-Am.  Jour.  Pham..\ 
.November,  1895.  j 
Australian  Myrtaceous  Kinos. 
377 
extinguish  parallel  to  the  principal  axis  and  polarize  at  times  in 
bright  colors.  They  show  faces  of  the  right  rhombic  prism  with 
brachypinakoids.  The  termination  planes  are  mostly  macrodomes, 
pyramidal  faces  not  having  yet  been  detected.  The  formula,  there- 
fore, is : 
(00    P  -f  00    P  00    +  P  50  ). 
The  eudesmin  crystallized  from  absolute  alcohol  was  found  to  be 
anhydrous.  When  it  is  dissolved  in  hot  alcohol,  water  added  until 
the  slightest  precipitate  appears  to  form,  and  the  solution  left  to 
stand  for  some  hours,  beautiful  acicular  crystals  are  obtained,  in 
some  cases,  of  nearly  half  an  inch  in  length. 
Eudesmin  is  soluble  in  hot  water,  but  crystallizes  out  again  on 
cooling.  It  melts  on  the  surface  of  mercury  at  990  C.  into  a  whitish 
resinous-looking  mass,  partly  transparent ;  and  on  this  account, 
care  must  be  taken  not  to  raise  the  temperature  too  rapidly  or  too 
high  when  determining  its  solubility  in  water,  as  it  fuses  into  a 
globular  mass.  It  is  also  soluble  in  ether,  acetic  ether  and  chloro- 
form, but  not  in  benzol,  petroleum  spirit  or  bisulphide  of  carbon. 
Its  solutions  in  water  and  alcohol  are  neutral  in  reaction. 
Aqueous  or  alcoholic  potash  solutions  exert  but  slight  solvent 
action  on  eudesmin,  either  in  the  cold  or  on  warming.  Glacial  acetic 
acid  dissolves  it,  and  the  addition  of  water  causes  it  to  sepa- 
rate. 
Eudesmin  is  odorless  and  almost  tasteless,  being  very  slightly 
sweetish.  When  ignited  it  readily  burns  with  a  very  smoky  flame. 
Concentrated  sulphuric  acid  dissolves  eudesmin  with  the  production 
of  a  dark  color,  which  changes  to  purple ;  after  standing  some  time 
or  when  water  is  added,  this  color  fades  and  a  dark  precipitate  sepa- 
rates. Eudesmin  is  soluble  in  strong  nitric  acid  with  a  beautiful 
yellow  color ;  after  a  time  dendritic  forms  of  a  light  yellow  color 
make  their  appearance,  and  continue  to  increase  until  the  alteration 
is  completed.  These  reactions  with  sulphuric  and  nitric  acids 
appear  to  be  characteristic. 
Fuming  nitric  acid  behaves  like  strong  nitric  acid,  except  that  it 
dissolves  the  eudesmin  with  explosive  violence.  It  is  to  these  alter- 
ation and  decomposition  products  that  we  must  eventually  look  to 
determine  the  molecular  constitution  of  eudesmin. 
To  ascertain  the  chemical  composition,  two  combustions  were 
