What is a Banjo Aneroid Barometer?

After the advent of the Vidi style aneroid in 1844 brass ones were made almost exclusively but by around 1860 manufacturers saw the benefit in utilising an aneroid movement instead of the mercury tube in a banjo case.  These early ones were often of the same shape as the Victorian mercury wheel barometers then being made but often slightly shorter as there was no need to have such a space for the tube.  As time progressed we find by about 1875 it is more common to see oak cased banjo shaped barometers with a thermometer above the dial, again usually with ceramic but sometimes nicely engraved brass dials or finely printed card dials, later by 1900's white glass was introduced and became quite popular during the Edwardian period.  These banjo shaped barometers come in many shapes and sizes and sometimes finely inlaid models turn up.  They are often more easily identified by having carved cases whereas most mercury wheel barometers, which can look similar to the novice, are often plainer.