Walnut Cased Barograph, 1890s

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John Trotter walnut-cased Barograph, having five beveled glazed removable lid, and a drawer below to house the charts. The mechanical … Read more John Trotter walnut-cased Barograph, having five beveled glazed removable lid, and a drawer below to house the charts. The mechanical eight-day movement is housed in the drum, fitted with a seven-day chart that covers one full rotation of the drum. The ink trace, or barogram, on the recording paper, is a visual record of changes in pressure. The aneroid barometer mechanism has seven stacked vacuum capsules and utilizes a gate suspension, a refinement developed to improve sensitivity. The barograph has a thermometer and its original glass ink bottle recessed into the case. Dimensions Height 9 Inches Width 14.5 Inches Depth 9 Inches See less