484 
THE  ADMIEALTY  ASTEOXOMICAL  EXPEETAfEXT 
the  telescope.  Of  all  the  subjects  connected  with  the  lunar  surface,  to  which  attention 
may  be  directed,  none  perhaps  is  so  important  as  the  detection  of  what  may  be  called 
the  dynamic  wrinkles  of  lava  streams.  These  at  once  distinguish  the  lava  sti-eam  from 
the  avalanche  of  stones ; and,  as  would  appear  on  the  Peak,  lead  to  much  insight 
regarding  the  temperature,  fluidity,  and  order  of  the  emitted  streams.  From  the  small 
size,  however,  of  such  wrinkles  at  Teneriffe,  the  successful  observation  of  them  in  the 
moon  would  demand  the  best  of  existing  telescopes,  the  highest  magnifying  power,  and 
a rarefied  mountain  atmosphere. 
.Tupiter  near  the  zenith  was  a sight  very  different  from  anything  that  European  astro- 
nomers have  had  for  many  years  past ; I attacked  it  therefore  with  zeal  as  to  optical 
features.  At  Guajara,  with  the  Sheepshanks  telescope,  it  was  remarkably  well  defined, 
the  belts  clear,  and  the  shadow  of  a satellite  occasionlly  crossing  the  disk  was  strong ; but 
with  the  exception  of  a scolloped  or  festooned  appearance  in  one  of  the  belts,  nothing 
new  was  seen.  The  interpretation  of  this  peculiarity  was  left  for  the  Pattinson  equato- 
rial at  Alta  Vista.  There,  -svith  a power  of  360,  the  bright  spaces  between  the  belts 
resolved  themselves  into  masses  of  cumuli,  cumuloni,  and  cumulostrati, — the  drift  doubt- 
less of  the  Jovian  trade-wind, — in  their  forms  and  gatherings  so  precisely  like  those 
which  the  terrestrial  trade  was  accumulating  round  Teneriffe  below  our  feet,  that  I could 
not  avoid  applying  the  same  name  to  similar  forms. 
Three  drawings  of  these  appearances — they  might  almost  be  called  revelations — in 
Jupiter  are  inserted  in  Plates  XXXIII.  and  XiXXilV.  The  originals  Avere  begun  and 
finished  at  the  end  of  the  telescope,  and  each  was  made  on  a different  evening,  and  with- 
out any  reference  to  the  previous  Aiews ; so  that  the  one  may  be  used  against  the  other,  in 
determining  the  probable  error  in  the  representation  of  any  particular  feature  of  interest. 
Due  allowance  must  of  course  be  made  for  the  change  of  the  mean  meridian  each  night ; 
indeed  during  the  time  occupied  in  the  di’awing,  the  shifting  of  the  whole  of  the  forms, 
from  rotation  of  the  planet,  was  most  perceptible  AAothout  appljfing  measurement ; but 
over  and  above  this,  there  Avere  minute  yet  indubitable  changes  of  shape  in  the  cloudy 
appearances  during  two  hours. 
Of  Saturn  two  draAvings  Avere  made,  but  beyond  satisfactorily  shoAA'ing  the  fine  division 
of  the  outer  ring,  there  was  little  to  be  done  on  account  of  the  Ioav  position  of  the 
planet.  One  of  the  draAvings,  hoAvever,  may  be  referred  to  (a’oI.  6,  page  28)  for  tlie 
appearance  presented  in  the  telescope ; the  second  Avas  a mere  sketch  taken  the  folloA\  - 
ing  night  to  test  the  characteristics  of  the  first. 
A single  drawing  should  not  be  looked  on,  by  itself,  as  of  importance  in  the  present 
state  of  astronomy ; for  how  can  others  than  the  artist  prove  the  reality  in  natm-e  of 
anything  they  may  find  in  that  one  document,  when  this  alone  is  before  them  ? A bad 
designer  will  often  unconsciously  give  an  erroneous  figure ; and  though  intending  to 
show  perhaps  the  blurred  outline  he  actually  saAv,  may  yet,  by  using  a pen  in  place  of  a 
brush,  represent  the  erroneous  appearance  as  haAlng  all-perfect  definition,  and  cause  the 
juxtaposition  of  full  Avhite  with  deep  black : and  if  he  has  put  in  these  things  and  a 
