The  application  of  a  mere  mechanical  device,  requiring  no  inven-
tion, to  a  machine  which  was  conceived  by  another  and  is  being
actually  reduced  to  practice.  Marshall  v.  Mee,  1  MacArthur  Pat.
Cas.  229.
The  mere  repetition  of  a  well  known  process  by  which  a  metallic
paint,  heretofore  known,  may  be  obtained  fi"om  waste  matter.  Pe
Maule,  1  MacArthur  Pat.  Gas.  211.
The  use,  in  illuminated  vault  covers,  of  polygonal  glasses  of  an
inverted  pyramidal  form  instead  of  lens-shaped  glasses  previously
used,  there  being  no  evidence  of  the  actual  results  in  practice.  Pe
Jackson,  1  MacArthur  Pat.  Cas.  485.
An  improvement  which  consists  merely  in  the  employment  of
an  obvious  substitute,  but  does  not  involve,  to  any  considerable
extent,  the  exercise  of  ingenuity.  Pe  Everson,  1  MaoArthur  Pat.
Cas.  406  ;  May  v.  Fond  du  Lac  County,  27  Fed.  Bep'r,  091.
Otherwise,  if  the  substitute  is  not  obvious,  and  is  new  and  use-
ful.    Ladd  V.  Tucker  Manuf.  Co.,  4  Pann.  <&  A.  Pat.  Gas.  344:.
A  mere  change  in  the  details  of  mechanical  construction  of  a
device,  as  in  the  relative  position  and  mode  of  attachment  of  its
par.ts,  .but  producing  no  new  effect  {Pe  Bishop,  1  MaoArthur  Pat.
Gas.  518  ;  Dane  v.  Illinois  Manuf.  Co.,  6  Fish.  Pat.  Cas.  124  ;  3
Piss.  314;  Hancock  Inspirator  Co.  v.  Lally,  27  Md.  PepW,  88)  ;
though  a  change  in  arrangement  of  old  parts  of  a  combination


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which  effects  efficient  co-operation  may  involve  invention.     Troj
Laundry  Machinery  Co.  v.  Bunnell,  27  JFed.  Rep'r,  810.
