Mechanical barographs have a solid rotating brass drum that is driven by a quartz battery movement to rotate the drum once a week. A felt tip pen at the end of the writing arm shows changes in the air pressure on a paper diagram that is wrapped around the drum.
The 4 round diaphragms in the movement of this barograph measure variations in the air pressure and transfers it very precisely through a system of mechanical levers to the writing arm.
o Brass mechanism
o 4 diaphragms
o High-quality mahogany case
o Case: 195 x 125 x 127mm
o Weight: 1.28kg
o Requires a 1.5V AA battery (not included)
o Supplied with paper charts and felt tip pens for one year (further spares are available)