A rare baro-thermograph retailed by well-known opticians, Lizars of Glasgow & Edinburgh. There is a silver presentation plaque to the centre of the chart drawer dated 1956. This instrument has two mechanisms & with two pens records both barometric pressure & temperature on the same chart. One pen is slightly longer & deeper than the other enabling the pens to pass each other without touching. Finished in polished mahogany with chart drawer to the base (twin pull knobs) & bevelled glass top it has a neat hole in the glass, with brass rim, to the side to allow air circulation around the bi-metallic thermograph sensor. Fitted with two original ink bottles & holders.