  chem- 
ical preparations  of  the  various  pharmacopoeias  and  dispensatories  in  use  during  the 
preceding  seventy  or  eighty  years,  and  including  of  American  works  the  United 
States  Pharmacopoeias  of  1820  and  1830,  Coxe's  American  Dispensatory  and  Ellis' 
Formulary.  This  was  quickly  followed,  in  1846,  by  his  "  Pharmaceutische  Tech- 
nik,"  which  was  translated  into  the  English  language  by  Professor  Redwood,  and 
edited  for  the  use  of  American  pharmacists  by  Professor  Procter  in  1848,  under  the 
title  of  "  Practical  Pharmacy."  About  the  same  time  Mohr  wrote  his  commentary 
on  the  Prussian  Pharmacopoeia,  the  first  volume  of  which  appeared  in  1847,  a  work 
characterized  by  critical  analysis  of  the  statements  and  processes  of  the  pharma- 
copoeia. A  smaller  volume  on  the  dispensing  of  medicines  (Receptirkunst),  which, 
however,  is  mainly  intended  for  the  use  of  physicians,  completes  (1854)  the  list  of 
his  separate  pharmaceutical  works. 
But  his  numerous  contributions  to  the  pharmaceutical  journals  of  Germany  were 
also  of  great  importance,  and  embraced  processes  as  well  as  manipulations  and  appa- 
ratus, such  as  extracts,  bitter  almond  water,  benzoic  acid,  morphia,  filters,  cork-borers, 
specific  gravity  balances,  smelting  furnaces,  Marsh's  apparatus,  and  many  other 
subjects.  Many  of  the  apparatus  and  processes  invented  or  perfected  by  him  have 
been  pretty  generally  adopted  throughout  the  civilized  world,  and  this  is  more  par- 
ticularly the  case  with  the  numerous  apparatus,  contrivances  and  processes  worked 
out  by  him  in  the  department  of  volumetric  analysis,  which  had  been  introduced  by 
Gay-Lussac,  Marguerite  and  others,  but  was  brought  through  Mohr  to  such  a  state 
of  perfection  that  it  has,  in  a  great  measure,  taken  the  place  of  the  gravimetric 
methods.  His  work  on  measure-analysis  (Titrirmethode)  made  its  first  appearance 
in  1853;  since  then  four  revised  and  enlarged  editions  have  been  published,  and  to 
the  present  time  it  is  regarded  as  the  standard  work  in  this  particular  branch. 
It  was,  however,  not  only  the  practical  and  analytical  department  of  chemistry 
that  received  his  attention,  but  likewise  the  theory  of  the  science.  Aside  from  the 
many  essays  contributed  to  journals,  and  aside  from  the  work  on  measure  analysis, 
his  most  important  work  on  theoretical  chemistry  is  that  on  the  "mechanical  theory 
of  chemical  affinity,"  which  appeared  in  1868. 
Since  about  1 857  Mohr  devoted  much  of  his  time  to  geological  investigations, 
and  already,  in  1866,  appeared  from  his  fruitful  pen  a  "history  of  the  earth,"  in 
which  he  embodied  novel  views  on  the  origin  of  coal,  the  deposition  of  lime  in  the 
sea  through  the  agency  of  plants,  the  occurrence  of  magnetic  iron  in  basalt,  and  of 
metallic  iron  in  meteorites,  etc. 
Mohr's  works  are  characterized  by  clearness,  comprehensiveness  and  attractive- 
ness. His  learning  was  duly  appreciated  by  scientists,  and  he  was  a  member  of 
many  learned  societies.  By  his  death  the  Philadelphia  College  of  Pharmacy  loses  one 
of  its  valued  honorary  members.  It  seems  strange  to  us  that  a  man  of  his  general 
scientific  and  special  pharmaceutical  knowledge  and  learning  was  never  selected  as  a 
member  of  the  commissions  entrusted  with  the  various  revisions  of  the  pharmaco- 
poeia of  his  native  country. 
{Am.  Tour.  Pharm. 
Nov.,  1879. 
