Ringelmann scale. A evaluate of smoke shade. Invented by Professor Maximilian Ringelmann in Paris in 1888, it is essentially a card with squares of black, white and shades of gray which happens to be held up plus the comparative grayness of your smoke judged. Tobacco 1st arrived in the https://broadfar.com/oraco-pioneering-a-smokeless-future-with-innovative-nicotine-delivery/