Thomas Edison tried two thousand different materials in search of a filament for the light bulb. when none worked satisfactorily,his assistant complained," all our work is in vain.
we have learned nothing."
Edison replied very confidently,"oh,we have come a long way and we have learned a lot.we know that there are two thousand elements which we cannot use to make a good bulb."
we have learned nothing."
Edison replied very confidently,"oh,we have come a long way and we have learned a lot.we know that there are two thousand elements which we cannot use to make a good bulb."
