Am.  Jour.  Pharrr. 
May,  1899. 
Editorial. 
235 
Schmidt  has  found  that  compounds  of  thorium  are  the  only  ones  endowed  with 
similar  properties.  Uranic  rays  have  been  frequently  called  Becquerel  rays  ; 
this  name  may  be  generalized  by  applying  it  also  to  Thoric  rays  and  all 
rays  of  that  character. 
While  making  certain  experiments  with  a  number  of  minerals  which  con- 
tained either  uranium  or  thorium,  for  the  purpose  of  measuring  the  conduc- 
tivity of  the  air  when  under  the  influence  of  hypophosphorescent  or  radio-active 
substances  it  was  noticed  by  S.  Curie,  that  in  some  cases  the  intensity  of  the 
action  was  quite  unexpected,  and  the  presence  of  another  element  was  imme- 
diately suggested.  After  considerable  experimenting  upon  one  of  these  min- 
erals, viz. :  pitch  blende,  a  body  was  obtained  by  chemical  means  which  was 
about  400  times  more  active  than  uranium.  This  body  is  supposed  to  be  a  new 
element  added  to  bismuth  and  it  is  proposed  to  call  it  Polonium.  Since  this 
research  M.  and  Mme.  Curie  with  G.  Bemont  have  "  discovered  in  pitch  blende 
indications  of  an  element  (radium)  allied  to  barium  in  its  chemical  properties, 
but  differing  in  its  radio-activity." 
The  action  of  uranic,  thoric  and,  polonic  rays  on  sensitive  plates  is  various. 
Those  of  thorium  are  the  least  active.  Uranium  compounds  give  an  impres- 
sion in  an  hour,  and  sulphide  of  polonium  produces  a  decided  action  in  from 
one-half  to  three  minutes. 
The  fluorescent  action  produced  by  the  compounds  of  uranium,  thorium  and 
polonium  on  platinocyanide  of  barium  are  equally  remarkable.  The  two  for- 
mer compounds  have  apparently  no  action,  whereas  the  sulphide  of  polonium 
has  a  very  distinct  action.  From  experiments  made  with  the  latter  compound, 
it  would  appear  "that  we  can  obtain  an  indefinite  amount  of  light  without  the 
expenditure  of  any  energy." 
In  a  paper  in  the  Chemical  News,  February  17,  1899,  from  which  we  have 
freely  quoted,  is  found  also  an  interesting  discussion  on  the  analogies  and  dif- 
ferences between  Becquerel  and  other  rays.  Becquerel  rays,  or  those  produced 
by  compounds  of  Uranium,  Thorium  and  Polonium,  are  characterized  by  the 
following  properties:  "They  render  gases  which  they  traverse  conductors  of 
electricity  ;  they  produce  photographic  impressions..  These  properties  do  not 
in  any  way  depend  on  the  past  or  present  action  of  light  on  bodies  emitting 
these  rays.  They  traverse  all  substances,  glass,  paper,  metals  and  liquids,  but 
are,  as  a  rule,  absorbed  to  a  great  extent.  Their  emission  appears  to  be  spon- 
taneous ;  it  is  constant,  and  indicates  the  presence  of  certain  elements  in  the 
active  substance.  The  spontaneous  emission  of  these  rays  appears  to  give  rise 
to  a  continuous  disengagement  of  energy  of  which  we  cannot  find  the  source. 
This  is  in  direct  contradiction  to  Carnot's  principle.  It  is  possible,  how- 
ever, to  conceive  of  the  production  of  the  phenomenon  in  different  ways. 
It  may  be  a  phosphorescence  of  considerable  duration  caused  by  the  action  of 
light.  It  may  be  an  emission  of  matter  accompanied  by  a  loss  of  weight  of  the 
radioactive  bodies  or  the  utilizable  energy  may  be  constantly  diminishing. 
Again,  it  may  be  a  secondary  emission  produced  by  rays  analogous  to  X-rays. 
But  it  may  well  be  asked  whether  Becquerel  rays  may  not  be  produced 
at  the  expense  of  the  heat  in  the  surrounding  medium,  contrary  to  Carnot's 
principle." 
In  view  of  the  knowledge  that  the  investigator  in  this  latter  part  of  the  nine- 
teenth century  is  bringing  to  light  and  establishing  thereby  an  apparently  new 
