108 
THE  PARIS  EXPOSITtON. 
cabinet  of  specimens  collected,  and  the  various  improvements  in 
chemistry  and  pharmacy  suggested  from  time  to  time  were  in- 
vestigated and  reported  upon  by  the  members. 
THE  PARIS  EXPOSITION  OF  1867. 
By  the  Editor. 
(Continued  from  page  13.) 
The  English  Section. — One  of  the  most  remarkable  groups  in  the 
whole  Exposition  (though  not  in  class  44)  was  that  of  Messrs.  Johnson 
Matthey  &  Co.,  of  Hatton  Garden,  London,  which,  from  its  connection 
in  many  ways  with  chemical  manufacturing,  we  will  notice  here.  The 
display  consisted  of  platinum  apparatus  of  various  kinds,  from  immense 
stills  capable  of  concentrating  eight  tons  of  oil  of  vitriol  per  diem,  to  the 
smallest  crucibles,  tubes,  foil  and  wire  ;  specimens  of  rare  metals,  metal- 
lic salts  and  a  few  minerals,  the  entire  collection  valued  at  $100,000. 
The  largest  still  was  valued  at  $12,500  in  gold,  the  smaller  $8,200.  Each 
still  was  furnished  with  a  decanting  and  cooling  syphon,  by  which  its  con- 
tents, when  properly  condensed,  could  be  at  once  drawn  off  into  carboys. 
The  metal  used  in  this  apparatus  is  of  great  purity,  being  melted  by  the 
process  of  Deville,  (really  that  of  Dr.  Hare,  by  the  oxhydrogen  blow-pipe). 
The  chief  merit  of  these  stills  consisted  in  the  avoidance  of  gold  solder 
joints,  which,  from  variation  in  expansibility  or  for  electrical  reasons,  are 
more  disposed  to  give  way  than  other  parts.  Each  boiler  is  a  single 
piece  of  metal,  made  by  hammering  and  fusing  the  joints  with  the  blow- 
pipe by  the  autogenic  method,  just  as  plumbers  join  leaden  apparatus  by 
fusing  the  edges  together,  so  as  to  have  a  continuous  platinum  surface 
throughout,  an  advantage  over  solder-joints,  easily  appreciated  by  man- 
ufacturing chemists.  A  single  ingot  of  fused  platinum  valued  at  $5500, 
used  in  making  the  smaller  still  boiler,  was  shown.  A  platinum  alembic, 
used  for  refining  gold  and  silver  salts,  suitable  for  mint  refineries  and  for 
chemists,  was  exhibited,  worth  $1500.  These  platinum  vessels,  though  ex- 
pensive at  first,  effect  a  great  economy  in  the  long  run,  by  avoiding  loss 
from  breakage  of  glass  and  porcelain.  Platinum  tubes  of  all  sizes,  with 
platinum  joints,  crucibles,  spatulas,  foil  and  wire  ;  but  the  most  attractive 
object  to  the  chemist  was  the  remarkable  display  of  the  rare  metals, 
among  which  were  rhodium,  iridium,  osmium,  ruthenium,  magnesium,  thal- 
lium, chromium,  titanium  and  manganum.  Supplementary  to  these  was 
a  collection  of  metals  in  cylinders  of  the  same  diameter  and  weight,  but 
the  length  of  each  varied  with  its  specific  gravity,  each  cyHnder  weighing 
a  kilogram,  (over  two  pounds  av.).  showing  on  what  a  magnificent  scale 
these  metallurgists  got  up  their,  display.  The  length  of  each  cylinder 
was  of  course  in  ratio  to  its  specific  gravity,  the  lighter  metals  being  long 
and  the  heavier  short.    They  were  contained  in  glass  tubular  vessels  and 
