Coronavirus (COVID-19) While museums are closed, the Science and Society Picture Library prints site is fully operational and we have added an FAQ page here.

Pixii pyrometer, mid 19th century.

Pixii pyrometer, mid 19th century.
3 4 c m
actual image size: 32cm x 26cm


A solid expands when it is heated, because its molecules vibrate more vigorously and need more space. This pyrometer, or 'heat-measurer', demonstrated how a metal rod increased in length as it was heated by a gas flame placed beneath it, and shrank again as it cooled.

Image Details

Image Ref.

© Science Museum / Science & Society Picture Library

buy a print

Select size
Select finish
How many prints?

buy a framed print

buy a canvas

buy a framed canvas