my intepretation of the H-effect is that it is analogous to the triple point of solid, liquid and gas of a substance. see the site at
http://www.sv.vt.edu/classes/MSE2094...s/triplpt.html
But for the 4 fundamental forces, the H-effect is the quadruple point where the forces are not distinquishable from each other. This is a state of grand unified forces not just the fundamental forces but also include atomic force, molecule forces (intra-molecular and inter-molecular), static forces, frictional forces, Hook's forces or spring forces, elastic forces, surface tensions, etc.
As for Tesla's legacy, it is his idea of generating electrical power out of the vacuum that made him far ahead of his time (he died a penniless man still believing that his idea should have worked out). But since the discovery of the electroweak force, his idea might be feasible now.