Manometer

(man-om'e-tur,) or MANO SCOPE. [ From Gr. manos, rare; and metron, a measure; or skopeo, I examine.] (Phys.) An instrument used to show or measure the alterations in the rarity or density of the air. The M. differs from the barometer in this, that the latter only serves to measure the weight of the atmosphere, or of the column of air over it, while the former indicates the density, or rather the elastic force which is considered proportional to the density. [s. 575]