258  Gleanings  from  the  Foreign  Journals.  { AmMJa0yu>r-l8p7h8"m- 
over  88  per  cent  of  fatty  acids.  The  determination  is  made  by  fusing  the  butter 
and  freeing  it  completely  from  water,  salt  and  casein  5  about  4  grms.  of  it  are  then 
completely  saponified  by  alkali  in  the  presence  of  alcohol,  the  solution  of  soap  is 
concentrated,  the  residue  taken  up  in  about  150  grms.  of  water,  decomposed  by 
muriatic  acid  and  the  fatty  acid  washed,  dried  and  weighed. — Zeitschr.  Anal.  Chem., 
xvi,  145. 
Husson  dissolves  the  butter  in  10  times  its  weight  of  a  mixture  of  equal  parts  of 
90  per  cent,  alcohol  and  ether  at  a  temperature  of  35  to  4o°C.  (95  to  io4°F.).  The 
solution  is  set  aside  for  24  hours  at  a  temperature  of  about  i8QC.  (64'4QF.)  and  the 
separated  solid  fat,  of  which  pure  butter  yields  not  over  40  and  not  less  than  35  per 
cent  ,  is  collected  and  weighed.  If  more  than  40  per  cent.,  the  butter  is  adulterated 
with  tallow  or  suet;  if  less  than  35  per  cent.,  lard,  goose  grease  or  similar  fats  are 
present. — Jour,  de  Phar.  et  de  Chim.,  Sept.,  1877,  p.  100. 
Preparation  of  Indigo  Carmine. —  V.  Joclet  gives  the  following  process :  1  kilo 
of  powdered  good  Bengal  indigo  is  gradually  added  to  5  kilos  of  strong  sulphuric 
acid,  heated  in  a  water-bath  to  45  to  5o°C.  (113  or  i22°F.)  When  dissolved, 
the  liquid  is  poured  into  a  suitable  vessel,  and  for  every  kilo  there  is  slowly 
added  a  solution  of  3k.  of  clear  crystallized  sal  soda?  dissolved  in  30k.  of  watpr. 
The  mixture  is  occasionally  stirred  during  12  hours  to  facilitate  the  extrication  of 
the  carbonic  acid  gas,  set  aside  for  some  time,  and  then  passed  through  a  woolen 
filter,  the  filtrate  being  collected.  The  contents  of  the  filter  are  transferred  to  a 
vessel  with  an  inner  perforated  bottom,  upon  which  a  woolen  strainer  is  placed,  and 
more  indigo  carmine  solution  obtained  and  withdrawn  by  means  of  a  stopcock. 
Finally  indigo  purple  remains  upon  the  filter. — Chem.  Cent.  BL,  No.  10,  D.  Fdrber- 
Z,  1877. 
Preparation  of  Phosphorous  Acid. — I.  Corne  recommends  to  partly  immerse 
phosphorus  in  distilled  water,  and  after  several  days'  exposure  precipitate  the  phos- 
phoric acid  from  the  liquid  by  the  addition  of  ammonia,  ammonium  chloride  and 
magnesium  sulphate.  The  filtrate  is  heated  to  expel  excess  of  ammonia,  and  then 
mixed  with  acetate  of  lead,  whereby  sulphate,  chloride  and  phosphite  of  lead  are 
precipitated.  The  precipitate  is  well  washed  and,  at  a  moderate  heat,  digested  with 
ammonium  acetate,  whereby  the  two  former  salts  are  dissolved,  while  the  lead 
phosphite  remains  behind,  and  after  washing  is  decomposed  by  sulphuretted  hydro- 
gen. The  solution  is  filtered,  heated  to  expel  H2S,  and  now  contains  pure  phos- 
phorous acid. — Jour,  de  Phar.  et  de  Chim.,  Feb.,  1878,  p.  100. 
Persulphuric  acid,  S207,  is  a  new  acid,  which  has  been  obtained  under  the  influ- 
ence of  electricity  upon  a  mixture  of  dry  sulphurous  acid  gas  and  oxygen  5  it  crys- 
tallizes at  a  low  temperature  in  transparent  needles.  It  may  also  be  obtained  in  the 
form  of  solution  by  carefully  mixing  chlorine  water  with  concentrated  sulphuric 
acid,  but  is  not  formed  if  the  latter  contains  more  than  2  equiv.  of  water.  Under 
various  conditions  the  new  acid  may  be  obtained  from  concentrated  sulphuric  acid, 
perhaps  also  by  acting  with  the  latter  upon  alkaline  or  metallic  peroxides  in  the 
cold. — Ibid.,  March,  168. 
