1592-1655 1844-1906 194 19thcentury ancient atomism atoms austria biography boltzmann brownianmovements chemicals chemistry constitution cosmology education gassendi historiography history lucretiuscarus ludwig matter medieval nuclearphysics philosophy physicists physics pierre properties qc173 quantumtheory radiochemistry religionandscience science statisticalphysics studyandteaching thermodynamics titus valence(theoreticalchemistry)