Systematics high-temperature heat content

J. J. Berzelius began a systematic study in his laboratory in Stockholm. He mixed quartz, iron, carbon and charcoal, and heated the mixture up to a very high temperature. A compound between iron and silicon, an iron sflidde, was formed. This he treated with hydrochloric acid and measured the amount of hydrogen evolved. He observed that more gas was formed than what corresponded to the iron content of the sample. The metal of the quartz had been present in the beaker ... 

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