Quarto. Two copies of the work bound together. 133-136; 133-136pp. Contemporary plain tan paper wraps. Title in manuscript to upper wrap, light soiling and wear, ink-stamps of the Royal Meteorological Society to upper wrap and head of drop-title.

An excerpt from a journal of philosophical transactions describing the construction of an improved differential barometer which may be applied to the measurement of the force with which heated air ascends. The invention in question applies water rather than mercury as a part of the mechanism thereby providing a more perceptible change in level, thus allowing for more accurate recordings to be taken.