194  Miscellaneous  Implements  Exliihited  at  Park  Kopal. 
their  axes  parallel,  and  in  the  same  plane,  and  separated  about 
one-eighth  of  an  inch  from  one  another.  The  c}dinders  are 
internally  heated  by  steam,  maintained  at  40  lb.  pressure,  to 
a surface  temperature  of  220-230"  F.  They  rotate  in  the 
direction  shown  by  the  arrows  in  Fig.  9 at  a speed  of  six  or 
seven  revolutions  a minute.  The  milk  is  fed  gradually  from 
a perforated  pipe  overhead  into  the  trough  formed  between 
the  two  rollers.  It  is  prevented  from  falling  through  the  space 
between  the  two  cylinders  by  the  rapid  generation  of  steam 
from  the  water  in  the  milk,  but  a thin  uniform  film  of  semi- 
dried  milk  adheres  on  the  surface  of  each  cylinder  and  is 
carried  thereon  for  about  half  a revolution.  By  the  time  the 
milk  is  almost  dry  it  reaches  the  point  where  the  edges  of  the 
stripping  knives  (r)  rest  upon  the  surface  of  the  cylinders.  These 
knives  remove  the  film  of  milk  in  thin  continuous  sheets  (2^) 
which  become  dry  instantly  u])on  cooling.  The  dry  milk  is 
then  reduced  to  uniform  ])owder  by  being  passed  through  a sieve. 
