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What chemical expirements did James Watt study?
James Watt passed the chlorine into a weak solution of alkali, and obtained a turbid solution that appeared to have good bleaching properties

Question: was there a significant discovery when Berthollet reacted Hydrocloric acid with manganese dioxide?
Self-contained rewrite: was there a significant discovery when James Watt witnessed Berthollet's experiment reacted Hydrocloric acid with manganese dioxide?