Unpublished paper, 'An attempt to account for the discrepancy between the actual velocity of sound in air or vapour and that resulting from theory' by William Ritchie Ritchie references Isaac Newton's work on the velocity of an undulation in an elastic medium as well as Pierre-Simon Laplace's attempts to reconcile the difference between theory and observation regarding the velocity of sound in air. Ritchie undertakes calculations and experiments regarding the velocity of sound in air or vapour and shares his observations. Annotated in pencil throughout. Subject: Physics / Mechanics Received 30 November 1837. Read 12 January 1837. Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 3 of Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London [later Proceedings of the Royal Society] as 'An attempt to account for the discrepancy between the actual velocity of sound in air or vapour, and that resulting from theory'. November 1836