Unpublished paper and statement, 'An enquiry concerning the source of the light which is manifested in the combustion of inflammable bodies' by Benjamin [Thompson] Count of Rumford Rumford details his experiments on the cause of the light which appears when inflammable bodies are burned, testing various theories on the source of the light and seeking to prove own his theory that light is a vibration or undulation rather than a substance. Followed by a statement by Rumford regarding the originality of his work. Subject: Physics / Thermodynamics This paper was published posthumously in a Rumford anthology edited by Sanborn C Brown: Brown, Sanborn C, editor. Collected Works of Count Rumford. Vol 4, Belknap Press of Harvard UP, 1970, pp 229-250. [1812]