1 6  Selections  from  the  Foreign  Journals.  {AmjJanU,rxl>77arm' 
sulphuretted  hydrogen  as  trisulphide  of  arsenic,  As2S3,  and  weighed  on 
a  tared  filter. 
20  cc,  heated  with  sulphuric  acid,  H2S04,  and  then  introduced  in 
Marsh's  apparatus,  yielded  very  large  arsenic  mirrors. 
20  cc.  were  precipitated  with  chloride  of  ammonium,  ammonia,  and 
chloride  of  magnesium.  The  voluminous  precipitate  was  filtered  off, 
etc.,  dried  at  21 2°,  on  a  tared  filter,  and  weighed,  as  NH4MgAs04+ 
H20,  ammoniated  arseniate  of  magnesium. 
The  remaining  40  cc.  were  used  for  different  qualitative  tests. 
The  total  amount  of  pigment  was  determined  by  extracting  one 
paper  with  ammonia,1  and  evaporating  the  blue  filtrate  on  a  watch- 
glass. 
From  five  papers,  of  before-named  size,  I  was  able  to  extract  a 
globule  of  metallic  copper  with  the  blow-pipe,  weighing  0*076  grm., 
=  \\  grain.  I  also  have  several  arsenic  mirrors,  arsenious  acid  (in 
beautiful  octahedrons  and  tetrahedrons,  visible  with  the  microscope), 
sulphide  of  arsenic,  etc.,  as  corpora  delicti,  on  hand,  each  sample  being 
extracted  from  one  piece  of  this  candy-paper. 
Owing  to  the  fact  that  "  Paris  green,"  if  perfectly  soluble  in  ammo- 
nia, is  considered  "  pure,"  manufacturers  often  adulterate  it  with  arse- 
nic, which  does  not  interfere  with  the  solubility.  This  seems  to  have 
been  also  the  case  with  the  pigment  analyzed,  the  amount  of  arsenic 
found  being  rather  large. 
The  analysis  was  executed  with  care,  and  the  correctness  of  the 
results  confirmed  by  duplicate  assays. 
Navarre,  O.,  Dec.  4,  1876. 
GLEANINGS  FROM  THE  FOREIGN  JOURNALS. 
By  the  Editor. 
Comparative  Assay  of  Male  Fern  The  rhizomes  collected  in 
the  spring  and  fall  are,  according  to  Kruse,  of  a  deeper  green  color 
and  a  stronger  odor  than  those  collected  in  summer.  To  ascertain 
the  variations  in  the  composition  of  the  rhizome  collected  at  different 
seasons  in  1874,  comparative  assays  were  made,  with  the  following 
results  : 
1  Practical  test  for  purity  of  Paris  green,  which  is  entirely  soluble  in  ammonia. 
