G29 
in  its  Effect  on  Cultivation. 
in  the  north  of  Scotland.  The  temperature  of  the  soil  at 
12  inches  below  the  surface  generally  attains  its  maximum  in 
September,  and  is  frequently  5°  higher  in  well-drained  land  than 
on  the  surface,  and  at  the  surface  2°  higher  than  it  is  in  the 
air.  The  temperature  of  the  air  frequently  suffers  a great  dimi- 
nution about  the  21st  of  this  month;  and  almost  every  year 
stormy  weather  is  experienced  between  the  21st  of  September 
and  the  3rd  of  October  ; and  I have  frequently  seen  corn  that 
was  not  carried  before  the  autumnal  equinox  still  in  the  field 
during  the  middle  of  October.  This  month  had  a temperature 
of  5°  above  the  mean  in  1846. 
October  in  its  general  mean  temperature  again  approaches  to 
the  mean  of  the  year,  being  somewhat  lower  than  the  mean  in 
the  south-eastern  and  midland  counties,  and  higher  in  the  west  and 
north.  After  the  first  week  of  this  month  the  weather  is  com- 
monly fine  ; and  during  the  whole  of  it  the  temperature  of  the 
soil  is  much  higher  than  that  of  the  air.  In  the  south-west  of 
Ireland  and  of  England  the  average  temperature  is  52°;  in 
the  eastern  and  midland  counties  48°  ; and  in  the  north  of  Scot- 
land 4/°. 
November  has  a mean  temperature,  varying  from  46°  in  the 
south-west  to  4L°  in  the  south-east,  and  42°  in  the  south-west  of 
Scotland  to  40°  in  the  eastern  parts.  There  is  less  variation  be- 
tween the  day  and  night  in  this  and  the  following  month  than  in 
any  other  during  the  season  : the  usual  range  of  the  thermometer 
is  from  54°  to  29°. 
The  mean  heat  of  December  is  46°  in  the  south-wrest,  and  38° 
in  the  south-east,  and  is  but  little  below  the  latter  temperature 
through  the  whole  of  Scotland.  In  the  south-western  parts  of  the 
British  Islands  vegetation  goes  on  during  the  whole  of  this  month  ; 
and  persons  visiting  Ireland  may  perceive  by  the  greenness  of  its 
pastures,  that  it  deserves  the  name  of  the  Green  or  Emerald  Isle. 
It  is  proverbial  in  the  north  of  England  that  cold  sets  in  at  Christ- 
mas ; and  very  generally  it  is  during  the  last  week  in  December 
that  real  cold  weather  begins.  The  lowest  temperature  on  record 
was  on  the  25th,  in  the  great  frost  of  1795-6,  when  it  sank  to 
zero.  The  usual  range  of  heat  during  this  month  is  from  50°  to 
20°  of  Fahrenheit. 
I now  come  to  the  third  subject,  viz.,  “ Different  amount  of 
Insensible  Vapour  in  the  Atmosphere  on  the  Western  and  Eastern 
Sides  of  England  and  Ireland.” 
This  part  of  the  subject  has  been  partially  anticipated : and 
that  the  following  remarks  may  be  fully  understood,  and  conse- 
quently really  useful,  I shall  in  the  first  place  explain,  as  briefly 
as  may  be,  the  laws  on  which  the  formation  of  vapour  and  its 
presence  in  the  atmosphere  depend. 
The  earth  is  surrounded  by  two  atmospheres — one  of  air,  and 
