168 
ON  THE  PREPARATION  OF  DRYING  OIL. 
exposed,  the  receiver  did  not  require  to  be  cooled  until  after  six 
hours'  working,  and  even  then  only  by  wrapping  a  wet  cloth 
round  the  neck.  The  distillate  was  removed  from  time  to  time, 
and  tested  as  to  its  purity  and  specific  gravity.  The  first  5  oz. 
that  passed  had  a  specific  gravity  of  1-20,  and  exhibited  no 
impurity  except  a  considerable  quantity  of  sulphurous  acid.  The 
second  portion  of  oz.  of  distillate,  with  a  specific  gravity  of 
1-75.  still  contained  a  trace  of  sulphurous  acid.  A  third  portion 
of  2  J  oz.  was  pure,  and  had  a  specific  gravity  of  1*850. 
Fourth  portion  of  1|-  lb.  spec.  grav.  1-855 
Fifth  portion  of  13  oz,  spec.  grav.  1-860 
Sixth  portion  of      9     oz.  spec.  grav.  1-885 
With  this  the  distillation  was  concluded,  to  enable  the  contents 
of  the  retort  to  be  examined.  The  uninjured  retort  contained 
the  remainder  of  the  sulphuric  acid  as  a  simple  fluid  with  a  white 
sediment  (persulphate  of  iron,)  from  which  no  doubt  \  lb.  of 
pure  distillate  might  still  have  been  obtained. 
In  such  distillation,  particular  attention  is  to  be  paid  to  the 
quality  of  the  retort.  It  is  always  advisable  to  anneal  the  retort 
before  using  it,  by  heating  it  as  strongly  as  possible  in  the  sand 
bath,  and  letting  it  cool  slowly  and  completely  therein  Chem. 
Gf-az.,  Nov.  15,  1856,  from  Neues  Jahrbuchr  fur.  Pharm. 
ON  THE  PREPARATION  OF  DRYING  OIL. 
By  Prof.  R.  Wagner. 
The  author  repeatedly  prepared  protoborate  of  manganese  for 
lacquerers,  in  accordance  with  the  directions  of  Barruel  and 
Jean.  He  effected  its  precipitation  whilst  hot,  and  thus  obtained 
it  of  a  coffee-brown  color,  and  consequently  containing  much 
oxide,  but  still  always  of  remarkable  efficacy.  As,  however, 
Barruel  and  Jean  expressly  observe  that  the  action  is  proper  to 
the  protosalts,  the  author  endeavored  to  obtain  it  perfectly  free 
from  oxide,  and  for  this  purpose  effected  the  precipitation  with 
borax  cold.  He  obtained  a  snow-white  powder,  but  this  furnished 
no  varnish.  He  therefore  returned  to  the  previous  mode  of 
preparation  with  the  assistance  of  heat,  and  found  that  it  was 
obtained  of  the  darkest  brown,  and  also  of  the  strongest  action, 
