FRENCH  CEMENT. 
373 
brine  in  the  bag,  and  so  the  process  goes  on,  the  beef  expand- 
ing like  a  sponge,  and  gradually  taking  up  a  great  part  of  the 
natural  juice  that  it  had  previously  lost  in  the  salting  process. 
In  this  way  no  loss  of  juice  is  sustained  by  steeping,  and  the 
brine  left  in  the  bags,  after  a  nightly  dialysis  in  fresh  water, 
can  be  used  for  soup. 
Thoroughly  salted  beef,  without  bone,  takes  up  nearly  one- 
third  its  weight  of  juice,  anil  this  absorption  takes  place  grad- 
ually as  the  strength  of  the  brine  in  the  dialyser  becomes  re- 
duced. 
Meat  thus  treated  —  being,  in  fact,  fresh  meat — may  be 
cooked  in  a  variety  of  ways  that  are  obviously  not  available  for 
salt  meat ;  and  so  the  food  of  sailors,  and,  consequently,  their 
health,  may  be  improved  — Chem.  News,  May,  28, 
FRENCH  CEMENT. 
This  cement,  composed  of  lime  and  india-rubber,  is  very 
valuable  for  mounting  large  microscopical  preparations.  The 
principal  advantages  are — that  it  never  becomes  perfectly  hard, 
and  thus  permits  considerable  alteration  to  take  place  in  the 
fluid  contained  in  the  cell  without  the  entrance  of  air,  and  it 
adheres  very  intimately  to  glass,  even  if  it  be  perfectly  smooth 
and  unground.  If  a  glass  cover  is  to  be  affixed  to  a  large  cell 
containing  fluid,  a  small  piece  of  the  cement  is  taken  between 
the  finger  and  thumb  and  carefully  rolled  round  until  it  can  be 
drawn  out  into  a  thread  about  the  eighth  or  tenth  of  an  inch  in 
thickness  ;  this  is  applied  to  the  top  of  the  cell,  before  intro- 
ducing any  fluid,  and  slightly  pressed  down  with  the  finger  pre- 
viously moistened.  It  adheres  intimately.  The  preservative 
fluid  with  the  preparation  are  now  introduced,  and  the  cell  filled 
with  fluid,  which  indeed  is  allowed  to  rise  up  slightly  above  the 
walls.  The  glass  cover,  rather  smaller  than  the  external  dimen- 
sions of  the  cell,  and  slightly  roughened  at  the  edges,  is  to  be 
gently  breathed  upon,  and  then  one  edge  is  applied  to  the  ce- 
ment, so  that  it  may  be  allowed  to  fall  gradually  upon  the  surface 
of  the  fluid  until  it  completely  covers  the  cell,  and  a  certain 
quantity  of  the  superfluous  liquid  is  pressed  out.    Ey  the  aid  of 
