Intelligence  and  Miscellaneous  Articles.  155 
tions  of  granitic  gneiss  and  mica-schist  into  granite  alone,  and  the 
marked  traces  of  bedding  and  other  signs  of  stratification  that  appear 
in  the  granite,  to  which  the  author  ascribed  a  metamorphic  origin. 
He  also  noticed  the  marks  of  ice- action  observed  by  him  in  this 
region,  and  referred  especially  to  some  remarkable  fluted  bosses  of 
qnartzite,  and  to  the  formation  of  some  small  lakes  by  the  scooping 
action  of  ice. 
3.  "  Memoranda  on  the  most  recent  Geological  Changes  of  the 
Rivers  and  Plains  of  Xorthern  India,  founded  on  accurate  surveys 
and  the  Artesian  well-boring  at  Umballa,  to  show  the  practical 
application  of  Mr.  Login's  theory  of  the  abrading  and  transporting 
power  of  water  to  effect  such  changes."     By  T.  Login,  Esq.,  P.R.S.E. 
The  author  commenced  by  referring  to  the  general  conditions  of 
the  surface  of  the  country  under  consideration,  and  to  the  evidence 
afforded  by  it  of  a  great  decrease  in  the  amount  of  rainfall,  and  a 
great  change  in  the  nature  of  the  rivers.  His  object  was  to  show 
that  the  superficial  deposits  of  the  plains  of  India  were  formed  by 
the  action  of  mountain-streams,  the  deposits  being  irregular  trans- 
versely, but  exhibiting  a  uniform  section  longitudinally,  in  a  curve 
which  the  author  believed  to  be  a  true  parabola,  as  indicated  by 
Mr.  Tylor.  The  connexion  of  this  with  the  author's  theory  as  to 
the  transporting  power  of  water  was  indicated.  The  author  also 
showed  that  the  beds  of  the  large  Indian  rivers  are  rising  rather 
than  being  lowered,  and  pointed  out  that  this  was  in  accordance 
with  his  theoiy. 
XVIII.  Intelligence  and  Miscellaneous  Articles. 
ON  THE  SPECTRUM  OF  HYDROGEN  AT  LOW  PRESSURE. 
BY  G.  M.  SEABROKE,  ESQ. 
DURING  the  late  summer  months  I  have  been  comparing  the  lines 
given  by  hydrogen  in  the  spectroscope  with  the  lines  of  the  solar 
spectrum,  for  the  purpose  of  ascertaining  whether  any  lines  in  the 
sun's  chromosphere  were  due  to  hydrogen,  besides  those  usually 
supposed  to  be  due  to  this  element.  The  observations  are  as  yet 
incomplete  ;  but  as  it  will  be  some  months  before  I  can  again  pro- 
ceed, I  therefore  produce  the  results  obtained  up  to  the  present 
time.  The  experiments  have  been  conducted  in  a  room  adjoining 
the  Temple  Observatory  lately  erected  at  Rugby.  My  mode  of 
proceeding  has  been  briefly  as  follows : — I  use  a  vacuum-tube  con- 
taining hydrogen,  and  connected  with  a  Sprengel's  air-pump.  The 
tube  is  of  the  ordinary  form,  having  the  part  between  the  bulbs, 
into  which  the  platinum  wires  pass,  about  ^  inch  internal  diameter. 
The  pressure  in  the  tube  varied  from  3  to  4  millims.  of  mercury. 
Preliminary  experiments  showed  that  at  this  pressure  the  lines  ap- 
peared most  distinct ;  but  a  slight  change  of  pressure  near  4  millims. 
made  little  alteration  in  the  lines.  There  is  a  battery  of  twelve 
Smee's  to  work  the  coil  for  passing  the  spark  in  the  vacuum-tube. 
