312  Abstracts  from  the  French  Journals.  {AmjuXi22arm' 
and  found  in  the  residue  bichloride  of  mercury,  and  in  the  distillate 
hydrocyanic  acid.  To  arrive  at  some  conclusion  as  to  the  cause  of 
the  acidity  of  the  mixture  the  author  used  tropeolin.  This  sub- 
stance is  not  acted  on  by  either  alone,  but  on  mixing,  a  violet  red 
color  appears,  showing  the  presence  of  some  free  stronger  acid 
(hydrochloric  acid).  To  obtain  the  other  body  formed  in  the  reac- 
tion, the  author  added  silver  carbonate  when  carbonic  acid  (mis- 
print in  loc.  cit.,  reads  hydrochloric  acid)  was  eliminated;  after  filtra- 
tion, evaporation  and  crystallization  cyanide  of  mercury,  with  a 
trace  of  cyanide  of  silver  was  obtained. 
Boric  Acid. — P.  Carles  {Rep.  de  Pharm.,  1892,  102)  found  two 
kinds  of  boric  acid  in  the  pharmacies  of  France,  the  one  in  flakes, 
which  is  generally  known,  and  the  second  a  prismatic  variety  which 
differs  markedly  from  the  first.  The  ordinary  kind  forms  pearly 
flakes  or  hexagonal  plates,  is  light,  and  is  unctuous  to  the  touch 
while  the  other  variety  is  in  prisms,  heavy  and  does  not  possess  the 
unctuous  touch.  The  author  found  that  (1)  the  solubility  in  strong 
alcohol  is  the  same  with  both  varieties;  (2)  the  insoluble  portion, 
about  1  per  cent.,  is  principally  sulphates  in  the  flakes,  and  chlorides 
in  the  prismatic  acid  ;  (3)  there  is  usually  a  larger  proportion  of  an 
empyreumatic  organic  body  in  the  prismatic  variety  than  in  the 
other ;  (4)  both  varieties  when  purified  crystallize  in  plates.  The 
author  prepared  some  of  the  boric  acid  from  borax,  using  in  the 
one  case  sulphuric,  and  in  the  other  hydrochloric  acid.  In  the 
first  case  the  boric  acid  crystallizes  on  the  surface  in  plates,  while  in 
the  second  it  crystallizes  in  the  bottom  of  the  receptacle.  If  the 
flaky  acid  be  crystallized  from  a  solution  containing  a  chloride  or 
hydrochloric  acid  it  will  separate  in  the  form  of  prisms.  The  crys- 
tals in  this  case  are  separate,  and  as  they  can  be  obtained  quite 
small  in  size  the  purification  is  not  so  difficult,  since  they  cannot 
have  much  of  the  mother  liquor  adhering  after  the  first  washing. 
Another  point  in  which  these  varieties  differ  is  in  the  readiness  with 
which  they  are  reduced  to  ponder,  the  prismatic  variety  powdering 
very  easily. 
Strontium  Chloride. — According  to  A.  Etard  {Compt.  rend., 
cxiii,  856)  the  aqueous  solution  deposits  below  400  C.  needles 
of  SrCl2,  6H20.  Between  900  and  1300  C.  'amellae  of  SrCl2, 
2H20  are  formed,  and  at  75 0  both  needles  and  lamellae  are 
deposited.    Heated  to  145 3,  the  saturated  solution  deposits  at  first 
