366 
Liquefaction  of  Fluorine. 
Am.  Jour.  Pbarm. 
July,  1897. 
varies  between  8d.,  and  2s.  2d.  per  lb.,  the  highest  price  represent- 
ing the  value  of  English-ground  powder  from  closed  flowers  and  the 
lowest  powder  "  foreign-ground "  from  the  whole  plant.  This 
ground  whole  plant  appears  to  be  the  principal  sophistication, 
apart  from  the  coloring  matter,  found  in  commerce  at  the  present 
time. 
I  desire  to  acknowledge  my  indebtedness  to  Mr.  Charles  Umney 
for  very  fine  specimens  of  the  dry  flowers  of  C.  cinerarisefolium. 
THE  LIQUEFACTION  OF  FLUORINE.1 
By  H.  Moissan  and  J.  Dewar. 
The  physical  properties  of  a  large  number  of  mineral  and  organic 
compounds  of  fluorine  indicated,  theoretically,  that  the  liquefaction 
of  fluorine  could  only  be  accomplished  at  a  very  low  temperature. 
Whilst  the  chlorides  of  boron  and  silicon  are  liquid  at  ordinary 
temperatures,  the  fluorides  are  gaseous,  and  very  far  from  their 
points  of  liquefaction.  This  is  also  true  with  the  organic  com- 
pounds; chloride  of  eth}  1  boils  at  -J-  12°  C,  and  the  fluoride  of 
ethyl  at  320.2  Chloride  of  propyl  boils  at  -f-  450,  and  the  fluoride 
of  propyl  at  —  20.3 
Similar  observations  have  been  made  by  Paterno  and  Oliveri,4 
and  by  Vallach  and  Heusler.5 
phuric  acid  and  volumetrically  determining  the  converted  chlorophyll  as  glu- 
cose with  a  suitable  copper  solution.  For  my  own  purposes  I  should  unhesi- 
tatingly reject  the  sample  rather  than  take  this  unnecessary  trouble,  unless  a 
fee  were  attached  to  the  operation. 
1  M.  Moissan  brought  all  his  apparatus  for  the  production  of  fluorine  to  the 
Royal  Institution  on  the  occasion  of  his  lecture  there  on  Friday,  the  28th  of 
May.  The  next  day  the  writer  had  the  good  fortune  to  witness  in  the  labora- 
tories of  the  Institution,  by  M.  Moissan  aud  Professor  Dewar,  some  of  the 
experiments  which  resulted  in  the  liquefaction  of  fluorine.  These  experiments 
mainly  owed  their  success  to  the  unrivalled  appliances  for  the  production  of 
intense  cold  possessed  by  the  Institution,  and  the  skill  and  experience  of  Pro- 
fessor Dewar  and  his  assistants  in  preparing  a  special  apparatus  suitable  for  the 
examination  of,  and  experimenting  with,  fluid  fluorine,  and  in  the  manipula- 
tion of  large  quantities  of  liquid  air. — W.  C. 
2H.  Maissan,  "  Proprietes  et  Preparation  du  Fluorure  d'ethyle,"  Ann.  de 
Chim.  et  de  Phys.,  Series  6,  Vol.  XIX,  p.  266. 
3  Meslans,  Comptes  Rendus,  Vol.  CVIII,  p.  352. 
4  Paterno  and  Oliveri,  "Sur  les  trois  Acides  Fluobenzoiques  Isomeres,  et  sur 
les  Acides  Fluotoluidique  et  Fluoanisque,"  Gazetta  Chimica  Italiana,  Vol.  XII, 
p.  85,  and  Vol.  XIII,  p.  583. 
5  Vallach  and  Heusler,  Annates  de  Liebig,  Vol.  CCXLIII,  p.  219. 
