Trade card for John Patrick, London, late 18th century.
© Science Museum / Science & Society Picture Library
Trade card showing a 'new improvement of the quicksilver barometer, being made portable by John Patrick in Ship Court in the Old Bailey, London'. Next to some text about the instrument is an illustration showing the rococo design and the inclusion of a looking glass between the marine and pendant barometers. Looking glasses (mirrors) were often placed in the same frame as barometers and thermometers in order to help people to decide what clothes to put on depending on the weather.