Unpublished paper, 'Comparative observations made with a mountain barometer and the compensating barometer' by Samuel B Howlett Howlett describes his compensating barometer. Includes a table of comparative observations taken with a mountain barometer and the compensating barometer, which shows the date, mountain barometer (apparent, temperature, reduced), Mr Howlett's barometer, and difference between the measurements of the two barometers. Annotations in pencil throughout. Includes a drawing of Howlett's compensating barometer. Subject: Meteorology / Engineering Written by Howlett at 83 1/2 Pall Mall [London]. Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 4 of Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London [later Proceedings of the Royal Society] as 'Description of a compensating barometer, adapted to meteorological purposes, and requiring no corrections either for zero, or for temperature'. 7 March 1839