824  Lactometer  and  Fat  in  Milk  Control,    j  AmbecUr'i<Sarm' 
obtained.  The  intersection  of  line  II  with  I  shows  where  the  legal 
standard  in  Pennsylvania  limits  the  use  of  the  skimming  rule.  In 
the  writers  opinion  it  is  much  better  practice  in  Pennsylvania  for 
the  analyst  to  limit  himself  in  all  possible  cases  to  establishing  that 
a  given  adulterated  milk  is  sub-standard  rather  than  to  base  the 
legal  action  upon  the  charge  of  skimming. 
Another  limit  to  the  use  of  the  skimming  rule  as  a  guide  in 
sorting  out  mixed  milks  that  merit  detailed  examination  could  also 
be  readily  shown  were  it  possible  to  lay  off  on  the  same  axes  a  line, 
III,  representing  the  limits  separating  the  watered  milks  from  the 
unwatered  milks,  among  those  that  lie  above  the  legal  standard. 
Here  the  data  are  less  satisfactory  than  in  the  two  other  instances. 
But  the  writer  has  used,  tentatively  at  least,  a  suggestive  formula 
due  to  Bialon.12  It  may  be  urged  with  reason  that  it  does  not  rest 
upon  American  experience,  but  Bialon's  formula  may  be  not  only 
suggestive  but  also  useful  to  some  degree  until  such  time  as  Amer- 
ican experience  may  have  shown  that  Bialon's  constant  for  the 
gravity  of 'unwatered  fat-free  milks  is  different  from  or  is  the  same 
as  the  corresponding  constant  exhibited  by  the  outputs  of  large 
numbers  of  American  herds.13 
Bialon's  formula  is 
Specific  gravity  of  the  fat-free  milk, 
100  G  —  F  ,  N 
M=   :   (14) 
100  —  F/0.933 
He  places  the  lowest  gravity  in  unwatered  fat-free  milks  at  the  fig- 
ure 1.0323,  hence  for  the  poorest  unwatered  milks  his  formula  may 
be  written 
100  G  —  F  ,  n 
1.0323  =   —    (iO 
00        100  —  F/0.933  v  DJ 
Substituting  in  equation  (15)  the  value  of  G  as  given  in  (5),  and 
reducing,  Bialon's  formula  becomes : 
F  =  969.927  —  939-579  G   (16) 
The  values  in  the  following  table  have  been  calculated  from 
this  equation  (16)  : 
12  Milchwirtschaftliches  Z entralblatt ,  I,  1905,  p.  363.  See  Barthel,  Die  Me- 
thoden  zur  Unter  sue  hung  von  Milch  und  Molkerei  Produkten,  1911,  p.  134. 
13  As  already  suggested  in  footnotes  Nos.  3  and  5,  practically  every  milk 
formula  has  been  put  forth  first  in  a  form  that  was  tentative  or  was  later 
modified. 
