AmbJe°cU,r'i9Sarm' }   Lactometer  and  Fat  in  Milk  Control.  821 
Transforming  equation  (3),  it  may  be  made  to  assume  the  form, 
_  3-941  (100  G—  ioo) 
Substituting  into  (6)  the  value  for  G  from  (5),  equation  (3)  finally 
may  be  made  to  assume  the  form, 
394-1  L 
L  +  1000 K1) 
Equating  the  values  for  T  as  given  in  (1)  and  (7),  one  obtains 
T39f-T  L    =0.25  L+1.2F  v  (8) 
L  +  1000  J      1  V  J 
which  reduces  to 
328.42  l  _p2o8  L    (  ) 
L  +  1000  0  w 
This  formula  meets  the  requirements  of  the  case  since  it  involves 
only  the  lactometer  reading  L  and  the  fat  per  cent.  F,  and  by  it 
mixed  milks  suspicious  of  skimming  will  be  indicated. 
Another  formula  that  the  writer  has  used  as  a  check  upon  the 
numerical  results  from  (9),  was  developed  by  substituting  the  value 
for  L  as  given  in  (4)  into  equation  (1)  and  then  equating  the  right 
hand  member  of  the  resulting  equation,  which  is, 
m  S    (lOO  G    IOO)  /  \ 
T  =  —  <  +  %  F    (10) 
with  the  right  hand  member  of  equation  (6).  After  simplifying 
one  then  obtains  the  formula 
F  =  2.083^  (I0O  G—  100) 
(11) 
The  numerical  results  calculated  by  each  of  these  formulae 
are  given  in  the  following  table.  The  values  found  thus  for  F  have 
been  rounded  off  so  that  they  might  not  exhibit  fictitious  accur- 
acy.10 
10  "The  fat  calculated  from  the  specific  gravity  and  total  solids  almost 
invariably  agrees  within  0.2  per  cent,  with  the  determination  made  by  the  ap- 
propriate method."  Richmond,  Dairy  Chem.,  p.  69. 
