ellers ▁& ▁Co ., ▁which ▁continued ▁to ▁operate ▁until ▁ 1 9 4 7 ▁when ▁it ▁was ▁sold ▁to ▁the ▁Cons olid ated ▁Machine ▁Tool ▁Corporation ▁and ▁re located ▁to ▁Ro chester , ▁New ▁York . ▁ ▁In ▁ 1 8 4 7 ▁S ellers ▁was ▁elected ▁a ▁member ▁of ▁the ▁Franklin ▁Institute , ▁where ▁he ▁served ▁as ▁a ▁member ▁of ▁the ▁Board ▁of ▁Man agers ▁from ▁ 1 8 5 7 ▁to ▁ 1 8 6 1 ▁and ▁again ▁from ▁ 1 8 6 4 ▁to ▁ 1 8 9 2 , ▁and ▁as ▁president ▁from ▁ 1 8 6 4 ▁to ▁ 1 8 6 7 . ▁At ▁a ▁meeting ▁on ▁September ▁ 1 5 , ▁ 1 8 6 4 , ▁he ▁presented ▁a ▁uniform ▁system ▁of ▁sc rew ▁threads ▁which ▁with ▁its ▁angle ▁and ▁its ▁flat ▁top ▁and ▁bottom ▁differ ed ▁from ▁Whit worth ' s ▁British ▁standard . ▁Within ▁a ▁few ▁years , ▁the ▁system ▁had ▁been ▁adopted ▁by ▁the ▁government ▁work sh ops , ▁leading ▁rail road ▁companies , ▁prominent ▁machine ▁tool ▁build ers ▁and ▁others , ▁under ▁the ▁various ▁names ▁of ▁the ▁United ▁States , ▁S ellers , ▁or ▁Franklin ▁Institute ▁Systems . ▁ ▁Pos itions ▁American ▁Philosoph ical ▁Society ▁- ▁elected ▁member ▁( 1 8 6 4 ) ▁Franklin ▁Institute ▁- ▁elected ▁president ▁( 1 8 6 4 ) ▁University ▁of ▁Pennsylvania ▁- ▁elected ▁trust ee ▁( 1 8 6 6 ) ▁Fair mount ▁Park ▁- ▁appointed ▁member ▁of ▁the ▁first ▁commission ▁( 1 8