822 
Lactometer  and  Fat  in  Milk  Control.  \Am^°^\^rmm 
TABLE  I. 
%/af 
%fat 
*\  hp n  fir 
T  cici nwi,ptpr  ypclA- 
calculated  by 
ml riArlnfpd,  hv 
lr  WfrL-  vvvxm  V  t-  Li/  L/^y 
gravity  at  6o°  F. 
ing  at  6o°  F. 
formula  (9) 
formula  (11) 
T  C\0  C 
2  R 
T  C\0(\ 
2  C\ 
2  n 
I  027 
27 
5-u 
O  T 
3-1 
O  T 
3-1 
1 .029 
29 
3-2 
3-2 
t  rv2r» 
"2  "2 
"2  "2 
1. 03 1 
31 
3-4 
3-4 
1.03^ 
"22 
1  c 
-2  d 
00 
65 
2  6 
5-u 
T  r\i  A 
04 
07 
0/ 
1-035 
35 
3-8 
3.8 
1.036 
36 
3-9 
3-9 
1.037 
37 
4.0 
4.0 
•  1.038 
38 
4-1 
4-1 
1.039 
39 
4.2 
4.2 
1.040 
40 
4-3 
4-3 
Upon  inspection  of  this  table,  a  surprisingly  simple  relation  be- 
tween the  lactometer  reading  and  the  fat  per  cent,  becomes  evident. 
The  numerical  values  for  the  fat  may  be  obtained  by  adding  3  to 
the  lactometer  reading  and  then  dividing  by  10.  This  is  expressed 
by  a  much  simpler  formula  than  either  of  those  originally  used  to 
calculate  the  values  of  F  set  forth  in  Table  I : 
F        K        3-   (12) 
10  v 
From  the  derivation  of  formulae  (9)  and  (11),  and  hence  of  this 
simple  formula  (12),  it  follows  that  any  one  of  the  fat  values 
calculated  by  formula  (12)  is  the  lowest  or  minimum  fat  per- 
centage to  be  expected  in  an  unskimmed  mixed  milk  that  has  ex- 
hibited the  corresponding  lactometer  reading.  As  an  example  of 
the  use  of  this  formula,  consider  a  mixed  milk  found  to  have  a 
lactometer  reading  of  32 ;  the  minimum  fat  per  cent,  in  such  a  milk 
if  it  is  above  suspicion  of  skimming  is 
(32  +  3)        10  ==  3-5%- 
Should  the  milk  be  found  by  actual  analysis  to  contain  less  than 
3.5  per  cent,  it  should  be  set  aside  for  further  consideration  be- 
cause it  is  not  above  suspicion  of  being  skimmed. 
