Am.  Jour.  Pharm. ) 
November,  1900.  j 
Technical  Chemistry. 
549 
device  the  fuel  is  burned  directly  to  carbonic  dioxide  during  the 
heating,  or  air  blast  period,  by  using  extra  high  blast  pressure,  and 
skilfully  distributing  its  contact  with  the  fuel.  This  increases  the 
gas  yield  by  nearly  100  per  cent.,  and  reduces  the  total  loss  of  the 
heat  value  of  the  fuel  from  55  to  only  18  per  cent.  During  the 
past  year  a  plant  has  been  installed  in  Pittsburg  for  the  conversion 
of  coal  into  fuel  gas,  utilizing  a  radically  new  method,  which  also 
bids  fair  to  solve  this  important  fuel  question,  and  the  result  of  this 
experiment  is  awaited  with  intense  interest. 
In  many  instances,  where  petroleum  has  been  used  as  fuel,  its 
recent  increased  cost  has  forced  its  abandonment.  This  has  made 
the  discovery  of  an  equally  convenient  and  efficient  fuel  a  great 
desideratum.  Fortunately  such  a  substitute  for  oil  has  been  found 
in  the  use  of  finely-powdered  bituminous  coal,  injected  into  the 
furnace  with  an  air  blast  just  as  oil  is  used.  The  coal  is  thoroughly 
dried  and  ground  very  fine.  Its  only  drawback  seems  to  be  almost 
explosive  combustibility,  rendering  its  storage  unsafe.  The  tem- 
perature attainable  by  this  means  seems  to  be  almost  equal  to  that 
with  oil,  and  in  respect  to  cost  and  some  other  considerations  it  is 
more  advantageous. 
During  the  year  a  wonderful  growth  in  the  manufacture  of  Port- 
land cement  has  taken  place  in  the  United  States,  so  that  within  the 
coming  decade  we  may  reasonably  expect  to  supply  all  of  the  home 
consumption  and  probably  a  great  part  of  that  used  in  other  coun- 
tries. The  principal  improvement  in  methods  has  been  the  general 
introduction  of  the  automatic  rotary  kiln  or  burning  furnace.  These 
consist  of  inclined  steel  cylindrical  shells,  about  6o  feet  long, 
mounted  on  rolls  and  lined  with  magnesia  brick.  The  cement  mix- 
ture is  pumped  with  water  or  fed  dry  by  a  screw  into  the  upper  end 
and  falls  out  as  burned  clinkers  continuously  at  the  lower  end.  The 
fuel  used  is  oil,  gas,  or  powdered  coal,  the  process  is  continuous  and 
requires  a  minimum  of  manual  labor.  The  success  of  this  invention, 
which  has  been  brought  about  commercially  in  the  United  States 
first,  has  been  so  pronounced  that  American  experts  have  been 
called  to  the  oldest  and  best  cement-producing  districts  in  the 
world  to  reconstruct  their  plants  on  the  new  lines. 
In  the  manufacture  of  sulphuric  acid,  1899  has  seen  the  successful 
beginning  of  the  greatest  revolution  since  this  acid  began  to  be  pro- 
duced on  a  large  scale,  namely,  the  production  of  sulphuric  trioxide, 
