90  Analytical  Researches  and  Investigations.  {^"^J^^i^^g^^"'' 
The  first  gave  70*5  per  cent.,  the  second  70  per  cent  of  potassium 
iodide. 
17,5  .  100 
From  the  formula  X  =  ,  in  which  n  represents  the  degree 
of  concentration  of  tlie  alcoiiol  to  be  standardized,  the  volume  of  alco- 
hol may  be  calculated  with  sufficient  accuracy  which  is  required  to  be 
added  to  the  water,  in  order  to  obtain  100  parts  of  17*5  per  cent, 
alcohol. — Ibid,  p.  1425,  from  Rep.  Fharm.,  38,  p.  443. 
A  Delicate  Test-paper  for  Gaseous  Ammonia. — Kroupa  dissolves  fuch- 
sine  in  water,  and  adds  to  the  sokition  dilute  sulphuric  acid,  whereby 
it  becomes  of  a  yellowish-brown  color  ;  the  solution  is  then  highly 
diluted  and  strips  of  unsized  paper  moistened  therewith,  which  are 
afterward  dried.  This  test-paper,  which  is  of  a  beautiful  yellow  color, 
is  applied  in  the  dry  state,  and  is  capable  of  detecting  an  amount  of 
ammonia  corresponding  to  0*0005  gram  of  ammonium  chloride;  the 
yellow  color  becoming  changed  to  a  beautiful  carmine-red. — Pharm. 
Zeitsclir.  fur  Russ.,  Xo.  50,  1882,  from  Zeitschr.  fur  Analyt.  Chem.j, 
xxi.,  p.  391. 
tlydrocinclioiddiiie. — According  to  O.  Hesse  this  alkaloid  is  fre- 
quently contained  in  commercial  cinchonidine  and  homocinchonidine 
preparations,  especially  in  the  respective  sulphates,  when  they  do  not 
form  loose  crystalline  needles.  In  order  to  prepare  hydrocinchonidine 
therefrom  it  is  only  necessary  to  convert  them  in  the  usual  way  into 
hydrochlorates,  and  to  allow  these  to  crystallize  from  water.  The 
hydrochlorate  of  hydrocinchonidine  thereby  remains  in  the  mother  liquid^ 
is  obtained  by  evaporation,  and  finally  obtained  therefrom  in  a  pure 
condition.  It  crystallizes  from  hot  dilute  alcohol  in  beautiful  six-sided 
laniin^se,  and  from  strong  alcohol  in  short  prisms. 
Hydrocinchoyudine  has  the  formula  CigHg^NgO,  and  therefoi  e  bears 
the  same  relation  to  cinchonidine  as  hydroquinine  to  quinine;  it  melts 
at  229-230°C.,  and  does  not  show  in  the  acid  sulphuric,  acetic,  and 
nitric  acid  solution,  even  when  highly  diluted,  the  slightest  blue  fluor- 
escen(;e,  nor  does  it  give  with  chlorine  and  an  excess  of  ammonia  any 
coloration. 
Hydrochlorate  of  Hydrocinchonidine,  CigHg^NgO,  HCI-I-2H2O,  forms 
short,  six-sided  prisms,  which  are  readily  soluble  in  water  and  in  alco- 
hol. If  the  neutral  salt  be  dissolved  in  very  strong  hydrochloric  acid, 
the  acid  salt  crystallizes  in  colorless  tables. 
