256  Tobacco  Culture  in  Pennsylvania.  \Am)]^;^T.m' 
suppose  that  the  large  amount  of  ashes  which  some  have  obtained 
may  have  been  due,  in  part,  at  least,  to'the  bottom  leaves  having  been 
used  in  their  experiments. 
TOBACCO  CULTURE  IN  PENNSYLVANIA. 
BY  JOHN  ALFRED  WITMER,  PH.G. 
[Abstract  from  an  Inaugural  Essay.) 
The  cultivation  of  tobacco  was  not  carried  on  to  any  great  extent  in 
Pennsylvania  previous  to  the  late  civil  war ;  since  that  time  it  has 
increased  very  considerably.  The  author's  personal  acquaintance  with 
the  culture  of  this  commodity  is  limited  to  Lancaster  county,  Pa. 
The  seeds  which  have  been  collected  the  previous  autumn  are  sown 
(in  early  spring)  in  cold  frames.  These  frames  consist  of  large  oblong 
boxes,  without  bottoms,  two  or  two  and  a  half  feet  deep  by  three  feet 
wide,  and  covered  with  glass.  They  are  prepared  in  autumn  by  being 
filled  with  rich  earth  and  fertilizers.  In  selecting  a  site  for  these 
frames,  a  sheltered  spot  having  a  southern  exposure  is  preferred.  They 
are  additionally  protected  from  the  weather  by  being  covered  with 
straw,  &c.  Persons  making  "  plant-raising  "  a  specialty,  sow  as  early 
as  the  15th  of  February.  After  sowing,  the  frames  are  covered  with 
glass  alone  during  the  day,  and  sheltered  at  night.  The  earth  being 
kept  moist,  the  seeds  soon  sprout,  and  the  little  plants  appear.  Addi- 
tional care  must  now  be  taken  to  admit  the  sun  during  the  day  and  to 
protect  from  the  frosts  at  night.  Persons  not  desirous  of  having  plants 
early  or  for  sale  do  not  take  the  precautions  above  enumerated,  nor  do 
they  sow  as  early.  A  warm,  sunny  spot,  having  a  rich  soil,  or  one 
enriched  by  fertilizers,  is  sufficient  for  their  purposes.  When  quite 
young,  the  plants  are  frequently  infested  by  the  "  plant-louse,"  an 
insect  belonging  to  the  genus  "Aphis."  When  the  plants  have  attained 
the  height  of  several  inches,  they  are  transplanted  to  the  fields.  This 
is  rarely  done  before  the  15th  of  May  to  the  1st  of  June.  The  fields 
are  plowed  the  previous  autumn,  as  by  so  doing  it  is  thought  that  some 
of  the  insect  enemies  are  destroyed.  In  the  spring  the  soil  is  loosened, 
and  then  plowed  in  such  a  manner  as  to  form  ridges  one-half  to  one 
foot  high,  at  a  distance  of  four  to  five  feet  apart.  The  plants  are 
planted  on  the  tops  of  these  ridges,  at  a  distance  of  two  to  three  feet. 
A  wet  day  is  chosen,  as  the  plants  require  much  moisture  to  continue 
