in  its  Effect  on  Cultivation. 
645 
7th.  The  indications  of  the  barometer  are  much  more  correct 
in  summer  than  winter. 
8th.  If  the  barometer  continue  to  fall  in  wet  weather,  then  a 
continuance  of  rain  may  be  expected. 
9th.  Pay  little  attention  to  the  absolute  height  of  the  baro- 
meter, but  to  its  changes ; and  if  it  has  been  very  low  and  com- 
mences even  to  rise  rapidly , it  will  probably  rain  in  a few  hours  ; 
but  the  rain  will  not  generally  be  of  long  continuance.  This  is 
owing  to  cold  air  condensing  the  vapour,  and  at  the  same  time 
adding  to  the  weight  of  the  air. 
The  signs  of  rain  deduced  from  the  clouds,  are  with  respect  to 
their  changes  into  Nimbus,  &c.,  known  to  all  men  used  to  the 
open  air,  so  much  better  than  I could  express  their  changes  in 
writing,  that  I pass  them  over.  But  the  following  results  of  ex- 
perience I have  found  rarely  to  fail  : — 
1st.  If  the  clouds  move  in  the  higher  regions  of  the  air  in 
opposition  to  the  wind  at  the  surface  of  the  earth,  rain  generally 
soon  follows,  in  consequence  of  the  mutual  action  of  these  con- 
trary currents. 
2nd.  If  on  a foggy  morning  the  higher  regions  of  the  air  are 
also  cloudy  (which  may  be  known  by  the  particular  blackness  of 
the  fog),  rain  is  pretty  sure  in  the  course  of  the  day — the  air  being 
unable  to  absorb  the  fog  in  the  state  of  insensible  moisture,  in 
consequence  of  being  already  saturated  in  the  higher  regions. 
3rd.  A halo  around  the  sun  or  moon  (being  caused  by  fine 
rain  already  falling  in  the  upper  regions)  is  sure  to  be  followed 
by  rain. 
4th.  If  in  hilly  districts  the  fog,  instead  of  clearing  away,  ap- 
pears to  roll  along  the  sides  of  the  hill,  rain  generally  falls,  com- 
mencing about  an  hour  before  noon,  or  from  that  time  to  1 p.m. 
This  in  the  northern  parts  of  England  I have  observed  for  very 
many  years,  and  scarcely  ever  known  to  fail. 
5th.  If  the  sky  be  bright  and  clear  in  the  morning,  and  after- 
wards clouds  begin  to  form  near  the  horizon,  rain  is  almost  sure 
to  take  place  during  the  day. 
6th.  If  in  the  morning  the  clouds  have  a yellow  or  yellow  and 
red  tinge,  rain  is  almost  sure  to  take  place  during  the  day,  for  it 
shows  that  there  is  more  vapour  in  the  air  than  the  sun’s  rays 
can  easily  penetrate,  and  hence  any  disturbance  will  cause  it  to  be 
condensed. 
7th.  I may  add,  that  there  is  a feeling  about  the  air  when 
charged  with  moisture,  that  many  persons  can  easily  detect  even 
without  the  aid  of  an  hygrometer,  or  any  other  instrument,  and 
for  many  years  I have  been  able  to  tell  within  a degree  the  differ- 
ence between  the  dew  point  and  the  heat  of  the  air.  I have 
also  met  with  many  others  who  could  do  the  same,  and  these  per- 
