This paper proposes inherent derivations theoretically from the one-dimensional equations of Maxwell on the basis of exact partial differential equations in free orthogonal space. Apart from the Lorentz transformations with no absolute perfection to become infinity at a point that any particle with mass to be unattainable to the speed of light and the quantum mechanics with unequivocal explanation for wave-particle duality. With those background, the first theme derived through a classical process, is the so-called wave-particle duality. New duality in this paper means that electromagnetic energy density r(E), momentum r(p) and mass density r(m) in mechanical corpuscular system can be, respectively, described as one-dimensional wave equation form, traveled at the speed of light equal to reciprocal square root of electromagnetic constant, q(0)u(0) product of invariant permittivity q(0) and permeability u(0) in free orthogonal space with homogeneity, isotropy, linearity and differentiable continuity with respect to independent variable space and time on the basis of exact differential equations. The second derived is that the mass density r(m) [unit, kg/Cub(m)], the momentum density r(p) [kgm/s/ Cub(m)], the energy density r(E) [J/Cub(m)], electric flux density D(x) [As/Sq(m)] and magnetic density B(y) [Vs/Sq(m)] is, respectively, able to be expressed as the so-called wave equation function as ∂(∂(g(z, t)/∂z)/∂z = q(0)u(0) ∂(∂(g(z, t)/∂t)/∂t, through each density replaced g(z, t) function into them. So, all of them can travel concurrently at the speed of light in the space: r(m), r(p), r(E) in wave form on root mean square unit are able to be described, respectively, A(m)Exp(4πja)/2, A(p)Exp(4πja)/2, and A(E)Exp(4πja)/2, A(D)Exp(2πja)/Sqrt(2) and A(B)Exp(2πja)/Sqrt(2), where A(m), A(p), A(E), A(D) and A(B) are, respectively, amplitude in wave form. The third derived is that the mass density r(m) equals to the product of the energy density r(E) and q(0)u(0): r(m) = q0)u(0) r(E), using new concept specified as mass beam b(m) [unit: kg], momentum beam and energy beam element assumed from property of the well-known light beam, the mass beam element equals the energy beam element b(E) [J] times q(0)u(0): b(m) = q(0)u(0) b(E), being equivalent to Einstein equation of particle rest mass equivalent to the energy divided by the speed of light. The Forth derived is that an indeterminacy term product of the momentum and indeterminable space interval in mechanical corpuscular system is equivalent to determinable electromagnetic flux in electromagnetic system, so the term is equivalent to the uncertainty principle. From the above-mentioned thought, the Fifth will be able to be postulated that there is an absolute rest free spacetime with orthogonal relationship between a common time and the other spaces with homogeneity, isotropy, linearity and differentiable continuity with respect to independent variable the space and the time on the basis of exact differential equations for the space permits light to travel at invariant speed of light.