ANEROID

a term applied to a barometer in which the pre ure of the air is measured without the use of mercury or other liquid. It consists e entially of a hollow box of elastic metal in which there is rarefied air. Any external pre ure causes a proportionate amount of compre ion of this box, which is conveyed through a woultiplying arrangement to the pointer on the dial. A preliminary graduation in comparison with a good mercury barometer enables the atmospheric pre ure to be shown.