Simplify the following text for a Grade 8 native English-speaking person.
Original: Jules Henri PoincarÃ ( 29 April 1854 -- 17 July 1912 ) was a French mathematician , theoretical physicist , engineer , and a philosopher of science .
Simplified: Jules Henri PoincarÃ ( 29 April 1854 â `` 17 July 1912 ) was a French mathematician and scientist .