198  Reviews  and  Bibliographical  Notices,  {^i^Sg™1- 
REVIEWS  AND  BIBLIOGRAPHICAL  NOTICES. 
First  Course  in  Microchemical  Analysis.  By  Carl  Gustav  Hin- 
richs.  With  atlas.  St.  Louis,  Mo.,  1904.  New  York  and  Leipzig: 
Lemcke  and  Buechner. 
About  a  year  ago  Prof.  Gustav  D.  Hinrichs,  the  well-known  author 
on  atomic  weights  and  general  chemistry,  requested  his  son  to  work 
out  a  course  in  microchemical  analysis  which  should  not  require 
the  use  of  sulphuretted  hydrogen,  intending  to  use  it  in  connection 
with  a  work  on  microchemical  analysis  which  he  had  contemplated 
publishing.  Upon  the  completion  of  the  work  by  his  son,  the  elder 
Hinrichs  insisted  that  his  son's  name  appear  as  author,  he  writing, 
an  introduction  to  crystallographic  chemistry. 
Microchemical  analysis  is  defined  as  the  chemical  identification  of 
minimal  amounts  of  substance  in  concentrated  solutions.  The 
amount  of  substance  used  in  such  analysis  is  very  small,  usually  a 
tenth  of  a  milligramme  giving  sharp  and  positive  results. 
While  it  is  known  to  a  certain  extent  that  the  crystalline  form  of 
a  substance  is  an  extremely  important  physical  property  in  its  iden- 
tification, yet  chemists  have  not  generally  confirmed  their  results  by 
microscopic  examinations  of  chemicals  or  precipitates.  This  work 
by  Hinrichs  will  draw  attention  again  to  this  important  subject. 
Considerable  work  has  already  been  accomplished  along  this  line, 
there  being  at  least  one  rather  comprehensive  German  work  on  the 
subject.  The  plates  reproduced  from  the  works  of  Behrens,  Haus- 
hofer,  Lehman,  and  others,  as  well  as  the  original  drawings  of  the 
author,  are  of  considerable  assistance  in  connection  with  the  text. 
In  the  present  work  the  author  has  considered  the  substances  usu- 
ally considered  in  a  complete  course  of  qualitative  analysis. 
Another  work  covering  Dr.  Hinrichs's  researches  on  complex 
compounds  and  mixtures,  as  well  as  organic  compounds,  is  in  prep- 
aration. 
The  introduction  to  crystallographic  chemistry,  by  Dr.  Gustav  D. 
Hinrichs,  is  particularly  valuable  and  unusually  clear. 
We  commend  the  present  work  for  its  originality  and  usefulness, 
to  chemists  and  pharmacists,  and  all  interested  in  microchemical 
analysis. 
