42 
EXTRACTION  OF  THALLIUM. 
caustic  ley,  a  liquid,  volatile  and  inflammable  alkaloid  was  ob- 
tained, whilst  sulphur  and  phosphorus  remained  combined  with 
the  alkali,  and  were  easily  detected.  The  author  is  satisfied,  from 
twelve  months'  research,  that  no  sulphuretted  or  phosphoretted 
hydrogen  was  given  off,  and  his  researches  tend  to  prove  that  the 
noxious  vapors  given  off  during  putrefaction  contain  the  nitrogen, 
sulphur,  and  phosphorus  of  the  animal  substance,  and  that  these 
elements  are  not  liberated  in  the  simple  form  of  ammonia,  and 
sulphuretted  and  phosphoretted  hydrogen.  As  putrefaction  pro- 
ceeds, different  volatile  bodies  are  given  off.  The  platinum  salts, 
heated  in  test  tubes,  give  off  vapors,  some  acid,  some  alkaline,  of 
a  most  noxious  and  sickening  odor,  resembling  putrefaction, 
while  a  white  crystalline  sublimate  is  formed,  which  is  not  sal- 
ammoniac.  These  researches  are  still  in  progress,  and  will  occupy 
several  years. — Am.  Journ.  Science  and  Arts,  Nov.,  1863. 
ON  THE  EXTRACTION  OF  THALLIUM  ON  A  LARGE  SCALE 
FROM  THE  FLUE  DUST  OF  PYRITES  BURNERS. 
By  W.  Crookes,  F.  R.  S.* 
All  the  processes  for  the  extraction  of  thallium  hitherto  pub- 
lished by  myself  and  others  have  been  applicable  to  but  small 
quantities  of  the  material  from  which  the  metal  is  obtained. 
They  have  in  most  cases  directed  the  employment  of  distilled 
water  and  porcelain  basins,  and  have  involved  the  passing  of 
sulphuretted  hydrogen  through  filtrates — a  method  of  proceed- 
ing altogether  out  of  the  quescion  when  large  quantities  of  de- 
posit are  to  be  dealt  with.     Having  for  many  months  past  been 
occupied,  in  conjunction  with  Messrs.  Hopkin  and  Williams, 
manufacturing  chemists,  of  Wandsworth,  on  the  extractum  of 
.the  metal   from  an  amount   of  material   far  greater  than 
has  ever  been  treated  before,  I  propose  to  bring  before  the  meet- 
ing an  account  of  the  methods  we  have  ultimately  adopted. 
I  have  received  from  various  quarters  some  hundreds  of  speci- 
mens of  deposit,  flue  dust  and  minerals,  every  one  of  which 
was  first  of  all  carefully  tested  for  thallium  by  means  of  the 
spectroscope.    The  practical  employment  of  spectrum  analysis 
*Read  before  the  British  Association  at  Newcastle-upon-Tyne,  Sep  - 
tember  1,  1863. 
