Antique of the Month - A Ship’s Stick Barometer (c. 1925)

This month’s Antique of the Month from the Historic Johanna Brotch House is a Ship’s Stick Barometer, circa 1925. It is strictly for maritime purposes and to be used at sea aboard ship. It’s large size makes it very likely it was at some point aboard a steamship, since generally speaking space aboard sailing ships was more limited. It is also British.

Before there were weather satellites and other modern technological developments that allowed ship navigator and captains to know with a degree of certainty about approaching storms, the only real way to predict weather in the future was the use of barometric pressure devices known as barometers.

These worked by atmospheric pressure. As this pressure went up and down (high and low pressure), it was found to trigger mercury to expand or contract in a confined space. Barometers were thus invented to measure this expansion or contraction. A knob on the barometer was turned to move a marker or needle inside the device to align it with the current mercury level. After that position was marked, all that was needed to monitor the barometer over time to see if the mercury rose or fell. An approaching high pressure weather system expanded the mercury while a low pressure system contracted it. The maritime barometer was a relatively simple device and goes back at least a couple of centuries

This barometer is unique in that it comes with custom two-part solid brass gimble system that allowed the stick barometer it housed to rotate freely on the port-starboard-fore-aft axis as the ship bobbed up and down and rolled left and right in the waves. The barometer would always remain vertical with the horizon no matter if the ship wasn’t. The reason for this was that the mercury inside that expanded and contracted with atmospheric pressure needed to remain stable and level with the horizon so it wouldn’t move around and thus jeopardize the accuracy of the readings.

It’s likely this barometer was located inside of the steamship’s navigator’s chartroom or possibly the captain’s sea cabin. It may have been on the bridge, but there were smaller barometer’s available for that space which is the ship’s nerve center with people moving around a lot. A large stick barometer like this would have taken up unnecessary space, thus this one was more likely installed in less busy spaces as the two mentioned.

I hope you enjoy the photos!