^"•/an^r.f's'""' }  Gleanings.  1 5 
temperature  not  exceeding  130°  C.  and  dry  sulphuretted  hydrogen 
passed  through  it.  The  product  is  subjected  to  fractional  distillation^ 
when  a  pure  acid  may  be  obtained,  which  crystallizes  in  a  refrigerating 
mixture,  and  fuses  at  8°,  6  C,  which  temperature  is  considerably  higher 
than  has  been  observed  heretofore. — Bull.  Soc.  Chim.  de  Paris^  i^74> 
p.  440. 
Dry  Acetate  of  Ammonium  is  obtained  by  Berthelot,  by  dissolving 
glacial  acetic  acid  in  ammonia,  keeping  the  retort  cool,  and  adding 
enough  water  to  prevent  the  crystallization  of  the  salt  during  the  neu- 
tralization ;  the  solution  is  evaporated  in  a  current  of  dry,  gaseous 
ammonia  until  the  liquid  solidifies  on  cooling.  It  is  then  introduced 
into  a  large  capsule,  and  this  placed  upon  caustic  lime,  under  a  large 
bell  glass,  in  which  a  considerable  quantity  of  ammonia  gas  is  injected. 
After  a  few  days  the  crystalline  mass  is  broken,  and  the  capsule 
replaced  as  before  upon  lime  in  an  ammoniacal  atmosphere,  under  the 
bell  glass.  When  this  operation  has  been  repeated  several  times,  a 
perfectly  pure  acetate  of  ammonium  is  obtained,  which  crystallizes  in 
large  needles,  like  nitrate  of  potassium,  and  resembling  formiate  of  am- 
monium ;  it  is  extremely  soluble  in  water,  and  does  not  possess  an  acid 
reaction. — Ibid. 
The  Composition  of  Pirsch-Baudoin^ s  Imitation  of  Silver  is  given  as 
follows:  Copper  71,  nickel  16-50,  cobalt  175,  tin  2*50,  iron  1*25^ 
zinc  7  (aluminium  1*5). — Pharm.  Cent.  Halle^  1874,  No.  42. 
Destruction  of  Insects  by  Composite. — Four  grains  of  a  good  insect- 
powder  sprinkled  upon  a  fly  contained  in  a  vial,  must,  according  to  H. 
Kalbruner,  produce  stupefaction  in  one  minute,  and  death  in  two  or 
three  minutes.  Tested  in  this  way,  he  found  the  flowers  of  the  fol- 
lowing plants  entirely  worthless :  Chrysanthemum  leucanthemuin^  L.^ 
Chrys.  coronarium.^  L.,  Anthemis  arvensis^  h.^  A.  cotula^  h.^  A.  tinctoria^  L.,. 
A.  nobilis.,  L.,  and  Inula  pulicaria.^  L.  ;  likewise  the  herb  of  Pyrethrum 
roseum.^  M.  B.,  and  P.  cinerar  ice  folium^  Trev.  A  slight  stupefying  effect 
was  produced  by  the  flowers  of  Tanacetum  vulgar e.^  Lin.,  and  Pyrethrum 
corymb osum^  Sm.  The  flowers  of  Pyr.  parthenium.^  Lin.,  and  Pyr.  in- 
odorum^  Lin.,  stupefy  flies  and  kill  them  in  from  one  to  two  hours;  their 
value  as  insecticides  is  therefore  very  slight.  A  few  commercial  insect- 
powders  come  up  to  the  requirements  mentioned  before,  while  others 
require  fifteen  to  thirty  minutes  to  kill  a  fly.  The  flowers  of  Pyr.  cine- 
rar  ice  folium.^  which  is  indigenous  to  Dalmatia,  were  observed  to  be 
rather  more  active  than  those  of  P.  roseum.^  perhaps  because  the  latter 
