BLACK  STAIN  FOR  WOOD. 
429 
be  substituted  for  the  pure  nitric  acid  in  larger  proportions,  and 
the  solution  may  be  obtained  as  I  have  directed  in  ray  formula 
published  by  Mr.  Sands,  in  the  Agricultural  report  for  1853,  p. 
153-5,  (and  which  I  then  copied  from  my  formula  deposited  in  the 
Smithsonian  Institute  in  1850.)  I  have  tried  the  modes  of  using 
this  reagent  suggested  by  others,  and  utterly  failed  to  approximate 
to  the  truth.  Moreover  this  is  by  half  the  most  expeditious  mode 
that  I  have  met  with,  and  the  only  one  practicable  in  the  hands  of 
a  novice.  It  is  one  that  I  devised  several  years  since,  and  have 
used  repeatedly  in  teaching  my  students.  20  lbs.  of  phosphoric 
acid  may  thus  be  easily  detected  in  an  acre  of  soil  in  a  few  hours. 
Baltimore,  May,  1855.  .American  Farmer. 
BLACK  STAIN  FOR  WOOD. 
By  C.  Karmrasch. 
The  author  having  learnt  from  Professor  AltmQller,  of  Vienna, 
that  Runge's  black  stain,  which  has  been  much  recommended  for 
some  years  as  an  ink  for  steel  pens^  furnished  an  excellent  means 
of  staining  wood  black,  was  induced  to  make  some  experiments, 
the  result  of  which  lead  him  to  recommend  it  further  for  this  pur- 
pose. 
The  ink  in  question,  which  may  be  readily  prepared  by  any  one, 
is  applied  to  the  wood  without  warming,  or  any  other  preparation, 
by  means  of  a  brush  or  sponge.  When  dry,  the  application  of  the 
dye  is  repeated,  and  three,  or  at  the  utmost  four  applications,  pro- 
duce a  deep  black  color,  which  acquires  the  highest  beauty  when 
polished  or  varnished. 
The  stain  may  be  kept  for  a  long  time  ;  and  in  simplicity  of  em- 
ployment, as  well  as  in  the  goodness  and  rapidity  of  its  results,  it 
exceeds  the  common  black  wood-stain,  which  it  certainly  equals  in 
cheapness.  The  author  has  obtained  equally  good  results  with 
the  most  different  woods,  such  as  beech,  cherry,  poplar,  lime,  fir,&c. 
The  best  method  for  the  preparation  of  the  chrome-ink,  according 
to  several  comparative  experiments,  is  the  following  : — 4  lbs.  or  2 
quarts  of  boiling  water  are  poured  over  1  oz.  of  pounded  commer- 
cial extract  of  logwood,  and  when  the  solution  is  effected,  1  drachm 
of  yellow  chromate  of  potash  is  added,  and  the  whole  well  stirred. 
