AmMJa°rch,  St.™' }    The  A pocynacece  in  Materia  Medica.  1 5  7 
All  attempts  to  combine  argon  with  other  elements  failed.  It 
was  found  to  be  a  monatomic  gas  and,  as  a  monatomic  gas  can  be 
only  an  element  or  a  mixture  of  elements,  it  follows  that  argon  is 
not  of  a  compound  nature. 
From  Avogadro's  law  the  density  of  a  gas  is  half  its  molecular 
weight ;  and,  as  the  density  of  argon  is  approximately  20,  hence  its 
molecular  weight  must  be  40.  But  its  molecule  is  identical  with  its 
atom ;  hence  its  atomic  weight  or,  if  it  be  a  mixture,  the  mean  of 
the  atomic  weights  of  that  mixture,  taken  for  the  proportion  in 
which  they  are  present,  must  be  40.  It  was  decided  to  assign  to 
argon  the  symbol  A. 
In  addition  to  the  foregoing  information,  Dr.  William  Crookes 
read  a  paper  On  the  Spectra  of  Argon,  and  Dr.  K.  Olszewski  con- 
tributed the  results  of  his  experiments  on  The  Liquefaction  and 
Solidification  of  Argon.  Two  sealed  tubes  of  the  new  element  were 
exhibited  at  the  meeting  and  Lord  Kelvin,  who  presided,  Dr.  Arm- 
strong and  Professor  Rucker,  all  expressed  themselves  as  believing 
that  a  new  element  of  the  atmosphere  lias  been  discovered.  We 
are  indebted  to  the  Chemical  News,  of  February  1st,  for  the  above 
information. 
THE  APOCYNACEyE  IN  MATERIA  MEDICA. - 
By  George  m.  Beringer. 
{Continued  from  page  104.  Conclusion). 
O.  Henry  and  Ollivier,  in  1824,  first  obtained  from  Tanghin  a 
fixed  oil,  a  crystalline  substance,  very  poisonous,  and  a  varnish-like 
substance  which  they  named  Tanguine.  J.  Chatin  obtained  the  crys- 
tals in  prisms,  of  which  the  nature  was  not  determined.  In  1889 
Arnaud  isolated  the  active  principle,  Tanghinine ,  in  crystals,  and 
presenting  the  singular  property  of  swelling  up  with  water.  It  is 
present  in  the  kernels  to  the  extent  of  1  per  cent.  It  is  neither  an 
alkaloid  nor  a  glucoside.  Arnaud  states  that  the  seeds  contain  an 
abundant  amount  of  oil,  which  cannot  be  obtained  by  simple  expres- 
sion, as  an  emulsion  is  formed  with  the  water.  He  recommends 
the  extraction  with  carbon  disulphide.  J.  Chatin  concludes,  from 
his  experiments  with  this  oil,  that  it  is  absolutely  inoffensive. 
Quinquaud  observes  the  great  excitability  of  the  medulla  by  the 
