I 
I 
^""fI^'is^l'""}  Chemical  Notes.  59" 
point  of  water.  Other  substances  exhibit  these  same  phenomena,  the 
next  notable  of  which  is  mercuric  chloride,  for  which  latter  the  pres- 
sure need  only  be  reduced  to  about  4*20  mm.  On  letting  in  the  pres- 
sure the  substance  at  once  liquefies. — Chem.  News,  vol.  42,  p.  130. 
Preparation  of  HydrochloriG  Acid. — When  it  is  desired  to  have  a 
regulated  stream  of  hydrochloric  acid  gas  for  any  purpose,  it  can  be 
readily  gotten,  according  to  L.  de  Koninck,  by  the  action  of  sulpliuric 
acid  upon  ammonium  chloride,  reference  being  also  had  in  the  con- 
struction of  the  apparatus  to  the  fact  that  a  solution  of  ammonium  sul- 
phate in  sulphuric  acid  is  lighter  than  sulphuric  acid  itself. — Ber.  der 
Chem.  Ges.,  xiii,  p.  2240. 
Method  for  the  Quantitative  Determination  of  Nitric  Acid, — O.  von 
Dumreicher  has  found  that  nitric  acid  is  converted  by  acid  stannous 
chloride  solution  into  ammonia  without  any  evolution  of  gas.  To 
apply  this  fact  to  the  determination  of  nitric  acid  the  substance  contain- 
ing the  nitric  acid  is  boiled  for  an  hour  with  a  large  excess  of  acid 
stannous  chloride  solution  (16  parts  of  tin  dissolved  in  60  parts  of  40 
per  cent,  hydrochloric  acid)  and  then  evaporated  over  the  water-bath 
until  a  crystalline  scum  begins  to  form.  In  this  residue  of  evapora- 
tion the  ammonia  can  be  determined  in  the  usual  way. — Ibid.,  p.  2241. 
Potassium  and  Sodium  Aluminates. — A.  B.  Prescott  has  found  that 
when  a  solution  of  potassium  alum  is  treated  with  caustic  potash  solu- 
tion until  the  precipitate  formed  was  just  dissolved,  no  matter  what 
the  concentration  of  the  solution  was,  the  proportion  of  potassium  to- 
aluminum  in  the  soluble  aluminate  is  represented  by  the  formula 
KgAlaO^  or  Al202(OK)2,  the  equation  being : 
K2  Al2(S0,), + (KOH)8=K2  AI2O,  H-  4K2SO4 + 4H2O. 
The  same  compound  is  obtained  by  saturating  caustic  potash  with 
aluminum  hydrate,  evaporating  to  dryness  and  extracting  the  excess  of" 
alkali  with  alcohol.  The  same  results  were  also  obtained  with  sodium 
aluminate. 
Prescott  finds,  moreover,  that  the  zinc-alkali  compound  has  the 
composition  K2Zn02  or  Zn(OK)2  or,  for  the  soda  compound,  iS^a2ZnOo«. 
—  Chem.  News,  vol.  42,  pp.  29  and  30. 
Organic  Chemistry. — On  Saccharin  and  Saccharic  Acid. — Scheib- 
ler  has  investigated  the  saccharin  discovered  by  Peligot,  and  obtained 
by  him  from  the  mixture  of  dextrose  and  levulose,  called  invert  sugar. 
Peligot  gives  it  the  composition  C12H22O11  because  it  has  the  same  per- 
centage composition  as  cane  sugar  (saccharose).    Scheibler  finds  that 
