Earliest illustration of the Leyden jar, 1744. The charge was generated by revolving the glass globes at the left, and was transmitted to the central conductor supported by silk cords. A wire led down thru the mouth of the glass bottle partly filled with water. When the experiment held the bottle in one hand and advanced his other hand to the wire, his arms and chest formed part of the equalizing circuit and he received a very strong shock. Johann Heinrich Winckler (Winkler) (March 12, 1703 - May 18, 1770) was a German physicist. In 1744 he published "Thoughts on the properties, effects and causes of electricity". He also investigated the electrical attraction and electrical luminous phenomena. He was elected to the Royal Society in 1747. The Royal Society, which spelled his name Winkler, published information about his electrical experiments in their Philosophical Transactions (first journal in the world exclusively devoted to science). This image has been color enhanced.