526 
PREPARATION  OF  CAUSTIC  SODA. 
perhaps,  from  ten  to  twenty  different  substances,  in  a  state  of 
mechanical  admixture.  Fortunately,  this  crude  acid  is  available 
for  the  purposes  to  which  I  invite  the  attention  of  your  readers. 
Just  as  oil  is  an  anti  frictional  liquid,  so  is  phenole  pro-friction- 
al :  or,  to  state  it  more  correctly,  as  oil  appears  to  keep  surfaces 
in  motion  asunder  by  interposing  a  thin  film  between  them,  so 
phenole  appears  to  make  them  bite  and  bind,  by  bringing  them 
into  absolute  contact  (after  a  manner  of  speaking),  and  removing 
even  the  finest  film  from  between  them.  Any  one  may  convince 
himself  of  this  by  placing  a  little  upon  a  perfectly  clean  and  dry 
oil-stone,  and  then  rubbing  up  the  face  of  a  broad  chisel  upon  it. 
The  sensation  of  the  bite  (I  know  no  other  word  to  express  it) 
is  very  curious,  and  renders  any  further  explanation  unnecessa- 
ry ;  it  seems  as  if  the  stone  and  the  steel  had  absolutely  nothing 
between  them,  or  even  as  if  they  were  positively  brought  to- 
gether by  some  attractive  force.  I  have  applied  this  property 
of  carbolic  acid  to  the  following  operations  :— grinding,  filing, 
boring,  and  sawing  in  metal,  with  great  apparent  advantage. 
When  dissolved  in  fifteen  parts  by  measure  of  methylated  alcohol, 
it  forms  a  milk-white  emulsion  if  poured  into  water,  and  it  may 
be  worth  while  to  ascertain  whether  such  carbolated  water  would 
facilitate  the  ordinary  work  of  the  grindstone,  a  point  on  which 
I  am  not  able  to  speak  with  certainty.  If  any  of  your  readers 
should  experience,  as  I  did,  much  difficulty  in  obtaining  the  crude 
carbolic  acid,  I  shall  have  much  pleasure  in  indicating  the  source 
whence  mine  was  derived,  or  in  supplying  any  practical  engi- 
neer with  a  small  sample  so  long  as  ray  little  quantity  holds 
out."—  Chem.  News,  July  26,  1862. 
ON  THE  PREPARATION  OF  CAUSTIC  SODA. 
By  M.  Woehler. 
This  process  consists  simply  in  calcining  nitrate  of  soda  with 
peroxide  of  manganese.  No  chameleon  is  formed,  as  might  be 
supposed,  since  the  nitrate  decomposes  long  before  the  mixture 
can  reach  the  temperature  necessary  for  the  production  of  man- 
ganic acid. —  Chem.  JSews,  from  Annalen  der  Chemie  and 
Pharmacie. 
