Am6cSerj9hi4rm'}       Identification  of  Artificial  Silks.  473 
No.  I.    Glycerinated  Sulphuric  Acid. 
Pure  Glycerin    10  c.c. 
Distilled  Water   5  c.c. 
Add  slowly  with  constant  stirring,  a  few  drops  at 
a  time,  Pure  Concentrated  Sulphuric  Acid   15  c.c. 
No.  2.   Iodo-iodide  of  Potassium. 
Distilled  Water   30  c.c. 
Potassium  Iodide    0.3  gr. 
Iodine,  an  excess. 
No.  3.    Chlor-iodide  of  Zinc. 
Distilled  Water   30  c.c. 
Fused  Chloride  of  Zinc  .  ..  1.75  gr. 
Filter  and  add  to  clear  nitrate  Iodine  to  saturation. 
No.  4.    Cold  Concentrated  Sulphuric  Acid. 
No.  5.  Half  Saturated  Chromic  Acid. 
No.  6.  A  40  per  cent.  Caustic  Potash  Solution. 
No.  7.  Copper-Oxide-Ammonia. 
This  is  an  important  reagent  in  all  fibre  work.   It  should  be  made 
with  great  care  by  preparing  a  solution  of  copper  oxide  in  ammonia  to 
saturation,  and  passing  through  it  a  current  of  air  freed  from  carbon 
dioxide,  by  first  being  passed  through  a  solution  of  caustic  potash. 
No.  8.    Nickel  Oxide  Ammonia. 
Nickel  Sulphate  in  crystals   2  gr. 
Water   30  c.c. 
Precipitate  the  nickel  with  caustic  soda  and  filter;  then  dissolve 
the  precipitate  in  a  mixture  of : 
Concentrated  Ammonia    8  c.c. 
Water    8  c.c. 
No.  9.    Alkaline  Copper  Glycerin  Solution. 
Sulphate  of  Copper   3  gr. 
Water    30  c.c. 
Glycerin    1 .75  gr. 
to  which  is  added  a  sufficient  quantity  of  caustic  potash  solution  to 
precipitate  the  copper  and  redissolve  it. 
No.  10.    Diphenylamine-Sulphuric  Acid  Solution. 
Diphenylamine   1.57  gr. 
Concentrated  Sulphuric  Acid    25  c.c. 
The  operator  should  keep  these  bottles  in  a  closet  when  not  in 
use  and  at  all  times  free  from  dust.  The  label,  besides  the  name, 
should  also  have  the  formula  written  upon  it. 
