Ringelmann scale. A evaluate of smoke color. Invented by Professor Maximilian Ringelmann in Paris in 1888, it is actually a card with squares of black, white and shades of gray that is held up along with the comparative grayness of your smoke judged. Charges of cigarette smoking carry on https://broadfar.com/oraco-pioneering-a-smokeless-future-with-innovative-nicotine-delivery/