Am.  Jour.  Pharm. ) 
May,  1883.  j" 
The  Lactometer. 
245 
mated  in  making  a  scale.  The  table  here  presented  has  been  made 
ifrom  quite  a  number  of  observations,  and  a  lactometer  scale  made  to 
correspond  with  it,  representing  the  percentage  of  solid  matter,  will 
be  found  to  give  results  closely  coinciding  with  an  actual  analysis. 
The  specific  gravity  of  1*0320  is  taken  as  a  standard  for  pure  milk 
;after  being  skimmed,  and  the  amount  of  solid  matter  it  contains  equal 
.to  14  per.  cent,  including  the  fat  held  in  suspension. 
Specific  Gravity. 
Per  cent,  solids. 
Per  cent,  water. 
1  UoZU 
A- 
3-0297 
13- 
7-7 
1-0291 
12-7 
10- 
1-0280 
12- 
14-3 
1-0267 
11-6 
20- 
1-0251 
11- 
27-5 
1-0246 
10-8 
30- 
1-0229 
10- 
40- 
1-0213 
9'3 
50- 
1-0206 
9- 
55-5 
1-0200 
8-7 
60- 
1-0188 
8-2 
70* 
1-0183 
8- 
75- 
1-0178 
7-7 
80- 
1-0168 
7-3 
90- 
1-0160 
7- 
100- 
In  using  the  lactometer  made  according  to  this  scale,  it  is  first  neces- 
;sary  to  fill,  with  the  milk  to  be  tested,  ajar  graduated  to  indicate  the 
percentage  of  cream,  allow  it  to  stand  for  a  length  of  time  sufficient 
for  the  cream  to  rise,  this  will  be  from  6  to  8  hours,  when  a  distinct 
•demarcation  will  allow  the  percentage  to  be  readily  read  off.  By 
means  of  a  pipette  the  cream  is  to  be  removed,  and  the  lactometer 
floated  in  the  milk,  when  the  per  cent,  of  solids  can  be  seen  without 
any  further  operation.  This  is  a  very  easy  process  and  can  be  con- 
ducted by  the  consumer  or  ordinary  milkman,  and  will  give  results 
that  are  reliable  enough  for  all  practical  purposes. 
Another  method  intended  for  those  who  buy  milk  in  large  quantities 
from  surrounding  dairies  is  the  one  here  described.  The  instruments 
required  are  two  graduated  jars  for  showing  the  percentage  of  cream, 
called  creamometers,  one  per  cent,  glass  and  a  lactometer.  Fill  one 
of  the  creamometers  to  the  mark  designated  10  with  milk  that  is 
known  to  be  pure  and  drawn  from  several  cows.  This  will  be  the 
standard  for  pure  milk  for  that  day.  Fill  the  other  creamometer  to 
the  same  mark  with  the  milk  to  be  tested,  and  set  both  aside  for  the 
