Jules Verne was a writer in France.  During the prime of his writing career (1860's), France was under
                  the reign of Napoleon III.  Some of his most significant internal accomplishments were the rebuilding of Paris, and constructing
                  a railway network.  He helped the French economy shift to large-scale capitalism.  The Industrial Revolution influenced
                  many of his improvements.  This was probably due to the fact that he spent his early years living in England.  France
                  had just entered Vietnam, and, with the help of the British, entered Beijing.  France was in the middle of a war with
                  Mexico at the time this book came out.  (Napoleon III of France)
                   
                  There are many references to the quaternary and tertiary periods during the discoveries inside the Earth.  The tertiary
                  period lasted from 58 million years ago to two million years ago, and the quaternary period lasted from two million years
                  ago to today.  (Geological Timescale)
                   
                  Harry and the Professor mention many philosophers and scientists during their many conversations and debates throughout
                  their journey.  Below is a list and some background information...
                   
                  Edouard Armand Lartet - He was the first to find the fossil ape.  He studied fossils found in French caves. 
                  He also believed that Ice Age mammals and humans had lived with each other. (Ver Steeg, David)
                   
                  Archimedes - A Greek mathematician, he invented many war machines and started the science of pycnometry, which is measuring an
                  object's volume and density.  He is known as the "father of integral calculus." (Rorres, Chris)
                   
                  Jacques Boucher de Perthes - In the 1830's, this archeologist discovered weapons and other tools with fossils of extinct
                  mammals.  The gravel of this discovery indicated that man had lived before what was previously believed, and he came
                  up with the theory of the "Antediluvian Man".  Because They were not consistent with Christian beliefs, his work was
                  not believed until the publishing of Charles Darwin's work. (Boucher de Perthes, Jacques)
                   
                  Horace - He was a famous Roman poet and writer just before the time of Christ.  He was considered the first to be
                  a critic of literary and dramatic works.  He came up with the doctrine of "pleasure and profit".  (HORACE)
                   
                  Sir James Clark Ross - This British Antarctic explorer found the magnetic north pole in 1831.  Ten years later,
                  he claimed all of Antarctica for Queen Victoria.  (Sir James Clark Ross)
                   
                  Sir Humphry Davy - He made many discoveries in the field of chemistry.  His accomplishments include the isolation
                  of potassium, sodium, barium, boron, calcium, strontium, and magnesium.  He improved upon the theory of hydrogen being
                  present in all acids, and discovered that chemical affinity as electric.  (Davy, Sir Humphry)