Xerography--Where It All Began

"The slide was then removed and lycopodium powder was sprinkled on the sulfur surface. By gently blowing on the surface, all the loose powder was removed and there was left on the surface a near-perfect duplicate, in powder, of the notation.

"Both of us repeated the experiment several times to convince ourselves that it was true, then we made some permanent copies by transferring the powder images to wax paper and heating the sheets to melt the wax. Then we went out to lunch and to celebrate."