74  ON  THE  DESTRUCTION  OF  NOXIOUS  INSECTS. 
volatile  essential  oil,  renders  the  conservation  of  this  principle 
extremely  difficult. 
Of  all  the  methods  for  applying  the  powder  to  plants  attacked 
by  insects,  including  the  vine,  the  bellows  will  best  accomplish 
the  object.  As  there  is  only  a  small  quantity  of  powder  thrown 
at  once,  the  loss  will  be  very  small,  whilst  in  any  other  way  a 
good  deal  of  it  will  fall  upon  the  ground.  The  powder  should 
be  directly  applied  to  the  parts  operated  on,  and  with  care  and 
precaution  it  may  be  made  to  penetrate  into  the  most  accessi- 
ble part  of  a  plant.  If,  for  instance,  a  plant  has  been  attacked 
by  plant  lice,  which  are  often  hidden  or  masked  by  thick  foli- 
age, it  will  become  necessary  to  turn  aside  this  foliage,  so  as  to 
have  the  insects  exposed,  and  the  powder  directly  brought  into 
contact  with  them. 
In  all  cases  these  operations  should  take  place  on  a  warm  day, 
the  morning  being  always  preferable.  A  slight  moisture  arising 
from  the  morning  dew  will  make  the  powder  more  easily  adhere 
to  the  spots  where  it  is  applied,  and  maintain  its  properties  long 
enough  to  cause  the  death  of  the  insects.  The  insufflation  should 
be  renewed  several  times,  according  to  the  nature  and  number 
of  insects  to  be  destroyed.  The  first  operation  generally  stupi- 
fies  them,  while  at  the  second  or  third  application  they  lose 
their  strength,  fail  to  the  ground,  and  die  sooner  or  later. 
In  order  to  prevent  the  ravages  of  the  wheat-midge,  the  pow- 
der is  mixed  with  the  grain  to  be  sown,  in  the  proportion  of 
about  two  ounces  to  two  or  three  bushels,  which  will  save  a 
year's  crop. 
For  insects  in  dwellings  the  insufflation  may  be  performed  by 
bellows  of  a  smaller  size  than  those  used  in  agriculture  and  hor- 
ticulture. Proper  care  should  be  taken  to  make  the  powder 
penetrate  to  the  recesses  where  the  insects  lodge.  Household 
furniture  ought  to  be  scrupulously  searched,  and  bedsteads  and 
sofas  sprinkled  in  the  evening.  By  continuing  this  for  several 
days,  the  premises  will  be  thoroughly  rid  of  insects. 
For  the  preservation  of  furs,  woollen  garments,  or  patterns, 
it  is  necessary,  at  the  approach  of  spring,  to  sprinkle  the  arti- 
cles abundantly  'with  the  powder,  the  object  in  contemplation 
being,  not  the  destruction  of  the  insects,  but  the  preventing  their 
reappearance. — Pharm.  Jour,  and  Trans.,  Loud.,  Oct.,  1863, 
from  the  Technologist. 
