ON  THE  NEW  METAL  THALLIUM. 
403 
These  researches,  in  which  I  have  been  greatly  aided  by  M. 
Ubaldini,  will  be  pursued  for  the  3tudy  of  the  neutral  and  acid 
matters  contained  in  modified  pyroxylin. — Journ.  de  Pharm., 
Juin,1862. 
ON  THE  NEW  METAL  THALLIUM. 
By  M.  A.  Lamy. 
On  examining,  three  months  ago,  with  MM.  Kirchhoff  and 
Bunsen's  spectrum  apparatus,  a  specimen  of  selenium  prepared 
by  my  brother-in-law,  M.  Fred.  Kuhlmann,  from  the  deposits 
in  the  chambers  in  which  sulphuric  acid  was  made  by  the  com- 
bustion of  pyrites,  I  perceived  a  sharply-defined  green  line  which 
I  had  not  observed  in  any  of  the  numerous  simple  bodies  or 
mineral  compounds  which  I  had  studied.  I  was  not  then  aware 
that  an  English  chemist,  Mr.  W,  Crookes,*  had  not  only  dis- 
covered the  same  green  line  under  almost  analogous  circum- 
stances, but  had  given  the  name  of  thallium  to  the  new  element, 
from  the  Greek  word  8*x^?,  or  Latin  thallus,  frequently  employ- 
ed to  express  the  rich  tint  of  young  and  vigorous  vegetation. 
Mr.  Crookes,  with  great  skill,  described  several  of  the  reactions 
of  the  element,  which  he  considered  as  a  metalloid,  probably 
belonging  to  the  sulphur  group  ;  but  the  small  quantity  of  sub- 
stance did  not  permit  him  to  isolate  this  element  and  recognise 
its  true  nature. 
We  have  endeavored  to  isolate  the  new  body  by  seeking  for 
it  in  the  deposits  from  the  leaden  chambers  whence  the  selenium 
had  been  extracted,  which  gave  us  in  the  spectroscope  the 
characteristic  green  line.  This  line  has  naturally  served  us  as 
a  guide,  and  has  enabled  us  to  prepare  perfectly  definite  crystal- 
line compounds,  whence  we  have  extracted  thallium, — the  first 
time  with  the  assistance  of  an  electric  battery. 
Properties  of  Thallium  Thallium  has  all  the  characters  of  a 
true  metal,  and,  in  most  of  its  physical  properties,  greatly  re- 
sembles lead.  Not  quite  so  white  as  silver,  it  possesses  a  bril- 
liant metallic  lustre  when  freshly  cut.  It  appears  yellowish 
when  rubbed  against  a  hard  body  ;  but  this  tint  is  doubtless  due 
*  Mr,  Crookes  obtained  the  element  in  a  pure  metallic  state,  investigated 
its  properties  and  exhibited  it  to  several  friends  as  early  as  January  last, 
(see  paper  read  before  Royal  Society,  June  19,  1862.) 
