40  Mr.  hunter  on  the  Heat , 8cc. 
this  kind  happened  this  winter  in  his  Majefty’s  garden'  at 
Ketw.  The  Erica  arborea  or  Tree-heath,  a native  of 
Spain  and  Portugal,  which  had  kept  its  health  extremely 
well  againft  a garden-wall  for  four  or  five  years,  though 
covered  with  , a:  mat,  was  killed  by  the  cold,  and  then 
being  frozen  fplit  into  innumerable  pieces'^.  But  the 
queition  is,  is  every  tree  dead  that  is  frozen?  I can  only 
jay,  that  in  all  the  experiments  I ever  made  upon  trees 
and  fhrubs,  whether  in  the  growing  or  active  ftate,  or  in 
the  paffive,  that  whole  <jr  part  which  was  frozen,  was 
dead  when  thawed. 
The  winter  177 { afforded  a very  favourable  op- 
portunity for  making  experiments  relative  to  cold, 
which  I carefully  availed  myfelf  of.  However,  pre- 
vious to  that  winter,  I had  made  many  experiments 
upon  vegetables  refpecting  their  temperature  compa- 
ratively with  that  of  the  atmofphere,  and  when  they 
were  in  their  different  ftates  of  activity : I there- 
fore examined  them  in  different  feafons,  with  a 
(g)  This  muft  be  owing  to  the  fap  in  the  tree  freezing,  and  occupying  a 
larger  fpace  when  frozen  than  in  a fluid  ftate,  ftmilar  to  water;  and  that  there 
is  a fufftcient  quantity  of  fap  in  a tree  newly  killed. is  proved  by  the  vaft  quan- 
tity which  flows  out  upon  wounding  a tree.  But  what  appeared  moft  remarka- 
ble to  me  was,  that  in  a walnut-tree,  on  which  I made  many^of  my  experi- 
ments, I obferved  that  more  fap  iflued  out  in  the  winter  than  in  the  fummer.  In 
the  fummer,  a hole  being  bored,  fcarcely  any  came  out ; but  in  the  winter  it 
flowed  out  abundantly* 
view 
