"The protracted eudiometrical enquiry... taught Cavendish... the maximum amount of diminution... one-fifth of the original volume of the air... was the dephlogisticated part, or pure air (oxygen), of the atmosphere, which disappeared during combustion, so that he was now fully prepared to enquire what had become of the lost oxygen. His account... forms the first series of his Experiments on Air... read to the Royal Society in January 1784... a year after the paper on the New Eudiometer..."