£78 
VARIETIES. 
popular.  Those  thai  are  given  are  noted  more  particularly  for  the  peculiar 
character  of  their  odor,  and  are  selected  from  more  than  a  thousand  recipes 
lhat  have  been  practically  tried. 
Those  readers  who  require  to  know  any  thing  about  the  simple  extracts 
df  flowers  are  referred  to  them  under  their  respective  alphabetical  titles. — 
Annals,  of  Pharmacy,, 
Electro- Magnetic  Engraving  Machine.— This  machine  is  somewhat  on  the 
principle  of  the  well  known  planing  machine.    The  drawing  to  be  copied 
and  the  plate  to  be  engraved  are  placed  side  by  side,  on  the  moyeable  table 
or  lid  of  the  machine  ;  a  pointer  or  feeler  is  so  connected,  by  means  of  a 
horizontal  bar,  with  a  graver,  that  when  the  bar  is  moved,  the  drawing  to 
be  copied  passes  under  the  feeler,  and  the  plate  to  be  engraved  passes,  in  a 
corresponding  manner  under  the  graver.    It  is  obvious  that,  in  this  con- 
dition of  things,  a  continuous  line  would  be  cut  on  the  plate,  and,,  a  late- 
ral motion  being  given  to  the  bed,,  a  series  of  such  lines  would  be  cut 
parallel  to  and  touching  each  other,  the  feeler  of  course  passing  in  a  cor- 
responding manner  over  the  drawing.    If  then,  a  means  could  be  devised 
for  causing  the  graver  to  act  only  when  the  point  of  the  feeler  passed  over 
a  portion  of  the  drawing,  it  is  clear  we  should  get  a  plate  engraved,  line 
for  line,  with  the  object  to  be  copied.    This  is  accomplished  by  placing  the 
graver  under  the  control  of  two  electro-magnets,  the  one  to  draw  the 
graver  down  to  the  plate,  the  other  to  press  it  down  on  it.    The  coil  en- 
veloping one  of  these  magnets  is  in  connection  with  the  feeler,  which  is 
made  of  metal.    The  drawing  is  made  on  a  metallic  or  conducting  surface., 
with  a  rosined  ink,  or  some  other  non-conducting  substance.    An  electric 
current  is  then  established,  so  that  when  the  feeler  rests  on  the  metallic 
surface,  it  passes  through  the  coils  of  the  magnet,  and  causes  it  to  lift  the 
graver  from  the  plate  to  be  engraved.    As  soon  as  the  feeler  reaches  the 
drawing  and  passes  over  the  non-conducting  ink,  the  current  of  electricity 
is  broken,  and  the  magnet  ceases  to  act,  and  by  a  self-acting  mechanical 
arrangement  the  current  is  at  the  same  time  diverted  through  the  coils  of 
the  second  magnet,  which  then  acts  powerfully  and  presses  the  graver 
down.  This  operation  being  repeated  until  the  feeler  has  passed  in  parallel 
lines  over  the  whole  of  the  drawing,  a  plate  is  obtained,  engraved  to  a 
uniform  depth,  with  a  fac  simile  of  the  drawing.    From  this  a  type-metal 
cast  is  taken,  which,  being  a  reverse  in  all  respects  of  the  engraved  plate,, 
is  at  once  fitted  for  use  as  a  block  for  surface  printing.    The  machine  is 
ihe  invention  of  Mr.  William  Hansen,  of  Gotha. — Jour,  of  the  Franklim 
Institute,  from  the  Jour,  of  the  Sac.  of  Arts, 
