A  NEW  USE  FOR  CARBOLIC  ACID. 
525 
though  there  is  nothing  absolutely  new  in  it,  yet  this  analytical 
method  seems  to  me  to  give  all  the  information  necessary  for 
appreciating  any  sample  of  magnesia  by  the  aid  of  reagents  to 
be  found  in  every  chemist's  shop,  without  exacting  any  special 
skill  like  that  required  in  an  analysis  by  the  bichloride  of 
mercury.  Weigh  1  gramme  of  magnesia,  put  it  in  a  tared  ves- 
sel, and  dissolve  it  with  a  little  diluted  sulphuric  acid ;  the  so- 
lution should  take  place  instantaneously,  leaving  no  perceptible 
residuum.  Then  add  100  grammes  of  the  solution  to  some 
water ;  shake  it,  and  divide  into  two  equal  parts.  With  one 
portion  mix  50  grammes  of  commercial  spirits  of  wine,  which 
precipitates  the  sulphate  of  lime ;  directly  if  there  is  much  of 
it,  in  a  few  minutes  if  it  exists  in  small  proportion.  Supersatu- 
rate the  other  half  of  the  solution  with  ammonia  ;  if  the  speci- 
men contains  any  alumina  this  will  be  deposited  colored  by  ox- 
ide of  iron  ;  this  coloration  often  fails,  but  the  flakes  of  alumina 
almost  always  assume  a  dark  green  color  by  the  addition  of  a 
few  drops  of  soluble  sulphide  Chem,  News,  September  20,  1862, 
from  Repertoire  de  Chimie pure  et  Appliquee. 
A  NEW  USE  FOR  CARBOLIC  ACID. 
J.  E.  Ashby,  LL.D.,  writes  from  Enfield  to  the  Mechanics' 
Magazine  as  follows : — «  Most  persons  have  by  this  time  heard 
that  there  is  such  a  substance  as  carbolic  acid  ;  comparatively 
few  have  seen  it,  fewer  still  have  used  it,  and  no  one  (so  far  as 
I  can  find)  has  yet  noticed  a  very  remarkable  property  which  it 
possesses  in  relation  to  practical  mechanics.  For  the  informa- 
tion of  those  to  whom  the  substance  itself  is  unknown,  a  word 
or  two  will  be  sufficient  to  introduce  it  to  their  notice.  Carbolic 
acid  is  one  of  the  products  of  the  destructive  distillation  of  coal, 
and  till  within  a  few  years  vast  quantities  of  it  were  utterly 
wasted.  When  perfectly  pure  it  is  a  white  crystalline  solid, 
which  by  absorbing  water  soon  changes  into  a  colorless  refrac- 
tive liquid,  having  a  faint  odor  of  roses  and  tar.  It  is  not  an  acid 
in  the  popular  sense,  not  being  either  sour  or  corrosive,  and 
should  therefore,  perhaps,  be  generally  designated  by  its  other 
title  of  phenole.  Crude  carbolic  acid  may  be  obtained  in  bulk 
for  a  shilling  per  gallon,  and  is  a  daik  tarry  liquid,  containing, 
