what were his contributions?
He did much to improve and systematise the processes of analytical chemistry and mineralogy.
Martin Heinrich Klaproth
An exact and conscientious worker, Klaproth did much to improve and systematise the processes of analytical chemistry and mineralogy. 
where did the us get uranium for the atomic bomb Congo. what is this project about? It was a research and development undertaking during World War II that produced the first nuclear weapons. what is the date of this undertaking? From 1942 to 1946. where is it based? UNANSWERABLE who manages or backs this project? It was led by the United States with the support of the United Kingdom and Canada. do you know about any particular nuclear product that it might have eveloped? In parallel with the work on uranium was an effort to produce plutonium. who discovered the former nuclear item? Martin Heinrich Klaproth. was it used before that? Yes, Henri Becquerel discovered radioactivity by using uranium. who was this person you just mentioned? He was a French engineer, physicist, Nobel laureate, and the first person to discover evidence of radioactivity. any notable experiments that he may have carried out? He made the discovery that radioactivity could be used for medicine. was he honored for that? No, but he was honored for his discovery of the radioactivity of uranium. was this nuclear item that you mentioned in the last has any connection with cold war? No. what are its resources? UNANSWERABLE where is it naturally found? Canada, Australia, Kazakhstan, Russia, Namibia, Niger, Uzbekistan, the United States, Argentina, Ukraine and China. what kind of effects does it have? Normal functioning of the kidney, brain, liver, heart, and other systems can be affected by uranium exposure. the person who discovered this item, who was he actually? He was a German chemist.
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Martin Heinrich Klaproth [SEP] Contributions
An exact and conscientious worker, Klaproth did much to improve and systematise the processes of analytical chemistry and mineralogy. His appreciation of the value of quantitative methods led him to become one of the earliest adherents of the Lavoisierian doctrines outside France. Klaproth was the first to discover uranium, identifying it first in torbernite but doing the majority of his research on it with the mineral pitchblende. On 24 September 1789 he announced his discovery to the Royal Prussian Academy of sciences in Berlin. He also discovered zirconium in 1789, separating it in the form of its ‘earth' zirconia, oxide ZrO2.