ATCO Compensated Aneroid Pocket Barometer & Altimeter with Case & Satchel. This antique ATCO Gilt Cased Pocket Barometer Altimeter is in it’s original leather case, it was often used for Hot Air Ballooning, Mountain Climbing, or walking. Circa 1890s – 1900s. This is an aneroid barometer, a device used for measuring atmospheric [...]