VARIETIES. 
377 
Method  for  assaying  the  purity  of  Arrow  Root  from  the  Maranta. — 
M.  Albers  (Archiv.  der  Pharm.  and  Dingler's  Polytech.  Jour.,)  gives  the 
following  method  for  discovering  the  presence  of  wheat  or  potato  starch 
in  the  arrow-root  of  the  Maranta.    The  following  is  the  process  : 
Take  one  part  of  fecula,  and  mix  it  with  three  parts  of  a  proof  liquor, 
consisting  of  two  parts  of  chlorohydric  acid,sp.  gr.  1*120,  and  one  part  of 
water,  at  the  ordinary  temperature.  In  three  or  four  minutes  pure  arrow- 
root will  not  be  affected  by  the  acid  liqaor,  but  wheat  or  potato  starch, 
on  the  contrary,  will  be  changed  to  a  transparent  gelatinous  mass,  which 
becomes  fluid  by  the  further  action  of  the  acid,  transforming  the  starch 
jelly  to  dextrine.  When  potato  starch  is  the  adulterant,  it  evolves  a 
peculiar  odor,  well  known  to  those  who  have  made  dextrine  from  it. 
"When  a  mixture  thus  exists,  the  true  arrow-root  granules  will  subside  as 
the  gelatinized  adulterant  is  converted  to  dextrine,  and  may  be  separated 
by  a  strainer,  washed,  dried  and  weighed,  and  the  relative  amount  of 
adulteration  may  be  judged  of  approximately  by  the  consistence  of  the 
jelly  as  at  first  developed. — Jour,  de  Pharm.,  218  Fevrier,  1866. 
Urea  a  normal  constituent  of  Coios'  Milk. — M.  Lefort  announces  {Jour, 
de  Pharm.,  March,  1866,  p.  177,)  the  existence  of  urea  in  the  milk  of 
healthy  cows.  From  10  litres  (2£  gallons)  of  this  milk  he  obtained  23. 
grains  of  nitrate  of  urea,  easily  characterized  by  its  crystals  and  by  its 
combination  with  binoxide  of  mercury. 
Alloys  of  Manganese. — In  Germany  M.  E.  Priegerhas  commercially  pre- 
pared alloys  of  manganese  with  iron  or  copper  possessing  valuable  proper- 
ties, and  the  application  of  which  are  constantly  improving  in  number  and 
utility.  To  prepare  the  alloys  of  iron  and  manganese  (ferro  manganese^, 
he  made  a  mixture  of  pulverized  oxide  of  manganese,  charcoal  dust  (cor- 
responding in  quantity  to  the  oxygen  of  the  oxide)  and  of  metallic  iron 
sufficiently  broken  up,  such  as  minute  grains  of  cast-iron  filings  or  turn- 
ings of  iron  or  steel,  &c.  ;  the  mixture  was  put  into  a  graphite  crucible, 
which  would  hold  from  15  to  25  kilogr.,  and  covered  with  a  coating  of 
charcoal  dust,  sea  salt,  &c,  then  heated  for  a  few  hours  at  a  white  heat. 
After  cooling  there  was  at  the  bottom  of  the  crucible  a  metallic  homoge- 
nous mass,  containing  but  very  insignificant  quantities  of  foreign  bodies. 
Of  these  alloys  the  most  important  are  those  containing  2  equivalents  of 
manganese  to  1  of  iron,  and  4  equivalents  of  manganese  to  1  of  iron,  and 
corresponding  to  66-3  per  cent.,  and  79*7  per  cent,  of  manganese.  Both 
are  harder  than  tempered  steel;  they  are  capable  of  receiving  a  very  high 
polish,  they  melt  at  red  heat,  and  can  be  easily  poured  ;  they  do  not  oxi- 
dize in  the  air,  and  even  in  water  only  superficially  ;  their  white  color  is 
of  a  shade  between  steel  and  silver.  Alloys  of  copper  and  manganese  are 
similarly  obtained;  they  resemble  bronze,  but  are  much  harder  and  more 
durable.    Alloys  of  tin  are  very  fusible,  durable,  and  easy  to  work  ;  in 
