polygraph

John A. Larson

Jan 11, 1892

carbon.ucdenver.edu/~mryder/polygraph_este.htmljohn A larson was born in shelburne, canada

Leonarde Keeler Birth

May 30, 1903

http://www.lie2me.net/thepolygraphmuseum/id12.html
leonarde keeler was born in california, 1903

polygraph

Feb 1, 1921

historyofscience2011v2.blogspot.com/2011/04/john.htthe
polygraph was invented by john augustus larson

designed

Apr 30, 1921

http://www.pbs.org/wnet/innovation/episode8_essay1.htmlJohn Larson and Leonard Keeler designed the portable polygraph in 1921

Emotograph

Jun 30, 1924

http://www.lie2me.net/thepolygraphmuseum/id12.htmlLeonarde Keeler’s first handmade polygraph instrument, he called the Emotograph

Leonard&Larson devloped Polygraph

Mar 2, 1925

inventors.about.com/od/fstartinventions/a/forensic_2.html
leanord and larson created a polygraph that used inked pens for recording the changes in a subject's blood pressure, pulse rate and respiratory patterns,

leonarde keeler

Aug 30, 1949

leonarde keeler died on 1949