GLEANINGS  FROM  THE  FRENCH  JOURNALS.  319 
bility,  and  in  Schweizer's  ammoniated  copper  it  merely  swells 
up  ;  it  has  become  insoluble.  The  hulls  of  starch  prevent  the 
amylogene  of  DelfFs  from  passing  into  the  insoluble  modifica- 
tion.—(Schweiz.  Zeitschr.  f.  Ph.  v.  185-191.) 
GLEANINGS  FROM  THE  FRENCH  JOURNALS. 
By  the  Editor. 
Percolation  under  strong  pressure. — M.  Signoret,^Pharmacien 
of  Paris,  has  suggested  an  apparatus  for  extraction,  in  which  it 
is  proposed  to  hasten  the  process  of  percolation,  by  employing 
the  force  of  compressed  air  upon  the  surface  of  the  liquid  in  the 
percolator.  The  apparatus  consists  of  a  reservoir  of  metal  for 
the  compressed  air,  of  such  strength  as  to  resist  from  two  to 
eight  atmospheres,  according  to  the  force  desired.  Attached  to 
this  is  a  forcing  pump,  worked  by  a  lever.  On  four  opposite 
points,  in  the  sides  of  the  reservoir,  are  placed  four  stop. cocks, 
with  coupling  screws,  for  attaching  tubes  connecting  the  reser- 
voir with  the  tops  of  four  percolators. 
In  employing  the  apparatus,  the  material  in  powder  is  put  in 
the  percolator,  perhaps  previously  moistened,  and  the  men- 
struum poured  upon  it,  and  then  the  pressure  of  the  reservoir 
brought  to  bear  upon  its  surface.  M.  Signoret  believes  that  by 
this  mode  and  arrangement,  substances  are  more  thoroughly  and 
quickly  exhausted  than  by  maceration  or  ordinary  displacement. 
Even  flour  of  mustard,  mixed  with  an  equal  bulk  of  sand,  can  be 
exhausted.  Wine  of  cinchona  was  made  in  twenty  minutes 
before  a  committee,  who  examined  the  apparatus.  The  price  is 
quoted  as  from  200  to  300  francs,  according  to  whether  one  cr 
four  percolators  are  attached  to  the  reservoir. — Repertoire  de 
Pharmacie,  MarSy  1861. 
Varnish  to  prevent  rust  in  iron  and  steel. — M.  A.  Vogel  sug- 
gests that  the  oxidation  of  steel  and  iron  instruments  is  very 
perfectly  prevented  by  coating  them  with  a  varnish  made  by 
dissolving  one  part  of  White  Wax  in  15  parts  of  Benzin,  and 
applying  it  by  means  of  a  brush.  The  very  thin  layer  of  wax 
forms  a  perfect  covering  for  bright  instruments,  and  when 
needed  is  easily  removed. — Repertoire  de  Pharm, 
