While many searched for a description for the large scale universe, another scale of the universe was being explored by some of the same thinkers interested in the large scale along with others devoted to the small.

The Search for the elementary constituents of matter
         Early greek philosophers and other philosophers of the world have entertained the thought that there are fundamental constituents of matter and reality.
         Earliest documentation of this idea leads back to 4th century B.C.  by a Chinese
                    philosopher Hui Shih
       
        Democritus is generaly credited with the hypothesis that all the elements are made up of atoms.
       
        Galileo and Newton give us ways to study the motions of particles that have an inertial property                        called mass .
 
         Daniel Bernoulli - begins study of gases in terms of mechanical motions of particles
                  Begins the Kinetic theory of gases  (1738)

          James Dalton -introduced the hypothesis that atoms are the smallest unit in elements that can                          take part in chemical procceses  (1803)

           Amedeo Avogadro - relates pressure to particles hitting the sides of a container
                    Avogadro's Law (1811) helps in the formulation of the size and weights of molecules and                       elements

           Ivanovich Mendeleev (1834-1907) -disovers that when elements are arranged acording to                               weight thier properties exibit periodic behavior
 
            Max Planck (1858-1947) - explains  the spectrum of black body radiation in terms of                                     electromagnetic energy absorbed and emitted by atoms in discrete packets - quanta (1900)
                     gives us planck's constant h

             Einstien proposes that the quanta exchanged are photons

This is essentually the point in which our two histories converge on Einstien.  Now  the timeline will be based on discovery rather than person.

1897 - The Electron is discovered by J.J. Thomson , Crookes and others while studying cathode rays

1905 - Photon as Quantum of radiation - Einstien extends Planck's idea assuming light as the quanta of             radiation called Photon's. Also shows that Energy of a quantum is given by E= hf where                         f =frequency of photon. This is proved through the photoelectric effect.

1911- Rutherford Model of atom

1913- Bohr produces his theory for the hydrogen atom. Describes quantized energy levels of hydrogen.
            This is the starting point of the formation of Quantum Mechanics in the late 1920's