552 
Technical  Chemistry. 
f  Am.  Jour.  Pharm. 
I  November,  1900. 
with  internal  firing  for  making  charcoal,  and  greater  economy  is 
being  attained  in  acetate  production. 
In  the  way  of  rubber  products,  the  new  substitute,  Reid's  "  vel- 
vril,"  is  claimed  to  have  had  a  successful  year's  trial  in  England, 
and  to  have  gained  a  large  use.  Velvril  is  a  drying  oil  which  has 
been  nitrated,  mixed  by  a  common  solvent  with  nitrocellulose,  and 
the  solvent  subsequently  removed.  Castor  oil  is  said  to  be  used, 
and,  after  nitration,  contains  4-5  per  cent,  of  nitrogen.  This,  with 
nitrocellulose,  forms  a  clear,  homogeneous,  rubber-like  mass,  its 
hardness  being  wholly  under  control  by  varying  the  relative  propor- 
tions of  the  two  ingredients,  from  a  consistency  like  vulcanite  to 
that  of  the  softest  rubber.  The  article  to  be  made  may  be  shaped 
from  the  mixture  while  softened  by  a  solvent,  or  formed  into  shape 
by  high  pressure  and  heat  somewhat  above  1 00°  C.  In  spite  of  its 
nitrated  character  it  is  not  explosive,  but  burns  slowly  and  quietly. 
Numerous  uses  are  claimed  for  the  new  compound  by  its  inventors, 
including  insulating  material,  clothing,  belting,  varnish,  paint,  en- 
amelling of  leather,  cement  for  wood,  glass,  metal,  etc.,  hose  and 
tubing,  and  even  as  a  modifier  of  the  explosive  rate  and  power  of 
guncotton  and  nitroglycerin.  If  only  a  small  proportion  of  these 
claims  stand  the  test  of  continued  use,  a  most  valuable  discovery 
has  been  made,  and  a  substance  of  the  widest  applicability  and  use 
found  at  an  exceedingly  opportune  time,  because  of  the  enormously 
increased  demand  for  rubber  in  so  many  industries. 
Not  even  a  few  of  the  inventions  and  processes  described  above 
were  actually  begun  or  perfected  during  1899,  but  all  for  the  first 
time  last  year  stood  the  test  of  continued  practical  use.  Inventions 
almost  without  number  are  recorded  every  year,  but  it  would  take  an 
omnipotent  judge  to  select  those  that  are  destined  to  work  industrial 
revolutions,  and  their  description  or  bare  enumeration  would  be 
of  little  interest  and  less  value  here.  The  record  given  has,  there- 
fore, been  confined  to  those  inventions  and  changes  which  the  year 
has  recorded  as  of  permanent  value,  and  which  have  proved  them- 
selves commercially  successful. 
Saucyuc  Acid  in  Presence  of  Citric  Acid  may  be  determined,  accord- 
ing to  Jorissen,  as  follows  :  10  c.c.  of  the  liquid  are  mixed  with  four  drops  of  a 
solution  (10  per  cent.)  of  potassium  or  sodium  nitrite,  four  drops  of  acetic  acid 
and  one  drop  of  a  solution  (10  per  cent.)  of  copper  sulphate.  The  mixture  is 
heated  to  the  boiling  point,  and  if  salicylic  acid  is  present  a  blood  red  color  is 
produced. 
