802  Industrial  Organic  Chemistry.  {Xm'^\^rm' 
Eng.  Chemistry  for  May,  1918,  is  still  in  a  purely  experimental  stage 
but  it  has  much  promise. 
One  of  the  newer  uses  of  essential  oils  which  has  particularly 
stimulated  the  production  in  the  last  few  years  of  pine  oil  in  the 
South  is  for  the  ore  flotation  process.  The  concentration  of  both 
copper  and  zinc  ores  in  the  United  States  as  in  other  parts  of  the 
world  is  now  effected  by  agitating  the  finely  pulverized  ore  with 
water  in  the  presence  of  a  small  quantity  of  oil.  White  fatty  oils, 
mineral  oils,  coal-tar  and  wood-tar  creosotes  have  been  used,  certain 
essential  oils  have  been  found  to  be  specially  adapted  for  this  treat- 
ment. In  this  country  pine  oils,  both  steam  distilled  and  destruc- 
tively distilled  have  been  especially  used  and  quite  an  industry  in 
these  oils  has  developed.  The  magnitude  of  our  copper  and  zinc 
production  is  such  that  although  the  amount  of  oil  used  in  this  flota- 
tion process  is  relatively  small  (less  than  1  per  cent,  on  the  ore),  the 
aggregate  consumption  of  oil  is  very  large. 
The  war  demand  has  greatly  increased  the  call  for  rubber  goods 
of  all  kinds,  especially  automobile  tires,  and  consequently  the  con- 
sumption of  crude  rubber  has  grown  rapidly.  The  importations  of 
rubber  in  1914  amounted  to  132  million  lbs.,  but  grew  to  390  mil- 
lion lbs.  in  1918.  The  exports  of  rubber  boots  and  shoes  amounted 
to  $1,113,495  for  1914  and  to  $5,774,341  in  1918;  the  automobile 
tire  exports  were  valued  at  $4,068,639  in  1914  and  at  $15,128,294 
in  1918. 
In  this  connection  reference  may  be  made  to  the  greatly  increased 
demand  for  organic  solvents  and  the  work  done  to  meet  this  demand. 
The  most  important  work  of  this  kind  is  probably  the  production  of 
acetone  and  similar  solvents  from  the  Pacific  Coast  kelp  by  the  Her- 
cules Powder  Co.,  and  this  fortunately  we  will  have  specially  pre- 
sented at  this  time  in  a  paper  dealing  fully  with  the  subject. 
Another  promising  line  is  the  manufacture  of  amyl  acetate  from 
petroleum  pentane  recently  described  in  the  Journal  of  Ind.  and 
Eng.  Chemistry  for  July,  191 8.  This  work  has  been  carried  out  at 
the  Mellon  Institute  in  Pittsburgh,  Pa.  The  use  of  these  organic 
solvents  is  manifold,  but  we  may  note  the  extensive  use  of  pyroxy- 
line  solvents  and  the  greatly  increased  use  of  lacquers  of  this  de- 
scription in  the  last  four  years.  From  aeroplane-wing  dope  to 
artificial  leather  we  have  a  variety  of  utilizations  and  some  of  these 
have  grown  to  extensive  industries  within  the  past  few  years. 
Closely  allied  to  this  industry,  is  the  artificial  silk  industry,  one 
