Am.  Jour.  Pharm. 
May.  J 902. 
Reviews. 
239 
be  done  without  any  training  in  the  higher  mathematics.  In  gen- 
eral, references  are  given,  so  that  any  one  wishing  to  make  an 
extended  study  of  any  special  portion  may  do  so  with  little  diffi- 
culty. The  amount  of  the  subject  included,  however,  embraces 
all  that  which  is  likely  to  be  useful  to  all  chemists. 
In  the  preparation  of  the  second  edition  the  author  has  endeav- 
ored to  do  three  things:  (a)  To  bring  the  subject-matter  itself  up 
to  date  ;  (b)  to  make,  wherever  possible,  the  relations  clearer  than 
before ;  (c)  to  make  the  book  itself  more  useful  to  those  studying 
the  subject  without  an  instructor.  The  physical  meaning  of  all 
relations  is  shown,  so  that  those  who  have  not  sufficient  mathe- 
matical training  to  actually  derive  the  single  relations  will  at  least 
understand  them  and  be  able  to  apply  them  when  necessary.  Fol- 
lowing the  advice  of  Professor  Ostwald,  the  chapter  on  the  role  of 
the  ions  in  analytical  chemistr}/  has  been  given  a  place  in  Chapter 
VII  between  chemical  equilibrium  and  kinetics.  In  Chapter  X  a 
collection  of  problems  is  given  which  will  show  the  value  and  appli- 
cation of  each  important  relation  considered.  This  collection  will 
be  particularly  acceptable  to  those  studying  alone,  as  well  as  to 
others  who  have  already  studied  the  subject,  but  not  yet  attempted 
to  apply  it. 
The  following  subjects  are  treated  in  the  respective  chapters:  (1) 
Physical  chemistry,  energy,  the  factors  of  energy  and  the  methods 
for  the  determination  of  the  atomic  weight ;  (2)  the  gaseous  state  ; 
(3)  the  liquid  state;  (4)  the  solid  state;  (5)  solution;  (6)  thermo- 
chemistry; (7)  chemical  change,  (a)  equilibrium,  (J?)  the  role  of 
ions  in  analytical  chemistry,  (c)  chemical  kinetics;  (8)  the  phase- 
rule  and  the  equilibrium  of  water  in  its  phases  ;  (9)  electrochem- 
istry, the  migration  of  the  ions,  the  conductivity  of  electrolytes, 
electromotive  force,  electrolysis  and  polarization;  (10)  problems 
showing  the  value  and  application  of  the  chapters  considered. 
The  book  is  to  be  commended  most  heartily  to  every  one  having 
an  interest  in  the  principles  of  chemistry. 
Indicators  and  Test-Papers.  By  Alfred  I.  Cohn.  Second 
edition,  revised  and  enlarged.  $2.00.  New  York :  John  Wiley  & 
Sons;  London:  Chapman  &  Hall,  Limited,  1902. 
The  first  edition  of  this  book  was  favorably  reviewed  in  this 
Journal  for  January,  1900.    In  the  second  edition  the  work  has  been 
