and  Circulation  of  the  Blood.
133
Before  I  close  this  Chapter,  I  ſhall  briefly
communicate  some  Experiments,  I  had  the
Pleasure  of  making  last  Summer,  with  my
most  ingenious  and  valuable  Friend  Doctor
ALEXANDER  STUART,  Physician  to  her  late
Majesty,  in  order  to  view  the  Circulation  of  the
Blood  by  the  Solar  or  Camera  Obscura  Microscope, ¬
  which  has  the  Advantage  of  magnifying
Objects  beyond  any  other  sort  of  Microscope:
but  must  refer  the  Curious  to  a  more  full
Account  thereof  laid  by  this  Gentleman  before ¬
  the  Royal  Society,  and  which  will  be
published  in  the  Philosophical  Transactions.
I  must  first  describe  a  particular  Apparatus,
invented  by  the  Doctor,  for  examining  the
Circulation  of  the  Blood  in  Frogs,  Mice,
Bats,  or  any  Creatures  of  the  like  Size.  In
this  Contrivance,  the  Looking-glass,  Tube,
and  convex  Lens  are  just  the  same,  and
placed  in  the  Hole  of  a  Window-Shutter  in
the  same  manner  as  described  Pag.  22.  But
here,  instead  of  using  WILSON's  little  Pocket
Microscope,  he  has  got  the  Belly-Part  of  a
large  Reflecting  one  fixed  horizontally  on  a
Pedestal,  at  a  Height  exactly  equal  to  the
Tube.  This  stands  on  a  little  Shelf  made
to  support  it;  and  to  the  Snout  thereof,
which  lies  on  a  Level  with  the  Tube,  the
Magnifiers  are  screwed.  The  Object  being
extended  and  fastened  with  Strings  and  Pins
on  a  Frame  convenient  for  the  Purpose,  is
applied  between  the  Tube  and  the  Magnifier: -