294  American  Philosophical  Society.  {AnVui^899arm* 
CONVERSAZIONE  of  the  AMERICAN  PHILO- 
SOPHICAL SOCIETY. 
The  annual  Conversazione  of  the  American  Philosophical  Society  at  Phila- 
delphia, was  held  at  the  hall  of  the  Society  on  Independence  Square,  Friday 
afternoon  and  evening,  May  12th. 
This  Society  is  the  oldest  of  its  kind  in  America,  having  been  founded 
by  Franklin  in  1743,  "  for  the  promotion  of  useful  knowledge."  The  custom 
of  holding  an  annual  conversazione  was  inaugurated  some  two  or  three  years 
ago  and  has  proved  a  very  attractive,  as  well  as  instructive,  feature  of  the  work 
of  the  Society. 
On  the  present  occasion,  which  was  marked  by  charming  social  simplicity, 
and  which  one  might  be  inclined  to  attribute  to  the  far-reaching  influence  of 
the  great  Franklin  himself,  addresses  were  made  at,  intervals  on  subjects  per- 
taining to  recent  advances  in  various  departments  of  science.  In  addition, 
exhibits  of  scientific  interest  were  arranged  around  the  rooms  for  the  inspection 
of  the  members  and  their  guests. 
Prof.  Arthur  W.  Goodspeed  described  "Roentgen  Ray  Work,"  using  for 
illustration  an  improved  Rumhkorff  coil  and  a  self-regulating  X-ray  tube,  both 
of  which  were  exhibited  by  Messrs.  Queen  &  Co. 
Dr.  Coleman  Sellers  described  the  manufacture  of  "Artificial  Graphite"  in 
the  electric  furnace,  in  connection  with  the  manufacture  of  carborundum. 
Carborundum,  which  is  silicon  carbide  and  next  to  the  diamond  in  hardness,  is 
manufactured  commercially  from  a  mixture  consisting  of  sand  527  per  cent., 
coke  34-8  per  cent.,  sawdust  107  per  cent,  and  salt  i*8  per  cent.,  the  following 
representing  the  reaction  involved  :  Si02  +  3C  =  SiC  2CO. 
Recently  it  has  been  found  that  when  a  carbide  is  heated  to  the  point  of 
decomposition  graphite  is  formed,  and  thus  but  one  step  is  involved  in  convert- 
ing carborundum  into  absolutely  pure  graphite.  Dr.  Sellers,  commenting  on 
the  discovery,  in  view  of  the  cheapness  with  which  electricity  is  furnished  by 
the  Niagara  Falls  Electric  Power  Company,  regarded  it  as  one  of  the  most  bril- 
liant of  modern  times.  A  number  of  specimens  furnished  by  Mr.  A.  G.  Ache- 
son,  of  Pittsburg,  was  shown  in  connection  with  this  subject. 
An  account  of  the  "New  Gases  of  the  Atmosphere  "  was  given  by  Dr.  G.  F. 
Barker,  those  present  being  invited  to  examine  the  spectra  of  argon  and  helium. 
This  was  a  concise  resume  of  the  history  of  the  five  gases  :  helium,  argon, 
metargon,  crypton  and  neon,  all  of  which  have  been  discovered  within  the  last 
five  years,  and  were  described  in  the  November,  1898,  number  of  this  Journal. 
Dr.  Barker  stated  that,  like  mercury,  zinc,  cadmium,  etc.,  these  new  elements 
are  all  monatomic,  and  the  most  interesting  problem  which  is  presented  in 
the  study  of  their  properties  is  the  question  as  to  whether  they  are  capable  of 
ionization. 
Prof.  C.  L.  Doolittle,  of  the  Flower  Astronomical  Observatory,  gave  a  brief 
talk  upon  the  "  Results  of  Recent  Astronomical  Work,"  diagrams  showing  the 
variation  of  the  latitude  of  the  earth  being  exhibited  in  connection  therewith. 
Dr.  S.  P.  Sadtler  gave  a  brief  account  of  "  Artificial  Indigo,"  in  which  he  re- 
ferred to  the  decline  in  the  commerce  of  madder  roots  after  the  introduction  of 
artificial  alizarin,  and  predicted  a  similar  fate  for  natural  indigo.  Continuing, 
he  said  that,  in  1881  a  patent  had  been  taken  out  for  artificial  indigo  and  that  in 
