000 
Mr.  P.  S.  Barlow  on  the  Osmotic 
at  0°  C.  An  ice-chest  was  made  or  tin  in  the  form  of  a  double 
box,  the  inner  box  in  which  the  cells  were  to  be  placed  being 
about  three  inches  from  the  walls  of  the  outer  on  all  sides. 
The  top  was  closed  by  a  deep  tray  filled  with  ice.  The  inner 
box  could  thus  be  surrounded  by  broken  ice.  The  outside 
was  covered  with  three  or  four  layers  of  cotton-wool.  By 
means  of  a  deep  groove  which  was  surrounded  by  the  ice, 
the  inner  box  was  connected  to  the  surface  of  the  outer  one, 
and  in  this  groove  lay  the  horizontal  glass  tube  which  con- 
nected the  gauge  to  the  cell.  The  gauge  could  thus  be 
outside  the  case. 
The  ice-chest  wTas  made  so  that  two  experiments  could  be 
carried  on  together,  but  it  was  only  possible  to  get  cell  B  in. 
to  work.  Several  days  were  spent  in  attempts  with  B  I.  and 
B II.,  but  without  success  ;  and  their  use  for  the  purposes  of 
this  paper  had  to  be  discarded.  It  was  unfortunate  to  be 
thus  reduced  to  one  cell,  as  the  time  at  my  disposal  for  the 
work  was  limited  ;  and  each  reading  obtained  (for  a  steady 
value)  required  a  week's  time.  Cell  B  in.  is  the  newest 
type  of  the  brass  cells  used,  and  has  worked  the  best.  The 
following  is  a  diagram.  The  section  at  right  angles  to  the 
paper  is  circular. 
Fig-.  2. 
B 
SOLVENT 
Solut/on 
To  QAUC£ 
The  opening  A  was  connected  to  an  adjustable  mercury- 
gauge,  or  was  open  to  the  air  through  a  large  calcium- 
chloride  tube.  B  was  closed  by  thick  rubber  tubing.  The 
membrane  stretched  between  the  flanges  was  backed  by 
perforated  zinc.  In  these  experiments  A  was  connected  by 
a  long  piece  of  tubing  to  a  calcium -chloride  tube  which  was 
kept  outside  the  ice-chest,  the  tubing  being  brought  through 
the  groove  connecting  the  two  boxes. 
A  thermometer  passing  through  the  ice-tray  which  formed 
the  lid  of  the  chest  was  placed  so  as  to  be  near  the  osmotic 
