ON  THE  VALUATION  OF  CHLORIDE  OF  LIME.  349 
The  following  is  the  method  he  recommends  for  applying  this 
principle  to  commercial  valuations  : — 
"  Having  obtained  a  flat-bottom  flask  or  bottle  which  will 
contain  10,000  grains  of  distilled  water  when  filled  up  to  a 
certain  mark  in  the  neck,  make  two  standard  solutions,  the  first 
by  placing  in  a  flask  or  bottle  1190  ^or  exactly  1189-97*)  grains 
of  the  purest  crystallized  ferrocyanide  of  potassium  (yellow 
prussiate  of  potash)  reduced  to  powder,  adding  distilled  w^ater 
to  dissolve  the  salt,  and  when  this  is  effected  filling  up  with 
water  to  the  mark  ;  and  having  mixed  the  solution  thoroughly, 
place  it  in  a  well-stoppered  bottle.  The  second  standard  solution 
is  made  in  the  same  manner,  substituting  for  the  ferrocyanide 
138-6  (or  exactly  138-58)  grains  of  bichromate  of  potash  which 
has  been  purified  by  recrystallization  and  fused  in  a  crucible  at 
as  low  a  heat  as  possible.  Both  these  solutions  will  keep  un- 
changed, and  will  answer  for  a  number  of  determinations  if  they 
are  preserved  in  well. stoppered  bottles,  and  the  ferrocyanide 
solution  be  kept,  when  not  in  use,  excluded  from  the  light.  Get 
a  burette  or  alkalimeter  capable  of  holding  or  delivering  1000 
grains  of  distilled  water,  and  divided  into  100  equal  divisions  ; 
also  two  small  bottles,  one  capable  of  delivering  1000  grains, 
and  the  other  500  grains  of  distilled  water  when  filled  up  to  a 
certain  mark  on  the  neck  of  each,t  which  may  both  be  readily 
made  by  filling  them  with  water,  emptying  them,  and  after  they 
have  drained  for  a  minute  or  two,  weighing  into  each  the  above 
weights  of  distilled  water ;  or,  what  will  be  sufficiently  accurate 
for  most  purposes,  pour  from  the  burette  into  100  divisions  of 
distilled  water,  and  into  the  other  50,  and  mark  with  a  file  where 
the  fluid  stands  in  the  neck  of  each  bottle.  Having  these  already, 
*  The  above  numbers  are  obtained  as  follows  ; — 35-5  parts  of  chlorine 
are  capable,  as  before  stated,  of  converting  422-44  parts  of  the  crystallized 
ferrocyanide  of  potassium  into  ferridcyanide  ;  therefore  100  parts  of  the 
former  will  convert  1189-97  parts  of  the  latter  into  the  same  compound. 
Again,  as  before  observed,  1267-32  parts  of  the  crystallized  ferrocyanide 
require  147-59  parts  of  the  bichromate  of  potash  to  convert  them  into  the 
ferridcyanide  ;  1189-97  parts,  therefore,  will  take  138-58  parts  of  that  salt 
to  produce  the  same  effect. 
•j-Two  small  pipettes  capable  of  delivering  the  above  quantities  would 
be  found  still  more  convenient. 
