442 
BAKER'S  BREAD  OF  PHILADELPHIA. 
it  is  necessary  therefore  to  exhaust  every  precaution  in  the  puri- 
fication of  the  original  materials,  particularly  the  sodium ;  to 
analyse  it,  it  is  put  with  a  few  drops  of  nitric  acid  into  a  small 
crucible  of  Sevres  porcelain,  and  a  very  small  quantity  of  pure 
hydrofluoric  acid  is  added  (silicium,  when  strongly  heated,  resists 
the  action  of  hydrofluoric  acid  and  nitromuriatic  acid  ;)  it  should 
dissolve  entirely,  and  the  liquid,  when  evaporated  to  dryness, 
should  leave  no  trace  of  ferruginous  matter. 
Silicium  alloys  metals,  especially  copper,  to  which  it  communi- 
cates a  hardness  so  great  that  the  metal  resists  the  action  of  the 
file.    This  is  copper-steel. 
Titanium,  obtained  by  exactly  similar  processes  and  calcined 
in  crucibles  of  alumina,  is  infusible  at  a  temperature  which  causes 
the  vaporization  of  platinum ;  it  resembles  very  iridescent  spe- 
cular iron  ore,  and  crystallizes  in  prisms  with  a  square  base. — 
Ohem.  Graz.,  June,  1855,  from  Comptes  Rendus,  April  30th, 
1855,  p.  1034. 
CHEMICAL  EXAMINATION  OF  THE  BAKERS'  BREAD  OF 
PHILADELPHIA. 
By  Charles  M.  Wetherill,  Ph.D.,  M.D. 
Bread  is  the  most  important  element  of  our  food,  not  only  for 
its  nutritive  properties,  but  because  it  is  susceptible  of  adultera- 
tions, which,  though  they  may  be  small  in  amount,  are  neverthe- 
less so  constantly  taken  into  the  system  that  they  cannot  fail  in 
the  end  to  prove  detrimental  to  health.  We  find  accordingly  a 
very  general  prejudice  against  the  wholesomeness  of  bakers', 
bread,  and  the  fault  is  attributed  to  the  use  of  alum,  which  is 
supposed  to  be  the  reason  that  such  bread  presents  a  finer  ap- 
pearance than  that  made  at  home.  Although  this  is  a  yulgar 
error,  since  such  fine  appearance  is  the  result  of  art,  and  the 
bread  need  not  contain  any  different  ingredients  from  that  which 
is  home-made,  bakers  have  thrown  themselves  open  to  suspicion, 
for  wherever  the  bread  has  been  examined  on  a  large  scale, 
adulterations  have  been  found  present,  and,  in  some  places,  are 
of  universal  use.  Mr.  Normandy,  author  of  the  Commercial 
Hand  Book  of  Chemical  Analysis,  states  in  the  same  work  that 
"  bread  really  pure,  that  is,  made  altogether  of  genuine  wheat 
