486  Gleanings  from  the  European  Journals.  {AVo°v.ai  lira** 
a  very  copious  evolution  of  inflammable  gases  takes  place.  If  a  few 
cubic  centimeters  of  nitrobenzol  are  heated  in  a  long  test-tube  with 
finely  powdered  potassa,  the  volume  of  the  extricated  gases  is  suffi- 
cient to  produce,  on  ignition,  a  flame  twelve  to  eighteen  inches  high. 
—Pharm.  Centralh.,  1873,  No.  39  from  Polyt.  Notizbl 
Testing  Sulphate  of  Aluminum. — This  salt  sometimes  contains  free 
sulphuric  acid,  which  can  be  ascertained  by  treating  the  salt  with  alco- 
hol, in  which  it  is  insoluble,  but  which  dissolves  the  uncombined  acid, 
acquiring  thereby  an  acid  reaction.  Pure  sulphate  of  aluminum  im- 
parts to  decoction  of  logwood  a  dark  violet  color,  which  changes  to 
brown  in  the  presence  of  free  acid. — Ibid.,  from  Beim.  Fdrberzeitung. 
Bed  Brown  Wash  for  Wood. — 1  lb.  of  sulphate  of  copper  is  dis- 
solved in  8  lbs.  of  water,  and  the  solution  applied  to  the  wood  with 
an  ordinary  brush  ;  this  is  to  be  followed  by  a  solution  of  J  lb.  fer- 
rocyariide  of  potassium  in  8  lbs.  of  water.  The  ferrocyanide  of  cop- 
per thus  deposited  upon  the  wood  fibr  «  is  not  only  not  altered  by  at- 
mospheric influences,  but  it  tends  also  to  preserve  the  wood  from  the 
growth  upon  it  of  moss,  lichens,  fun^i,  and  from  the  attacks  of  in- 
sects. The  color  may  be  darkened  or  lightened  by  increasing  or  de- 
creasing the  strength  of  the  solutions,  and  the  wash  will  be  more  per- 
manent if  the  wood  afterwards  receives  a  coat  of  boiled  linseed  oil 
or  varnish. — Ibid. 
An  Emulsion  of  Petroleum  with  Soapwort  Decoction  has  been  pro- 
posed by  Jordery  to  lessen  its  inflammability  Avhile  being  transported 
or  stored.  A  concentrated  decoction  of  soapwort  will,  by  constant 
stirring,  readily  emulsify  twenty  five  times  its  volume  of  petroleum, 
and  this  mixture  gradually  becomes  firmer  in  consistence.  In  this 
condition  petroleum  does  not  readily  penetrate  into  the  fissures  of  the 
barrels,  and  its  volatility  is  considerably  lessened.  The  addition  of 
a  few  drops  of  carbolic  acid,  or  of  a  somewhat  larger  quantity  of 
crystallizable  acetic  acid,  renders  the  mass  liquid  again  in  a  few  min- 
utes, and  the  petroleum  rises  clear  and  limpid  to  the  surface  of  the 
aqueous  solution. 
In  a  report  to  the  Conseil  de  salubrite  de  la  Seine,  Mr,  Troost 
speaks  favorably  of  this  invention,  and  states  that  it  deserves  the 
attention  of  all  interested  in  the  sale  of  petroleum,  notwithstanding 
the  process  in  its  present  state  does  not  yet  appear  to  be  adapted 
