530 
THE  ADMIEALTT  ASTEOXOMICAL  EXPEEDIEXT 
August  21  . 
. . . 18-9 
August  22 
. . . 16-7 
August  23  . 
. . . 14-1 
August  24  . 
. . . 17-0 
September  1 . 
. . . 29-2 
September  2 . 
. . . 29-5 
September  3 . 
. . . 27-5 
September  4 . 
. . . 24-6 
September  5 . 
. . . 22-2 
September  6 . 
. . . 23-9 
September  8 . 
. . 24-5 
September  9 . 
. . 22-3 
September  11 
. . 25-3 
September  12  . 
. . 30-1 
September  13  . 
. . 29-2 
September  14  , 
. . 32-5 
September  15 
. . 39-6 
September  16  . 
. . 36-9 
September  17  . 
. . 34-1 
[Section  added  during  the  printing.] 
(10.)  Epoch  of  maximum  Summer  Heat. 
Most  intimately  connected  with  the  results  just  given,  must  be  the  epoch  of  maximum 
annual  heat  at  the  surface  of  the  ground  ; and  attention  was  called  in  1820  by  the  learned 
Leopold  von  Buch,  to  a very  remarkable  anomaly  in  the  annual  march  of  temperatm-e 
for  Las  Palmas,  the  capital  of  Grand  Canary ; in  accordance  with  which  the  gi-eatest 
heat  was  experienced  there  in  the  month  of  October;  and  this  resnlt  seemed  all  the 
more  noteworthy,  as  a series  of  observations  at  Santa  Cruz,  in  Teneriffe,  showed,  he 
thought,  no  deviation  of  a similar  kind. 
On  compariag,  however,  the  numbers  given  by  him  with  the  more  numerous  results 
since  ascertained  for  other  parts  of  the  world,  it  appeared  to  us  that  the  Santa  Cruz 
epoch  of  greatest  heat,  though  earlier  than  that  of  Las  Palmas,  is  yet  sensibly  behind 
the  normal  period.  The  question  therefore  was  then  raised, — Does  the  anomaly  stiQ  exist, 
and  to  what  amount  1 Our  own  observations  extend  over  too  short  an  interval  to  settle 
the  point ; but  some  of  the  instruments  which  we  left  behind  in  Orotava,  furnished  to  us 
in  the  first  instance  by  the  liberality  of  Admiral  Fitzroy,  have  since  been  used  with  so 
much  intelligence,  and  observed  with  daily  for  a period  of  thirteen  months,  by  Herr 
Kreitz,  watch-maker  of  that  city,  that  they  have  afibrded  valuable  data  for  the  pui-pose ; 
and  the  results  of  his  9 a.m.  observations  alone  are  exhibited  in  the  following  Table, 
together  with  those  on  which  Von  Buch  depends,  viz.  10  years’  observations  ending,  it  is 
believed,  in  1816,  in  Las  Palmas,  Grand  Canary,  by  Dr.  Bandini  de  Gatti,  and  2^  years 
of  observations  in  Santa  Cruz  de  Tenerifie,  by  Don  Francisco  Escolar  in  1808,  1809, 
and  1810.  These  are  reduced,  for  facility  of  comparison,  to  Fahrenheit’s  scale;  not 
so  much,  be  it  remembered,  for  contrasting  their  absolute  temperatiu'es,  which  would 
include  instrumental  corrections  that  are  unknoAvn,  ui  addition  to  secular  changes,  as  for 
the  sake  of  their  differences  from  month  to  month,  which  are  free  from  those  manifest 
sources  of  error. 
