424 
Progress  of  Soda  Industry. 
/Am.  Jour.  Pharm. 
t    August,  1883. 
stituents  during  the  incineration.  On  analyzing  a  number  of  sheej> 
bones,  the  carbonic  acid  was  found  to  vary  in  the  different  bones  be- 
tween 2*58  and  3' 55  per  cent.,  while  in  the  bone  ash  the  variation  was^ 
between  0*68  and  1*31  per  cent.,  strong  ignition  evidently  decreasing 
the  amount.  The  sulphuric  acid,  SO3,  in  the  bone  ash,  varied  between 
0.40  and  0.90  per  cent.,  strong  ignition  showing  scarcely  any  influence 
on  the  result.  The  relation  of  the  figures  are  such  that  the  effect  of 
the  sulphuric  acid  formed  does  not  alone  explain  the  loss  of  carbonic 
acid,  but  that  also  a  conversion  of  dicalcium  into  tricalcium  phosphate^ 
as  explained  above,  must  take  ^Isice.—Zeitschr.  physioL  Chem.,  1883^ 
474-478. 
RECENT  PROGRESS  IN  THE  SODA  INDUSTRY. 
By  G.  Lunge. 
In  the  introduction  to  this  extensive  paper,  the  author  mentions  that 
although  most  of  the  subjects  have  already  been  published  elsewhere,  the 
information  is  in  many  cases  so  imperfect,  that  it  was  thought  desirable  to 
discuss  this  important  question  more  minutely.  In  the  first  place  atten- 
tion is  called  to  the  want  of  uniformity  in  specific  gravity  tables,  a  question 
whi(ih  affects,  not  only  the  soda  industry,  but  almost  all  other  branches  of 
technical  chemistry.  Messel  has  compiled  a  table  showing  the  wide  differ- 
ences in  the  specific  gravity  of  sulphuric  acid  and  ammonia  obtained  by 
various  investigators.  Squire  calls  attention  to  the  fact  that  the  tables  pub- 
lished in  books  are  drawn  up  for  pure  substances,  and  are  therefore  often 
useless  for  commercial  products.  The  author  cannot  agree  with  Messel, 
who  states  that  the  differences  can  hardly  arise  from  impurities  in  sul- 
phuric acid  made  from  sulphur. 
Referring  to  gas  generators,  the  author  quotes  as  a  novelty,  Wilson's  gas 
producer,  used  in  England  for  steel  furnaces,  copper-smelting  furnaces, 
glass  and  porcelain  furnaces,  and  applied  to  Mactear's  decomposing  fur- 
nace. 
As  to  the  progress  made  in  the  manufacture  of  sulphuric  acid  from 
pyrites,  it  is  mentioned  that  the  so-called  self-burners,  which  are  generally 
used  in  Germany,  are  now  coming  into  extensive  use  in  England.  The 
process  of  Benker  and  Lasne,  based  upon  the  introduction  of  sulphurous 
anhydride  and  steam  into  the  chamber  exit  gases  before  they  reach  the 
Gay-Lussac  tower,  does  not  appear  to  have  given  satisfactory  results.  The 
use  of  potassium  nitrate  in  the  form  of  an  acqueous  solution  has  also  been 
abandoned. 
Lovett,  in  a  paper  on  the  testing  of  noxious  vapors,  describes  a  number 
of  absorption-apparatus  and  several  forms  of  aspirator  {J.  Sac.  Chem.  In- 
dustry/, 1882,  209.) 
Referring  to  Hurter's  dynamic  theory  of  the  manufacture  of  sulphuric 
acid,  the  author  points  out  thai  it  must  be  considered  a  most  valuable 
research  in  pure  chemistry.    Hurter  attempts  to  show,  according  to  mathe- 
