408  Ozone  in  a  Concentrated  State.  {^d^illn"' 
applied  to  any  apparatus  for  making  oxygen.  When  the  inductorium 
is  in  action,  the  operator  has  only  to  disengage  oxygen,  and  to  collect 
the  concentrated  ozone. 
It  furnishes  readily  odorous  oxygen  charged  with  60  to  120  milli- 
grammes per  litre  of  absolute  ozone,  accordingly  as  one  operates  at 
+  15°  or  —  30°  Cent.  This  proportion  may,  perhaps,  be  still  more 
augmented.* 
Previous  to  1854,  the  electrolysis  of  water  gave  three  to  five  milli- 
grammes of  ozone  per  litre  of  odorous  gas.  (In  1856,  Prof.  Andrews 
could  only  obtain  4*1  milligrammes  per  litre.)  In  1855,  my  chemi- 
cal process  (Ba  02  -f  S03)  nearly  doubled  this  quantity.  It  is  there- 
fore now  possible  to  look  forward  to  the  complete  conversion  of  oxy- 
gen into  ozone.  If,  however,  the  transformation  of  oxygen  into  ozone 
has  a  limit,  I  imagine  that  by  the  aid  of  powerful  refrigerating  appli- 
ances, we  may  yet  be  able  to  separate  the  two  gases.  In  this  case, 
the  similarity  of  chemical  characteristics  between  ozone  and  chlorine 
renders  the  liquefaction  of  the  former  by  pressure,  and  reduction  of 
temperature,  extremely  probable. 
Having  ozone  at  my  disposal  fifteen  to  twenty  times  stronger  than 
has  hitherto  been  obtained,  I  have  been  enabled  to  review  many  of  the 
most  important  properties  of  this  substance,  and  besides  to  determine 
the  part  it  plays  in  nature. 
With  the  ozonizing  tube  the  following  lecture  experiments  may  be 
performed.  The  gas  can  be  collected  over  water,  in  flasks  of  the 
capacity  of  half  a  litre  (water  dissolves  about  the  100,000th  part  of 
its  weight  of  ozone) : 
Silver. — A  bright  leaf  of  silver  is  immediately  blackened  in  most 
ozone  (Schonbein).  The  oxide  of  silver  formed  is  alkaline,  and  pro- 
duces a  strong  blue  with  reddened  litmus  paper  (A.  H.)  In  spite  of 
this  absorption  of  ozone  by  the  silver,  the  volume  of  the  gas  under- 
goes no  visible  diminution  (A.  H.) 
Iodide  of  Potassium. — A  solution  of  iodide  of  potassium  poured 
*I  have  arranged  an  apparatus  by  which  I  have  produced  as  much  as  188 
milligrammes  of  ozone  per  litre  of  oxygen.  The  research  is  still  going  on.  A 
special  disposition  has  also  enabled  me  to  collect  at  the  same  time,  but  sepa- 
rately, the  ozone  produced  by  the  exterior  electrode  ;  but,  if  the  ozone  gene- 
rated by  the  negative  electrode  is  afterwards  made  to  pass  over  the  positive 
electrode,  there  is  a  partial  destruction  of  ozone,  and  the  total  quantity  col- 
lected is  less  than  that  which  a  single  pole  affords. 
