318  Intelligence  and  Miscellaneous  Articles. 
has  repeated  the  experiment  in  such  a  manner  that  this  surface  was 
concave  and  remained  so  in  spite  of  the  fact  that  the  volume  of 
water  increased  owing  to  expansion  by  heat  and  the  condensation 
of  vapour ;  but  now  in  this  case  a  large  number  of  vesicles  should 
have  rolled  towards  the  apex  of  the  concavity,  have  accumulated 
there,  and  therefore  must  soon  have  placed  themselves  in  contact 
with  the  fluid  surface :  but  nothing  in  the  result  was  different;  no 
cloud  disturbed  the  transparency  of  the  water. 
I  consider  the  above  experiment,  though  not  decisive,  yet  a 
very  powerful  argument  against  the  hypothesis  of  the  vesicular  con- 
dition. 
May  I  here  be  permitted  to  recall  another  experiment,  which  I  nave 
described  in  the  eighth  series  of  my  investigation  Sur  les  figures 
d'equilibre  d'une  masse  liquide  sans  pesanteur.  One  of  the  chief  ob- 
jections which  have  been  raised  against  the  vesicular  condition  is,  that 
the  air  contained  in  a  vesicle  would  be  exposed  on  the  part  of  the 
fluid  envelope  to  a  considerable  pressure,  the  effect  of  which  would 
be  that  this  air  would  gradually  dissolve  in  the  envelope,  and  would 
traverse  it,  by  which  the  vesicle  would  soon  change  into  a  complete 
globule.  But  when  a  laminar  calotte,  about  a  centimetre  in  diame- 
ter, is  formed  by  means  of  a  solution  of  1  part  of  Marseilles  soap  in 
40  of  water,  and  this  is  allowed  to  stand  in  an  atmosphere  laden 
with  aqueous  vapour,  it  sometimes  lasts  for  more  than  twenty-four 
hours  and  becomes  quite  black.  At  the  same  time  a  remarkable 
phenomenon  is  witnessed  ;  the  calotte  gradually  decreases  and  ulti- 
mately disappears, — from  which  it  follows  that  the  enclosed  air  has 
gradually  traversed  the  lamina.  This  lamina  is  indeed  far  thinner 
than  a  vesicle  would  be  ;  but,  on  the  other  hand,  theory  shows,  from 
the  difference  of  the  liquids  and  the  diameter,  that  in  the  interior  of 
a  vesicle  the  pressure  would  be  more  than  a  thousand  times  as  great 
as  in  the  interior  of  a  calotte  of  soap-solution  at  its  original  dimen- 
sions.— Bull,  de  VAcad.  Roy.  de  Belgique,  vol.  xxxii. 
ON  THE  ABSORPTION-SPECTRA  OP  CHLORINE  AND  CHLORIDE  OP 
IODINE.       BY  D.  GERNEZ. 
The  researches  of  Brewster,  of  W.  H.  Miller,  and  of  W.  A.  Miller 
have  made  known  the  absorption-spectra  of  the  coloured  vapours 
of  hyponitric  acid,  bromine,  iodine,  hypochloric  and  chlorous  acids, 
and  perchloride  of  manganese.  These  vapours  act  very  energetically 
on  light ;  and  in  a  thickness  of  only  a  few  centimetres  they  pro- 
duce characteristic  systems  of  lines  in  the  continuous  spectra  of  in- 
candescent solids. 
"When,  with  the  aid  of  a  spectroscope  with  only  one  prism,  we 
examine  the  effect  produced  by  an  increasing  thickness  of  these  sub- 
stances, we  first  observe  some  bands,  the  number  of  which  increases 
while  finer  lines  appear  and  the  primitive  bands  are  resolved  into 
groups  of  very  close  lines.  It  is  these  bands,  or  rather  the  most 
conspicuous  of  the  lines,  that  we  again  meet  with,  as  I  have  recently 
shown,  in  the  spectra  of  solutions  of  these  substances.     If  we  aug- 
