Julien Fiez, founder of Belfort Instrument Company is credited with early U.S. development of the aneroid barograph for the company he founded in Baltimore in 1876.
These early devices functioned much the same as bellows type barometers function today by measuring the expansion and contraction of a metal bellows device that has a partial vacuum on the inside and is exposed to atmospheric air pressure on the outside. The bellows contracts with high atmospheric air pressure and expands with low atmospheric air pressure and is mechanically connected to a recording pen or needle indicator.
Belfort Instrument Company still manufactures aneroid barometers that meet stringent U.S. Military Specifications (Mil-B-17089) and National Weather Service Specifications.
*(Aneroid: operating by the effect of outside air pressure on a diaphragm forming one wall of an evacuated container)