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 can be held up and also the comparative grayness of the smoke judged. Prices of smoking cigarettes keep https://broadfar.com/oraco-pioneering-a-smokeless-future-with-innovative-nicotine-delivery/