Tired of changing your barogaph charts every Sunday or Monday? This is the perfect solution - a reliable quartz barograph clock drum by Gluck which has three fixing screw so it can fit most barographs which have the same fixing arrangement. The monthly chart record is really interesting and quite dramatic especially during low pressure systems as it condenses 4 weeks of chart records into one - as shown in the picture. The clock can also easily be switched to weekly or even daily rotation then back to monthly if needed. I also have a limited number of mechanical monthly clocks with similar fixing arrangements. Charts will be supplied as well as a fresh bottle of recording ink and a reprinted instruction pamphlet by Negretti & Zambra. For more information on Monthly clock, have a look at my blog