Liquefaction  of  Gases.  185 
sulpho-molybdic  acid,  remains  unchanged  after  24  hours.  Its  compo- 
sition is  C19H24N202-}-H20. 
The  bark  contains  also  a  greyish-white  amorphous  alkaloid,  which 
is  readily  soluble  in  ether,  colors  nitric  acid  blood-red  and  pure 
sulphuric^acid  violet-red  ;  the  name  pereirina  is  proposed  for  it. — Ber. 
d.  Chem.  Ges.,  1877,  p.  2163. 
Am.  Jour.  Pharm. ) 
April,  1878.  j 
LIQUEFACTION  OF  GASES. 
Almost  simultaneously,  and  entirely  independent  of  each  other,  the 
liquefaction  of  oxygen  was  accomplished  in  December,  1877,  by  L. 
Cailletet  of  Paris  and  Raoul  Pictet  of  Geneva.  Cailletet's  letter  to 
the  Academy  of  Sciences  announcing  his  discovery  was  dated  Decem- 
ber 2,  sealed  by  the  permanent  secretary  on  the  following  day,  and  read 
before  the  Academy  December  24,  when  Mr.  Dumas  announced  that 
o 
Fig.  1. 
the  same  result  had  been  accomplished  by  Pictet  December  22,  of 
which  he  had  been  informed  by  telegraph.  „ 
