What is "aneroids"

Usage examples of "aneroids".

We had two photographic cameras, an air thermometer, two aneroids with altitude scale to 15,000 feet, and two hypsometers.

In the kitchen were hung our two mercury barometers, four aneroids, barograph, thermograph, and one thermometer.

We were on our feet at once, put together camera, glasses, aneroids, axe, Alpine rope, with some lumps of pemmican to eat on the way, and then went off for a morning walk with the nearer of the two hills as our goal.