546  Technical  Chemistry.  . 
general  introduction  of  the  Jones  mixer  for  receiving  the  molten 
pig  metal  direct  from  the  furnace,  thus  saving  its  contained  heat  and 
doing  away  with  cupolas  for  melting  the  iron  previous  to  its  treat- 
ment in  the  converter.  This  method  effects  not  only  a  saving  in 
heat  or  fuel,  but  a  greater  gain  in  the  cost  of  handling  the  iron.  It 
has  been  found  that  only  about  one  laborer  in  a  hundred  can  endure 
the  strain  of  continuously  handling  the  heavy  pigs  of  metal  at  the 
blast  furnace  in  their  removal  from  the  sand  moulds  and  loading  on 
cars.  The  doing  away  with  this  severe  labor  by  the  direct  use  of 
hot  metal  in  the  Bessemer  plant  and  by  the  use  of  the  Uehling 
casting  machine  seems,  therefore,  a  gain  to  humanity  as  well  as  in 
the  money  value  saved.  The  basic  converter  still  fails  to  gain  a 
permanent  foothold  in  this  country,  and,  because  of  our  immense 
deposits  of  pure  ore  and  beds  of  phosphate  rock,  and  of  the  con- 
tinued encroachments  of  the  open-hearth  process,  probably  never 
will. 
The  metallurgy  of  copper  has  undergone  changes  similar  to 
those  of  iron,  only  in  a  much  smaller  degree.  The  most  important 
of  these  are  the  increased  use  of  the  Bessemer  converter  in  refining 
mattes,  and  an  increased  output  of  electrolytically  refined  metal. 
The  general  use  of  a  gold-bearing  material  as  a  lining  for  the  con. 
verter  in  matte  Bessemerizing  has  effected  a  material  economy.  In 
roasters  for  copper  sulphide  ores,  several  new  devices  have  gained 
general  use.  A  Denver-made  modification  of  the  old  Spence  fur- 
nace, with  its  numerous  beds  and  automatic  plow  rakes,  in  which 
the  operating  chains  are  placed  upon  the  exterior  of  the  hearth,  and 
the  Herreshoff  furnace,  consisting  of  a  vertical  cylinder  with  hori- 
zontal diaphragms  or  beds  and  rakes  operated  by  a  central  shaft, 
have  perhaps  received  the  largest  installment  during  the  year.  A 
plant  of  considerable  size  to  operate  the  Hoepfner  process  of  refin- 
ing copper  has  been  in  operation  for  some  time,  but  reliable  cost 
data  are  not  at  hand.  This  process  depends  upon  dissolving  the 
oxidized  metals  with  cupric  chloride  and  electrolyzing  the  chloride 
solution.  The  process  was  tried  at  the  Brooklyn  experimental  plant 
of  a  copper-nickel  refining  company  some  years  ago,  but  was 
abandoned. 
In  the  metallurgy  of  nickel  the  principal  event  has  been  the  in- 
stallation in  England  of  a  considerable  plant  to  use  the  Mond  pro- 
cess of  refining  by  carbonic  oxide,  and  of  a  plant  in  this  country 
