Our  Canaries 
59 
AVOID  TOO  MUCH  GLASS. 
At  the  same  time,  it  must  be  borne  in  mind  that  a  great  area  of  glass  is 
to  be  avoided,  if  possible,  on  account  of  its  rendering  the  whole  interior  of  the 
building  subject  to  extreme  fluctuations  of  temperature,  and  the  objectionable 
"  sweating,"  which  it  is  extremely  difficult  to  avoid  in  any  ordinary  building 
where  much  glass  is  a  feature.  Lighting  by  "skylights"  is  also  an  objectionable 
feature  in  many  ways,  and  should  be  avoided  in  all  cases  where  sufficient  light 
can  be  obtained  by  ordinary  windows.  These  should  be  of  a  fairly  good  type, 
close-fitting  to  exclude  the  fatal  cutting  draughts,  but  made  to  open  with  ease 
and  freedom,  so  that  they  may  be  utilised  at  any  time  in  fair  weather  to  give 
the  place  a  good  airing. 
WISED   SASH   FOB  WINDOW  FRAME. 
Useful  to  prevent  birds  escaping  from  the  aviary. 
Wire-covered  frames  must  be  made  to  fit  over  the  window  spaces,  which 
should  hang  on  hinges,  in  order  to  be  easily  movable  to  allow  free  and  easy 
access  to  the  windows.  (Never,  by  the  way,  place  any  serious  obstacle  in  the 
way  of  getting  the  windows  open,  as  this  is  apt  to  cause  needed  airings  to  be 
deferred  to  a  more  convenient  season  when  one  is  busy,  and  perhaps  omitted 
altogether.)  These  wire  frames  are  necessary  to  prevent  the  escape  of  birds, 
or  ingress  of  feline  marauders,  when  the  windows  are  open,  and  are  most  advisable 
for  the  latter  purpose,  even  when  the  birds  are  being  kept  in  cages. 
THOUGHTS  ON  VENTILATION. 
The  chief  difficulty  relating  to  this  feature  is  to  provide  for  a  thorough  and 
efficient  change  of  air  in  the  building  constantly  and  in  all  conditions  of  weather 
which  may  be  ruling  outside,  and  yet  to  avoid  all  draughts,  and  also  as  far  as 
possible  too  striking  contrasts  in  the  temperature  inside  the  house.  Any  system 
that  provides  for  a  progressive  and  gradual  change  to  be  going  on  automatically 
must  naturally  be  the  best  suited  for  the  purpose  in  view,  but,  unfortunately,  such 
